Bad Moon Risin’

• Posted By : Neal Collier
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If you are a newcomer to the Florida Panhandle, Coastal Alabama or Mississippi, you are learning what we mean by “the wet side” of a hurricane. If you you are in Louisiana, you have my sympathies. For us natives, it’s the price of living in paradise.

The wet side is the right or eastern side. Everything spins around the eye, counterclockwise, bringing in moisture off the Gulf and dumping it on the land. By the time the swirls make it around to the left side, they’ve pretty much dumped it all, so that makes the left side the dry side. How wet is it? You can’t get out my south driveway and the north driveway may soon rival the Grand Canyon as an attraction. This morning I had to go to the mailbox in an EV equipped with Mud Crusher tires.

The last tropical storm that came through to the east gave us beautiful weather. Not so, today, 250 miles from Ida’s landfall. We still have leaning trees from last year’s Hurricane Sally. It wasn’t a big one, but it nailed us, dead center, and I’m still waiting for roofers to return my call.

Fortunately, we are not getting the winds, like Mississippi is. Wet ground and winds mean the trees fall over on the power line and the lights go out. That is, they go out if you don’t have solar, battery or generator backup. And since it is a dreary, wet day, it is a good time to talk about cloudy weather solar performance.

How’s that solar working out today? In short, it sucks. If you are off grid or have a hybrid system, learn that and learn to deal with it if you know you are in for a rainy spell or worse. I switched the main circuits over to the grid to conserve battery without waking the generator. I did not go into total conservation mode, foregoing my air conditioned X-Files marathon on the big screen in the man cave. The Cave stays on solar. The house a/c is also hardwired to the solar, so battery is still providing quite a bit of power.

I’ve been watching 2 banks of panels very closely, comparing them because one is pointing south and one is pointing west. I am planning on reporting the performance comparison, but the data is useful for today’s purposes. The south bank is rated for 2700 watts and the west bank is rated for 2500 watts, so they’re pretty close. The first thing you learn is that there are degrees of “cloudy”. There’s ominous, gray cloudy. I check the meters a while ago in that state and one charge control reported that it was resting. Lazy thing. Another reported 50 watts. 50 out of 2700! There’s also medium and bright overcast. They do better, maybe cranking out 20% of rated power. So now you know why they call them solar panels. If you want the real power you have to have the sun shining.

Ok, you know it is coming, a storm or a period of overcast. If you live off grid you can’t just throw the switch. You either have to cut back or fire up the generator. In the old days of solar, when panels were astonishingly expensive, generators were run a lot. Turning $3 worth of diesel into 50 cents worth of electricity is not economical, but sometimes it needs to be done. In my system, I like to run the generator once a month for up to an hour. The system specifies running it more to equalize the lead acid batteries every 90 days and really long and hard to desulphate every 6 months. I’m considering my monthly hour, today, to exercise the generator and boost the batteries a bit.

Then there’s conservation. Cut back or eliminate a/c, if you have it. Cloudy weather naturally cuts back the need and mine has been running very little, today, with outside temp at 77F. A fan in the rooms that are occupied is great, but don’t leave the lights or fans on when you leave. If the kitchen is all electric, quick cooking in the microwave can save a lot of battery power. A Mr. Coffee or Keurig coffee maker is pretty efficient for heating water for oatmeal or noodle cups (but don’t leave the Mr. Coffee on). I grouse about the dishwasher. My wife likes to run it early in the morning when the batteries are low and before the panels get fired up and she runs it more often than I think is necessary. That uses about a kilowatt, but I try not to harp on it too much, lest I find myself doing the dishes.

I went out between showers and came in around 130pm from checking the meters and tending a few chores, to find the clothes dryer was running. That’s on the grid, mostly, but the Zero Export Grid Tie system helps out a bit…when the sun is shining or the batteries are fattened up. I had just observed that the dryer was consuming 5kw while the 2kw of solar panels were contributing 36 watts. At considerable peril to my well being, I brought this to the attention of my wife. “I know, I know. Don’t use the dryer in the morning (before the sun comes up), in the afternoon (when it draws in heat), in the middle of the day (actually that’s ok), on rainy days (no sun) or at night (no sun), right?” says she. “Yep, that’s pretty much it,” I said with a smile. I did not pursue the matter further. The electricity for the dryer cost me 65 cents and I was not injured, so I guess that’s a pretty good deal.

If there are any bullet points for this rambling dissertation….
-Anticipate expected times of low solar output.
-Cut back power consumption where you can.
-Get everybody in the house in conservation mode (be diplomatic).
-Do your scheduled maintenance generator runs during cloudy weather.

–Neal

Rack ‘Em Up!

• Posted By : Neal Collier
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They’ve gotta go somewhere!

A while back I mentioned that I had a glut of solar modules. That does not mean I have too many, they just are not all up and running. I am in the process of getting another 10 panels up, this time on a ground mount facing a bearing of 260 degrees. That’s almost west! That’s not where most people point them, but I like to mix it up a bit and late afternoon is my peak summer use time.

If you have made up your mind that you are “goin’ solar” you need to consider where you are going to put them. On the roof is a pretty good option if you have a new roof and a small yard. If your roof is 20 years old, you should consider refreshing that before putting up solar panels, because it is a lot of work to take them down and put them back up again when you do get your roof replaced.

Floating solar has become “a thing” amongst the big players. We are going to have to put up many acres of modules to cover all of our power needs, present and future, but we still need acres upon which we can grow food and build houses. Floating is only a good option if you have a lake in the yard.

Rural folks, like me, and those with a good lot and no zoning restrictions can put them out in the back yard on ground mounts. There is a lot of leeway in designing a ground mount. Don’t be happy with a frame that will just hold up the panels on a calm day. Consider the worst case in weather events. We have hurricanes, at my house, so I plan for dealing with a good strong breeze several times a year.

There are no hard and fast rules. There is an outfit in France that has put up a farm, mounting the panels on random oak branches placed in the ground. They want to prove how “sustainable” and “green” they are, I guess. Florida termites would probably appreciate that approach. Within a year the panels would all be on the ground.

Speaking of which, one solar farm outfit is building on the premise that panels are so cheap, they’ll just buy more of them with the money they save on ground mounts and trackers. Yup, they are just laying the panels out in neat rows on the ground. Not sure how that is going to play with weeds, dirt and bird splat, but they seem to think it is a good idea. The 10 panels I am mounting have been in similar arrangement, except they’ve been on or leaning against a trailer for a while. This would be a very vulnerable situation in an area that has hail. We don’t.

I have made ground mounts with 4×4 posts and 2×4 diagonals, using treated wood in consideration of the aforementioned termites. I’ve also made them with 4x4s and metal sign posts. Unlike a former neighbor who made his corral from posts stolen from a local park, I got mine from the county’s stock of material to be discarded.

A friend is using mounts made of square tube steel. They were originally mounted on mobile solar generator trailers, so he will have to heavily ballast them or tie them into some ground anchors of some sort.

So, for ground mounts, I will start with a couple of points. First off, people will not necessarily be impressed if your mounts place your panels in perfect, straight rows. They WILL notice if they are are wobbly and erratic in their mounts. The best tool for making a neat ground mount is a piece of string! I rooted in my archæology kit and found some fluorescent string with a mounting block and a string level. If you don’t have an archæology kit, then Home Depot or the hardware store will have these items.

Secondly, observers will not be impressed if they find your modules in their yard after a storm. Some installations I have seen in the islands and on rooftops use ballast or heavy stuff to hold racks down. I find there is no substitute for concrete in the ground. I dig as deep as I can with posthole diggers and make the hole wider at the bottom than at the top, so it’ll take more effort to uproot the posts. Also, put some concrete in the hole first, so steel will not be in contact with soil. Steel holds up very well in contact with concrete.

Back around 1970, we had an oil boom around here and Dad had some pieces of used drill stem for an RV shed. Dad and the shed are gone, but I saved the steel. It is good, heavy stuff and it was free, so that’s what I used. I like to avoid spending money when I can, but it catches up with me anyway. I still needed cutting discs, welding rods, clamps, nuts, bolts and washers. And concrete. The drill stem is providing the primary mount and I had exactly enough for 10 panels.
My original plan was to fabricate some U-bolts from threaded rod stock, but then I discovered that 2 1/2″ rigid conduit clamps were a perfect fit. And easier. If I make my secondary (lower) mounts adjustable then the seasonal angle can be adjusted, should I desire to do so. I am leaning toward a fixed mount.

I’ll let you know how it all turns out when I am done, but I just wanted to throw out some ideas for you. Also, I wanted to remind you that something as simple as a piece of string can be an important tool in positioning or laying out your array.– Neal

PS– Read the specs of panels you plan to order or, better, measure the panels you have. One fellow I know got some nice steel racks designed to hold 30 modules. STANDARD 1 meter wide modules. He was so thrilled to find a deal on some odd high-watt modules that he failed to notice that the more powerful panels were a bit too wide and it ended they would not all fit.

This Is NOT a Generator Plug

• Posted By : Neal Collier
• Technical Blog
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It is getting to be that time of year, when a lot of people think about getting a generator in case there is a hurricane.

Even if you have solar, it is a good idea to have a generator for times of extra load or for equalizing batteries. There’s also no guarantee all your modules will still be where they were before the storm, once it all settles down.

The thing about generators, though, is that so few people do it right. You need a proper generator plug and a transfer switch. The transfer switch lets you select the power company or the grid as your power source. It also prevents your generator from backfeeding into the neighborhood, possibly killing a lineman, but most certainly killing the generator. If you have solar, your inverter may also have a transfer switch built in to allow the generator to take over. That’s all well and good, but where people run into trouble is how they connect the generator to the house.

A lot of people take what is essentially a double-ended extension cord and plug into a wall outlet for a small generator or a 220 socket normally used for the clothes dryer. What’s wrong with that? First of all, if the plug is not securely plugged in, it’ll soon be on the floor where someone might touch those energized prongs. Second, if the meter is not pulled or the breakers pulled, power can go out into the world. A proper generator plug uses a “Hubbel” or twist-lock connector that won’t fall out and the generator side of it has no exposed contacts.

Many years ago we had a storm that was unexpectedly fierce and the power was out for weeks. I did not have any provision for a generator, but I had a big old diesel rig out in the barn, so I improvised. I brought the power in, hardwired to one of the outside a/c disconnect boxes. The main breakers were pulled and I removed the power meter, replacing it with a protective sheet.

Was the power company upset that I broke the seals and snatched out the meter? No! They thanked me for not killing them.–Neal

A Different Angle

• Posted By : Neal Collier
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Traditionally, we’ve been told to point our solar arrays to the south.  There were guidelines on the angle from horizontal, too.  Pretty much all of this is open for question, now.

You may have noted my recent posts on the arc the sun travels and my experiments with a vertical array.  There’s more to it.  Instead of my next expansion of the Solar Shed being linear along the airstrip, I’ve decided to make a portion of it extend to the north, with a north-facing slope for the solar roofing tiles.  I had thought to add just a carport for the EVs on the backside, but the Man Cave needs room for a fitness center and other activities.  Careful observation has shown that a north slope could pick up quite a bit of morning and afternoon sun.

It’s not just me, thinking this way, and people who don’t have a roof with a perfect southern exposure needn’t fret when wanting to add solar.  Recent studies in Australia have found that splitting the array between northeast and northwest is a good plan.  Bear in mind that the Land Down Under is upside down, or we who dwell in the Northern Hemisphere would say southeast and southwest.

Why?

Well, think about when you use your electricity and the possibility that maybe sometimes you are making too much and other times not enough.  In grid tie situations, there are sometimes limits on how much the power company allows you to export.  Also, places that have high concentrations of solar, have run into problems when everybody is making max power at the same time.

Typically, we use the most power in the morning and evening.  Think about it.  You roll out of bed and go turn on Mr. Coffee.  You stumble into the shower, which activates the water heater.  You pop a couple of frozen waffles into the toaster or nuke a frozen omelette.  You might even fry up some bacon and eggs on the stove.  After breakfast, you toss the dishes into the dishmasher (yeah, that’s what we call it) and off you go to work.  Lots of electricity was consumed.

Maybe you set back the thermostat during the day, so it cycles a little and so does the fridge.  Not much goes on during the day.

You come back home, after work, and hit the thermostat.  Turn on the tube for the evening news.  Run pretty much everything in the kitchen to get supper ready.  Maybe do a load of laundry.  More water heater and more dishwasher.

Lots of power in the morning and evening.  If your arrays (instead of array) pick up more power early and late, it can be self consumed and not run as much back into the grid.  This minimizes the chance of exceeding a limit.  It is very beneficial in areas where they pay you, say, 4 cents for your power and charge you 12 cents to get it back.

There are benefits off grid, as well.  I see in my own array that my batteries sometimes are just begging for some morning sun, especially these mornings where the A/C needs to really get buzzing early.  Here, we define a warm day as 80 by 8 and a hot day is 90 by 9am.

Then, late in the afternoon, that afternoon sun is way off the axis of the south array, but really cooking the back side of the house, placing maximum load on the A/C.  Not only that, I get hungry about then and all the kitchen stuff comes online.

At solar high noon, my batteries are pretty much topped and more power is being generated than is being consumed.  That means I am just throwing power away.  Part of that will be alleviated with my next battery upgrade and that will allow me to put more load on the system.

Another angle on this, so to speak, is time of year output.  Come winter, the sun will lean a bit more to the south.  The array on the north slope may get little or even no direct exposure to the sun.  They will put out a bit because of incidental insolation, but the lower angle on the southern array will produce more power due to closer alignment to the sun.  Then there is the matter of load.  I rarely run the A/C in winter.  I suppose I could run the heat pump.  That would save on the efforts involved with firewood.  Firewood is good exercise, badly needed exercise, but there may come a time when I can’t handle that anymore.  The problem with heat pumps, which gas companies are quick to highlight, is that they don’t pump much heat when it is truly cold.  That’s why we have a wood furnace boiler out in the backyard.

For now, though, summer is our high power consumption time. Right now, probably about 90% of my solar output is going to air conditioning and that is more than the rest of the loads combined.

Therefore, I propose that you carefully study what your loads are, and when, and you might find your options for an effective solar array are better than you thought.–Neal

AMPACITY

• Posted By : Neal Collier
• Technical Blog
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AMPACITY. That’s our word for the day. If you think it sounds like a mashup of “ampere” and “capacity”, then give yourself a gold star. That’s exactly what it is.

So, what’s it all about? If you are moving electricity around with wires, then you need to understand that you need to choose the wire of the right ampacity. Really thin wire could melt and start a fire. Too thin wire would work safely, but you might lose some precious watts to resistance. Wire that is too fat is fine, but expensive. Choose the right wire and you will end up with a system that is safe and cost effective.

Lower voltages require thicker wire of a higher ampacity than higher voltage. In my house, most of the outlets are on 20 amp circuits delivered by 12 gauge wire. This might sometimes be listed as 12 AWG. Some houses are wired with 15 amp circuits and 14 gauge wire.

Battery cables tend to be thicker on 12 volt systems than on 24v or 48v systems. Why? To get the same number of watts (Watts = Amps X Volts) it takes 4X the amps on a 12v system than on a 48v system.

On a household 120vac system, it is ok to lose 2 volts in the resistance of the wire, but losing 2 volts between the battery and inverter might mean the inverter will do a low voltage shutdown.

I have a situation at my house where the wire I have buried is only good for 40 amps and I can now easily supply 50 amps at 240vac. There is a bunch of stuff in the ground along the path, so I will be very careful not to hit water or sparks if I dig a new trench, but the real scare is the price of wire, these days. Since the beginning of the year, the wire that I need has jumped to $902! Whoa!

Now, mind you, that’s for copper wire. What if I check the ampacity of ALUMINUM direct burial cable? Turns out, that’s a couple of steps thicker (wire usually increments in 2 points), but the price is only $258. That sounds a whole lot better. I don’t like aluminum wire, but I may make an exception!

Ampacity tables are all over the internet. What I have run into with them is that some tables list for safe current capacity and not necessarily for code compliant or for the voltage level where you are working. Take a look at the rating for 12AWG and see if they say about 20 amps. If so, you have the right table. Make it a little thicker (smaller AWG number) for lower voltage battery runs. 10AWG is typical for solar panel strings and 00 or 0000AWG are typically used for batteries on big systems.

As for my situation, to dig or not to dig? One of these days. Maybe.

Various and Sundry Items

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I have not forgotten you. I’ve been upgrading my own system, while hot rodding one of my solar powered electric farm vehicles, getting Turbo Beast stuck on archæology expeditions, cleaning up hurricane debris and goofing off when possible. I have another kilowatt of solar connected and 1500 watts more waiting for a mounting rack. The 12kw inverter set is connected to the transfer switch to the house, leaving the old inverter on standby. The new batteries are working out well.

One of my electric farm trucks is based on a Yamaha G19 golf car. For the record, it is CAR, not CART. Legal definition. Honest. Anyway, the little truck has always been a little low and has been prone to getting sticks jammed under it if you run over them. We normally have plenty of sticks, but with last summer’s hurricanes we have an overabundance of them, not to mention fallen trees by the hundreds. I don’t run over sticks, but unnamed others do. This rips all the wires out of the bottom and the vehicle is no longer useful. The wiring is peculiar in golf cars and most of it has to be intact for it to run.

After the last stranding, I ordered a lift kit to get the bottom out of the sticks. Then I needed 23″ Mud Crushers on 10″ mag wheels. Sticks don’t bother it, now. Mud, either. It is fitted with a new 3000 watt pure sine inverter, so I can run the big electric chainsaw and all of the woodworking tools. I’ve had it with gas saws and sorry gas. So I am doing some cleanup logging with the Yamaha, cutting sawmill size stuff and firewood. Oh, the car got some heavier springs so I can carry 1000 lbs of firewood. It will be getting a new body and revised truck bed, as well.

You’d be surprised what you can do with a small electric work horse like this. It is great for shuttling trailers, hauling firewood, providing power to remote places and just having fun. All the local donkeys, Fred, Molly and Hector, recognize it and come to their fences to beg carrots as we go by. Best of all, I plug these contraptions into the solar and I don’t have to worry about sour “gasoline” causing valves to stick and pushrods to bend, like on my mower fleet. In fact, I’m trading for an EZGO, tomorrow, so that will eventually bring the electric fleet to 3. A friend got it and wanted to convert it to gas and I had a gasser I wanted to run electric, so we are swapping.

I can plug these directly into the 48v solar power system or I can plug them into a charger from the 120vac. Think about, though, a full size electric car or pickup. All the manufacturers are proclaiming a date by which they will stop making gas cars. Where is all of this power going to come from? I just saw the specs for the new electric MINI, which is small in capacity. A 120 plug in will charge at 2%, or a bit over 2 days to charge the thing from empty. A Tesla or Rivian might take a week, but at that rate you probably would not over tax a typical home solar system. I think the total rush to all electric cars is going to cause some new problems. AND opportunities.

The future of grid tie solar is looking really iffy. Some power companies offer net metering and that makes grid tie a good investment. Some companies started with grid tie or pretty good deals and changed the deal after everybody made the investment. The latest dirty deed is a proposal–it hasn’t happened yet– to allow grid tie, but you have to pay a $90 monthly service charge. 3 companies, at least, in California are pushing this and California has mandatory solar required on new houses. That would guarantee the power company a minimum power bill of $90 a month whether you used any or not. Never fear, hybrid and Zero Export Grid Tie are here! I’ve discussed these before and will do so again. Of course, you can always go off grid! Are the power companies facing an exodus of customers? Well, look at how many ships are registered where they don’t have high fees. Look at high tax states that are losing citizens to lower tax states like Texas and Florida. The power companies might find that they are no longer needed!

Now if you were looking for some nitty gritty solar how-to, that is coming soon. We’ve been gathering details of a system Bruce in PA (I think that’s really his name) built some years back. It has some special considerations with high pitched roof and snow loads.

It looks like I will be recommissioning a system I shut down last year after the owner died. The new owner wants it running, but we are going to have to get creative to make it work on his battery budget. We’ll discuss some of the requirements and options.

And on my own project, the price of the copper cable to get the higher output to the house has soared 50% to over $900 in the past two weeks. We’ll discuss ampacity and various wire choices for tightwads, like me. Stay tuned.

As far as Turbo Beast and archæology go, I’m using lidar topography mapping to take a new look at a mill survey I helped with back in the 90s. Growing up I never knew we had water-powered mills in flat Florida, but there were loads of them, dating back to the 1700s. And I am on the hunt for old cemeteries. The loggers are chewing them up and they are being lost. Many of the mills and graveyards are related and well beyond the asphalt. Dodge’s version of Positraction simply isn’t very good, though, and I got stuck twice on the last outing. My Chevy is much better, but it is not equipped with Mud Crushers. I’ve backed the 4wd Nissan D21 out of the barn and it may return to service. Just what I need…another tag and more insurance. At least my fedora and boots are in good shape and ready for service in the field. –Neal

Baby, It’s Cold Outside

• Posted By : Neal Collier
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(I wrote this in December and somehow it did not get posted until April!)

This morning it was about 50 degrees. Tomorrow morning we are expecting 28. The constant temperature swings make it difficult to dress. Layering is the key.

Temperature changes affect your solar power system, too, particularly in battery charging. Is there any action you need to take? Depends.

Lead acid batteries, sealed or flooded, need a higher charge voltage in cold weather. If your charge controller or inverter/charger has a temperature sensor that sticks or bolts to your battery, you’re maybe ok. And when I say battery, I mean the total pile of cells, not just one casing holding one or more cells. Ideally, they are all behaving the same and have about the same temperature. You won’t have a sensor for each one. It doesn’t hurt to spot check them all with an infrared thermometer once in a while to be sure.

Only one of my many charge controllers has temperature compensation, so I have to do a little manual intervention as the weather changes. It takes a while for tons of lead to cool down. Longer if you have an insulated battery box or cabinet. I don’t.

I go out to my Man Cave/Control Room most evenings to watch movies, read or work on projects, so I keep up with the meters. Lately they have been running a little low. I have a temperature chart for my batteries and it shows my settings are a little low. I just bumped up the charge voltage to 59.9 volts for the highest setting, maintaining the float at 54.4. At some point, my inverter complains of too much voltage, so I go with the minimum settings. I can hear the golf car batteries sizzling in the jalopy in the afternoon, but the main bank is holding higher at night, keeping my hand away from the grid switch.

It is a delicate balancing act. If I boil the AGM bank I will kill them. If I run them too low, I shorten their lives. If I switch to the grid, what’s the point in having solar?

The system is getting an upgrade. I recently acquired my own mobile solar generator trailer, similar to the one in the Turbo Beast blog. It has been interesting to explore its wonders and integrating its components into my home system will be a big upgrade. The mobile system has a Midnite Solar MPPT charge controller, a pretty nice charger, but the real star and boss of operations is a pair of 6048 Sunny Island inverters.

It appears that all charging runs through the SI pair. It keeps up with State of Charge and controls an automatic diesel generator. The other night I forced the battery down with heavy loads. The generator started and before it was over the battery voltage had soared to 62 volts! A previous run had gone to 60.8 volts. The difference was the temperature. These are flooded forklift batteries on the trailer and have different needs than the AGMs in the Solar Shed. I will have to change the settings when the Sunny Islands and the Kubota genset are attached to the Shed, but then it will all be automatic.

I do not offer any settings or charts for you, here, because batteries are not all the same. These days you can find detailed data sheets online for most batteries. If you can’t find one for your particular battery, try another brand of similar type. For example, a generic golf car battery like the Sun 230 has specs similar to a Trojan T105 or Energizer GC2. My big AGMs were marketed for standby use and had no specs for cyclical use, so I had to borrow data from another brand.

I do not recommend mixing battery types, but I do it myself. I am evaluating a big pile of AGMs for the Solar Yacht project, I have flooded batteries in my electric farm vehicles and, soon, I will add the 2 tons of forklift batteries from the mobile unit. In this case, the AGMs are the fussiest and most expensive, so I will go with their settings and pull the flooded batteries off to the side from time to time to give them a desulphating charge that would kill the AGMs.

If you put your own system together you should know if you have temperature compensation built in. If not, ask your installer or do a little snooping. A temperature sensor cable usually plugs in or screws to a terminal block marked something like “temp.” All that I have seen have used a thin round wire or flat cable, similar to “modular” cable used on real telephones. Remember those? At the battery end the sensor will be embedded in a piece of plastic that sticks to the battery or in a ring terminal that connects with the battery cable.

Yes, the shorter days and winter gloom could be hurting the performance of your system, but it could also be something as easy to change as a charge setting. When in doubt, read the manual!–Neal

Stephen is Thinking Solar

• Posted By : Neal Collier
• Technical Blog
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And 2000 pound monsters.

I got this comment from Stephen. I’ll let you take a look at it and then I’ll comment, OK?

“Well I’m a new-b, & an old fart, I wanted to start this process a long time ago, but for the dollars…
I’m interested in learning more of the availability of these 2000lb. Monsters, though I really need some education on the basics like …If I Install 11,500 watts of panels on my clear view roof, do I need to buy ( 3) 4048 inverters & then split the panels over 3 separate systems?? Sometime in the future I may purchase a nice 20kw diesel standby gen. w/ ags. Probably will take a while $$$again.”

OK, here we go. No worries about being new. Every day is a new day with solar. Every morning I read a half dozen or more solar and energy newsletters and there is always something new. As far as being an old fart goes, Old Guys Rule! Step away from the rocking chair! And as far as the $$$ go, you are already ahead of the game if you’ve found Sun Electronics. I look at some of the pro systems going in around me and OMG the prices! My system will blow most of them away at a fraction of the cost.

Now, you ask about “2000 lb. Monsters”. I assume you are talking about my forklift batteries. 540ah at 48v is a good start and I figure 4 of them will put you in good shape. However, there’s that 2000 lb. bit to consider. The more modular battery systems are easier to handle and many require little or no maintenance. The forklift batteries can be a super deal, though. Probably the best ones are coming off a 2 year lift truck lease. For some reason, these leasing companies pull the 2 year batteries and install new. You can find these on Ebay. There are forklift companies and battery companies in most cities and they can be a source. It could be good to buy locally and cultivate a relationship because your battery may need service some day. THEY can change a cell or rejuvenate a tired battery, but I don’t think they do house calls. Maybe, though. There is a funny numbering system for these monsters that tells you the volts and amp hour ratings, but you have to know the code. And since we are talking about batteries, I assume we are not talking about grid tie.

Grid tie can be quickest and cheapest to install, but most folks like having their lights stay on when the grid goes down? I hear that happens. You can still have the grid and run it in with the solar in a hybrid, interactive system so you can avoid fees and all manner of unpleasantries that some power companies impose.

I’m not sure how, but somehow you came to the conclusion that you want 11,500 watts of solar panels on your roof. That’s actually a pretty good number for a typical American home. That’s over 200 amps of current in a 48 volt system, so you need a pretty hefty battery bank to soak it all up without causing problems. You note you have a clear view from your roof….to the south? That’s great for maximum production, but we are finding that it is actually pretty good to have some panels facing the west. I know my a/c is running in earnest late in the afternoon and the sun is toward the west at that time. After success with a small experiment, I am putting in a 10 panel array in a westerly orientation. North is not a good direction, but pretty much everything else will work.

Next you mention 3-4048 inverters and I am not sure why. Because 3 x 4048 adds up to pretty close to that 11,500 watts of solar? That isn’t how it works. Your modules are going to connect in blocks of, say, 3. Those blocks meet up in Combiner Boxes, as appropriate, and all that combined electrical goodness goes into a charge controller. Most of these charge controllers I use have an input of 130-160 vdc. 3 panels in series, generally add up to that. There are exceptions, so check the data sheets and think ahead. I also have a 250v input charge controller that will handle 5 x 60 cell modules or 4 of the higher voltage 72 cell modules. In addition to those volts, you need to keep up with the watts, as well. A 60 amp charge controller is good for around 3000 watts. I say “around” because folks have different takes on how mathematics works. In my motley collection, the 60 amp controllers range from 2800 to 3200 watts. Some are more tolerant than others to the occasional aberration. Read the data sheet, watching for gotchas.

There are bigger charge controllers, like the FM300, but I kind of like the idea of having a little redundancy. I have 6 charge controllers on the main system, but 4 would be plenty. By now you have guessed that if you are using 3000 watt charge controllers, YOU will need 4 of them to cover all those watts flowing off the roof. Now, do as I say and not as I do, here…my system didn’t just happen, it evolved. I have several varieties of charge controllers, so they can’t share a communications system if you like to chuckle over charts and graphs of power production.

Now we have all of those solar watts tamed and being shoveled into our monster battery pack. Let me tell you about a fellow who fed a similar amount of power into a not-quite-monstrous battery pack of 400 ah. First, that was not enough to do much good on a whole house system. Second, cramming 200 amps into a small battery pack is just going to cook the batteries. He had some nice AGM batteries, but not for very long. 60 amps for the set should have been the limit. I have some AGM batteries of twice the size and the data sheet says don’t exceed a charge rate of 40 amps. I have 4 strings of those and the monsters and two electric vehicles to soak up well over 200 amps without exceeding the limit on the charging rate of the delicate AGMs.

Better still, a forklift battery or any other variety of flooded lead acid or FLA battery is pretty tolerant of a hard charge, though you might have to water more frequently.

OKAY, back to the 4048 inverters. You apparently broke the code, here. 40=4000 watts and 48=48 volts. Why 3? What you need to consider for inverters is how much do you need? Being careful, I have run everything but the electric stove and clothes dryer, including one of the central a/c units with a 5048. I don’t have an electric water heater. At the present 10,000 watts I could pretty much run it all if I had a heavy enough cable. (That’s a project for another day) My old partner, Tom, did well with a 12kw inverter. Then it broke and he ran, I think, an 8kw, one of those nice Outback GS units that Roberto has. It was not quite enough, but you can run two of them in parallel for 16kw, so he was in good shape and if one failed he could get by while repairs were being made.

There are myriad features in today’s hardware. Many 4048 inverters I have seen, like the old Xantrex or Trace or Sunny Island are 120 only. You connect two with a combiner to make 120/240 for normal household operation. I am presently cabling in a pair of Sunny Island 6048 units that work the same way. You gotta have two of them and 3 would be just weird. The combined 12kw would be overkill for me. Right now I use them for welding, so they are pretty tough. My homebuilt 10k48 puts out 110/220 on its own, but has no tricks. The Outback GS8048 makes 110/220 standalone and you can stack it to double the power. It can also do lots of nice tricks, like hybrid, grid tie or automatic transfer. The beauty of the 8048 over the smaller size is that you get twice the power for just a grand more.

Now what? How are we going to do this? I’ve mentioned some really versatile gear, so we have options. If you want to go off grid, you are good to go. If you want to keep the grid for backup or because you use a lot of power, how about a hybrid setup? This is especially handy if your power company hates solar (charges fees and makes onerous rules). The aforementioned Tom connected his inverter to the house through a transfer switch, like he used with his generator. The grid had a separate line down to the barn where it entered the secondary input of the inverter. During the day, and as long as his batteries were above the threshold he set, the inverter provided power to the house. On warm summer nights, the a/c would draw down the battery and the system would shift back to grid. There were no extra fees and no selling electricity to the power company for 3 cents and then buying it back at night for 13. His big limitation was his tiny battery bank. With 2000 amp hours, I suspect a changeover to grid would have been rare.

I have simplified things here, of course. You’ll need to throw in some surge protectors and circuit breakers. There are the mounting racks for the panels and the cables and gadgets to comply with the new “rapid shutdown” rules to let the fireman shut down the panels before spraying water on the roof, in case of fire.

Finally, a 20kw generator? Diesel is a great choice. Today’s gasoline just won’t keep. There are natural gas and propane units that may be a good choice, too, but I am a fan of diesel. I normally keep enough diesel and jet fuel around that I could run a generator for a year. Many years ago when we had a 5 week outage I had an old 15kw diesel that ran at 1200 rpm. It was meant to run continuously and had 3 phase. I brought 2 legs in through one of the external a/c disconnect boxes and ran the whole house. It came in through a 30 amp breaker, so I could only use around 7000 watts and we did fine. It would charge my battery backup, run the stove, laundry and water heater while I was getting ready for work and then we’d shut it down. (This was back when I was willing to work for a living.) Lights and fridge and such ran off the battery backup except during breakfast and supper.

So I guess the point is that 20kw is probably more than you need. My recent generator addition is an 11kw Kubota LoBoy with 113 gallon fuel tank and autostart. I can’t imagine needing more than that. Oh, and by the way, the smart inverter is taking that power and passing it to the house and/or charging the battery as needed. Boy, these inverters are smart, but the manual will blow your mind. You actually have to think, which I suppose is usually the best plan.

Did I cover it all? Get busy, Stephen!

-Neal

Does Anybody Have a Fire Extinguisher?

• Posted By : Neal Collier
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It is only natural to want to improve or hot rod your system. Know the limits, though.

Despite all the political controversy, Facebook remains a useful tool, especially the “groups” if you are into a special interest. I don’t have a FB account, but I hijacked my wife’s account to join a group of folks who also have the mobile solar generators, like the one I bought. (See TurboBeast story).

There is a wealth of information to be shared on such a complex combination of mechanics and electronics. Some people are very knowledgeable and some are total newbies. There’s lots of sharing and lots of creativity.

Let’s examine the system. There are 10 solar modules, 60 cell units from 230 to 270 watts, depending on build date. They are arranged in two strings of 5, meeting in a MidNite Solar (MS) combiner box and brought under control by a MS250 charge controller. The MS250 charges 4000 lbs. of forklift batteries, which may be flat plate or the newer tubular plate flooded lead acid batteries. The batteries supply a pair of Sunny Island 6048 inverters, which combine to output 12kw of 110/220 power. The Sunny also controls my autostart diesel generator, so I’ll have to try really hard to run down those batteries.

The 12kw output will easily supply most houses, I think. I’ve seen houses run on less. The weakness in using these rigs to run a house, though, is that they have only 2500 watts of solar and around 1000 ah of battery. 2000+ ah is working great for me. I have found the hard way that the recently revised recommendations for battery sizing are much more practical than the older assumptions. And more expensive, of course.

The 2500 watt solar limitation is pretty much a physical limitation. There are just so many panels you can mount on a 17′ trailer bed. Yet, since these were built, panel output has increased.

Courtney, for example, after consulting with me, replaced his panels with 60 cell 320 watt panels. That’s a 700 watt boost and he stayed safe.

The MidNite Solar charge controllers rate things a little differently than some others. Many show the output CURRENT in their names, like an Outback FlexMax 60 is rated for 60 amps or a FM-80 is rated for 80 amps. If you want to power the world, I think there is even a FM-300! But the MS250 is talking about volts, when it puts a number in the name. Whereas the FM is rated around 150v, if I remember right, the MS is rated at 250v. The difference affects how many modules and what kind of modules you can put in a series string.

With a 150 v limit, you’ll find that 3 typical 60 or 72 cell panels in series is a good way to go. They each have a peak output of around 36 or 46 volts, but always consult the data sheet or the label on the back of the module. On the Sunelect.com website you’ll usually find a datasheet download available. Yes, consult the sheet. I have bought some modules from Roberto that had 90 volt output. I just run those in parallel on a 150v charge controller.

With the MS250 controller, you can easily run a string of 5 60 cell modules, as long as you stay with in the power rating of the controller and the 320 watt modules do this. Then one of the guys, Mike, comes up with this: “I bought one with the panels swapped out for 72 cell, 370 watt panels. Nothing has burned up yet, but it has problems. The Midnite is in “hypervoc” mode most of the time, and screams like a banshee. I wouldn’t recommend it.” Mike lives life on the edge.

The problem is that he has exceeded both the voltage and current ratings of his MS250 charge controller. That it is still running is a testament to robust design, but I suspect that controller will live hard, die young and leave a charred corpse. Which reminds me, do you have a fire extinguisher around your system? Mike admits that his charge controller is literally hollering about its working conditions. The proper way of doing this upgrade would be to add an additional charge controller. He’s about to buy a new one, anyway! Or two, if he wants to put it right.

Dale had another solution: Leave off two of the panels, which would defeat the upgrade, “Or, wire the two left off panels in series, straight to the battery? What could go wrong overcharge the battery if there’s not much load on the system, but otherwise maybe ok. One 72 cell panel wouldn’t be high enough voltage to charge the battery”

OMG, NO-OOOO! It might actually work, but if you left it unattended for a while you could boil out the batteies, which I think run around $5-6000 EACH. You’d also miss out on that MPPT goodness that a quality charge controller can provide.

I guess what this comes down to is think creatively, share ideas with others, ReadTFManual, and keep a fire extinguisher handy.

–Neal

Batteries–Bigger is Better

• Posted By : Neal Collier
• Technical Blog
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Sometimes bigger really is better.

It is raining, today. What to do? I’m in the middle of a huge upgrade of my solar power system, but most of the work will be outside and I don’t care to get wet. Wet, as in a hot tub is ok. Being cold and wet does not appeal to me.

I guess I can water batteries. It is time for some of them. In my various independent and blended systems I have a lot of cells that are AGM and don’t require water. I also have 168 cells that do need to be watered. This is nuts, but it is just the sort of thing that can happen if you start small and gradually grow the system. Things can get out of hand.

I recently acquired a couple of forklift batteries in the Mobile Solar Generator trailer I bought and I am impressed. Mine had been serviced, but another set belonging to a friend had not…for over 4 years. They still had water above the plates. Granted, we had to add 12 gallons to top up, but if they can go 4 years without being damaged, getting overlooked for a month will never be a problem. In fact, these are designed to be checked every 3 months in heavy service.

I started off with so-called golf car batteries. Exide calls them electric vehicle batteries, which I like as a better term. Many people refer to GC batteries as “starter” batteries. Not in the sense that they are used for starting a vehicle. More like in the sense of training wheels on your kid’s bike. I resent that term, but I suppose it is true.

Many people use GC batteries, like the Sun230 that Sun Electronics sells. That’s all they need or that’s all they can afford. The difference between a Sun230 and a Trojan T105 or an Eveready or Exide GC2 is basically the price. The Sun230 is cheaper and has a few more amp hours. Also, you buy them from Sun Electronics, you pay no tax and need no core. Florida exempts solar stuff, but try telling Sam’s Club or WalMart that. Starter batteries? Fine. You gotta start somewhere.

If you have a big budget, then by all means think big. It can save you in the long run. That’s the big holdup on solar, though, isn’t it? You can get electricity from the PoCo for $250 per month, whereas the sun’s free electricity might cost you $15,000 or $50,000 more up front, unless you do-it-yourself. I heard from a guy the other day with a $350 power bill and a quote for a $130,000 power system. I understand why folks start small. I started small, actually intending the system as a test bed for stuff I was doing with my solar boats. It just got out of hand, after a while.

So what’s the difference with the bigger batteries? For years, the L16 was the battery you aspired to have. Some scrounged them from floor scrubbers and some bought retail. Comparing to a GC2, the L16 is a lot more expensive in $/amp hour. They may be cheaper in the long run, though, because they have thicker plates and hold more acid. Thicker plates generally equate to longer life and more liquid means you are less likely to get low and ruin the thing.

My first visit to Sun’s old Miami warehouse was a hoot. Oh, the new store is nicer, but I don’t think it has the character of the old place, especially when the grafitti artists had been at work. In the showroom there were these huge Rolls batteries. Actually, they were hollow demo dummies, but huge all the same. Just 2 volts, but lots of lead, acid and amp hours if you got the real thing. A hand truck is required to move them, the real ones, not like the featherweight 64 pounds of a GC2. Put 24 of them together to make 48 volts and you had serious storage and longer life. Also, you only had 24 cells to water, as opposed to scads of them for the same power in a stack of GC2s.

The big 2 volt scheme is pretty good, I think. They are still hand truck portable, yet retain the advantages of scale. My new batteries are 510 ah at 48v (8 hr. rate) and weigh a ton each. It’s like a set of the semi-portable Rolls cells soldered together in a steel box. Actually, though they are new to me, they are 5 years old, which in big battery life is just broken in good. They are not very portable, though. My big tractor might lift them, but it is out of order. The smaller tractor will not. Getting them off the trailer was easy enough with a chain fall and an oak limb. I used old tech and sledded them to the Solar Shed. There is not much room to maneuver behind the shed, so the wimpy tractor is little help. Jacks and cleverness prevailed, though.

At my friend’s house, he has stripped 2 of the solar trailers. He has a better infrastructure setup. He offloaded with an I-beam and trolley setup, then used pipe rollers to move the batteries through the garage. He is starting with 2160 amp hours of battery in his new system. That is super for a house his size. At a ton each, the batteries are still moderately portable, given his circumstances. I hope the garage doesn’t settle on one side and tip over.

In Texas, where everything is bigger, one of our correspondents shared photos of his 800+ ah Bulldog battery (if I remember right). Now that was one big battery and he has a forklift and a trolley to move it.

I’m starting to ramble, I suppose, but the point is, the more battery you have the better your system will perform and the longer the batteries will last. If you use large batteries, instead of lots of little batteries, they are likely to last longer and require a lot less maintenance.

As for my upgrade, with over 2000 amp hours of storage I am easily rolling through multiple cloudy days without hitting the dreaded 50% depth of discharge. 10 more solar modules are waiting to squeeze a few more watts out of the clouds, too, but the huge reserve seems to have solved a lot of issues. I have also added an automatic diesel generator, just in case, but so far it has only had monthly exercise run time.

–Neal

Neal & Turbo Beast’s Big Solar Adventure

• Posted By : Neal Collier
• Technical Blog
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Buying prefabricated mobile solar power plants at auction and quickly spiriting them away.

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It Pays to Know Your Stuff

• Posted By : Neal Collier
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Some people build their own solar power systems. Some people pick up the phone and then write a check for theirs. It’s ok, either way, but I advise that you at least have a basic understanding of how things work.

If you have to ask why, I can give you a recent example from my neighborhood. It isn’t what a lot of people would call a regular neighborhood. It is nearly a mile to the nearest corner and 4 miles the other way. There are only 7 houses located along the road and nearly twice as many of us live as much as a half mile or more out in the bushes. I don’t think any of us know all of the neighbors. After 30 years here, I’ve gotten to know a few. In fact I think I am in 4th place to become the Old Timer. Miss Christine is 92 and holds that title, for now.

I met the newest neighbor, Brad, last week. I’ve met most of his friends and contractors because a GPS quirk sends them all to my house. That’s how I knew he was getting solar power at his place.

Well, someone who has solar is always interested in keeping up with the Joneses, or the Brads, so I stopped in to meet him the other day when the power lines were down, again.

Oh my! What a system he has. It has some interesting quirks to it, cost a fortune and it doesn’t work!

For some background, Chuck lived there during the last really fun hurricane season, about 15 years ago. The FIVE WEEK power outage prompted Chuck to get a very large propane Generac and a fuel tank to match. Fast forward to 2020, when everything else has gone wrong, and the reported $850/month power bills prompted Brad to add solar.

Now, I don’t know a lot about Brad or his house or his lifestyle, but I suspect that anyone with an $850/ month power bill has a certain amount of potential for conservation measures. Just sayin’.

Back to his system, there are about 27 kilowatts worth of shiny new LG panels on the roof of his 5 car garage/shop structure. It is a great roof for solar, except it faces to the west. I’ve been telling you that solar isn’t just for southern exposure, anymore, but a strictly western exposure is not ideal. On the other hand, the roof of his house is very steep and is full of crazy angles. I’d have to go along with the shop roof placement. BTW, close proximity to a wall of pine trees ruled out putting half of the array on the east face of the shop.

The array is set up for grid tie and that is where the problem lies. I have mentioned more than once that our power co-op hates solar. There are companies, like his installer, that have mastered the power company paperwork and folks like Brad who are willing to put up with the extra fees and unfair billing practices. However, that still does not mean that the power company is any rush to sign off on the connection. (Read some past blogs to find ways around this.)

The thing I don’t like about grid tie is that there has to be a grid to which you tie. On the day of my visit, the grid was down, post Hurricane Zeta, so it hardly mattered that he didn’t have grid tie. Somewhere along the line many solar owners decided that they wanted to keep their lights on when the power company couldn’t. There are several ways to skin that cat and in Brad’s case it was manifested in the form of three Tesla Powerwall batteries.

The Powerwall is a neat gadget, I’ll give them that, but it is pricey. According to a recent article I read, they recently increased the price from $5500 to $7000. Each! It is more than just a battery in a compact box. You have some electronics in there, too. Still, for a fraction of the cost of ONE of those Powerwalls, Roberto can fix you up with the makings of a decent little back up system for your house.

Back to Brad, though, here he has these batteries and all this stuff ready to go, but his lights were out, too, like most of the other neighbors. All because the power company doesn’t like solar.

Oh, wait, what about that big Generac? Remember, it is still 2020. It was great after Hurricane Sandy. It kept the lights on for a while until the 15 year old propane regulator failed. The inrush of excess gas blew the exhaust system off and the overspeeding motor smoked the control board. He couldn’t get parts before the next storm came.

So now we get to my Know Your Stuff admonition. There is a big gray electrical box with a big red handle in the OFF position. I strongly suspect that moving that handle to the ON position would have turned on the lights. There may have been more to it, but I don’t know Brad’s stuff. Let’s just say that would have worked. That still would not have been a great idea because the system is set up for grid tie. When the power came back on from the co-op, his system would have gone into the forbidden grid-tie mode. His smart power meter would have phoned home and ratted him out and caused more strife with the company that controls the fate of his system.

Let’s look at another scenario. Let’s say that Brad had observed, asked a lot of questions and read all of the manuals. Let’s say that Brad knew his stuff, all that fancy new hardware. He would have known for certain about the big red switch and would have known how to turn off the grid tie mode so the meter couldn’t rat him out. He’d have had solar power for lights, fridge and MR. COFFEE. (A survey of several neighbors, post storm, put powering the coffee machine ahead of keeping the fridge running.)

Brad will eventually get his Generac repaired and the co-op will run out of excuses and sign off on his connection. He’ll have the finest, triple-sourced power system in the area. Life will be good. Take a lesson from Brad’s experience.

Take the time and get to know your stuff. It will be worth the effort. –Neal

I’ll Bet the Neighbors Wish…

• Posted By : Neal Collier
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When it is raining buckets and the wind is howling, it is very comforting to have the lights stay on when the power lines go down.

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Where the Politicians Stand

• Posted By : Neal Collier
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You may have noticed that it is political season. What have the politicians personally done for solar?

Jimmy Carter put solar-thermal panels on the White House roof. They came down the next time the house was reroofed, though they were still working. One is in the Smithsonian and another is in a science museum in China!

Bush 2 put solar on the White House, again, as did Obama. What? Did Obama add some or did Bush’s come down in another roof repair?

Former VP Al Gore, Mr. Global Doom himself, claimed his mansion was carbon neutral because he invested in green energy and bought solar energy credits that added a paltry $432/month to his power bill. He even bought some CF bulbs! To his credit, he has added 33 solar panels since then. I wonder if he has switched to LED bulbs?

What about all those other politicians out there? There is a web site that examines rooftops to find out where they stand. Check out https://solarpowerchallenge.com/ to see where they stand! Use a satellite app to find more rooftops.–Neal

PS–Spoiler. Neither of the presidential candidates appears to have solar power on their personal abodes.

Miscellany

• Posted By : Neal Collier
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Oh, will they ever come up with the perfect battery? Super capacity? Super cheap? I’ve met one guy who has learned to adjust his pace to make it from Pensacola to Miami in a Tesla. Maybe adopting a more relaxed pace would be good for most folks! Solar Jorge, down in the Keys, likes the discontinued Chevy Volt. You can do your daily commute on electric and charge it with solar, but if you want to run coast-to-coast, there is no problem. In the meantime, let the photo above be a warning. Oh the irony of that bumper sticker and the Honda generator! Sad truth is, the car is probably normally charged by coal generator unless he has his own solar power system.

I am constantly messing with batteries. Adding, upgrading, experimenting, trying to coax a little more life from them. The set of 8 T-105s that I repaired by installing new studs have been added to the battery zero export grid tie system. Most of the house is now off grid, now that the demands for a/c are down and my battery pile is higher. Still, that ZEGT system chips in some sun power when the dryer or oven are running.

When there were no batteries the system was constantly tripping out as the two inverters fought and passing clouds would interrupt the flow. Adding 230 ah of Sun’s house brand batteries helped, but with the high draw of the dryer the inverter would soon trip out at the low end of the battery range. Granted, the trip point was set high for longer life, but adding 220ah of Trojans made a lot of difference. I took a look at the meters this afternoon and each leg was contributing 850 watts. These are “1000” inverters, rated, of course, at 950, actually running at 850. Chinese math. Still, running the dryer with 3300 watts from the utility is better than running it with 5000. The batteries are backed with 2kw of panels and I was registering a real 1750 watts coming out of the charge controller, this afternoon. Not bad. This should be a good setup for summer use when much of the house is on utility power. As is, I could probably drop down to 1 kw of solar.

I had another couple of stray solar batteries. I don’t think Tony and Roberto sell the Outback 106RE batteries anymore, but I had two old ones out of a set of 12 that tested 100% after 5 years of overcharging. What to do? I need to restore the barn solar, so maybe one there to run the lights. It would be nice to have more for tools, but we can always plug into the jalopy for kw power.

And the other? In the wake of the hurricane, my last two running tractors abandoned that classification. One of them decided the fuel injection pump had pumped enough, so I am awaiting parts from Ukraine. BOTH had batteries die, along with the one in the wife’s car. Batteries always seem to start crashing with the first hint of cooler weather! I wondered about the use of an Outback 106RE for starting a Diesel tractor. One way to find out.

In my recent studies of AGM batteries, I learned that while you cannot charge them very hard, they have insane discharge rates. Would a 5 year old abused battery have enough insane discharge to start a Diesel? Yup. I had to change one cable terminal and it worked great. That tells me that surge power to run an inverter should not be much of a problem.

And speaking of surge power, I was rummaging in the Sunelec.com web site and found an interesting new battery system. It looks awesome, in a neat rolling cabinet. 4 of those would look good in my Man Cave. They are too pretty to put in the battery room. I think the bigger unit, the lithium-based eVault Fortress, can put out around 170 amps, so it would be a good match for one of those GS8048 inverters and around 5kw of solar. It gives both the input and output specs, so it is easy to make sure you are matching the inputs and the outputs. You can stack them for more power.

To replace my current battery pile I would need at least 4 of them. Maybe John will send 4 of them to me for a test drive so I can write a review. I won’t hold my breath!–Neal

Saving a Battery

• Posted By : Neal Collier
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If a terminal is broken or melted on a battery, you may be able to save it with a simple fix.

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$7 Panel Update

• Posted By : Neal Collier
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Why not cover a carport with $7 solar panels?

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Aftermath

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We take a look at post-hurricane emergency power after Hurricane Sally.

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Torque

• Posted By : Neal Collier
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I recently had to burrow into the entrails of my new 21 year old truck’s transmission. It is sort of a rite of passage with the old Dodges. Specifications for putting the various pieces back together are very specific. I remember what my little brother did to his Plymouth’s transmission 45 years ago and I didn’t want it to happen on my Dodge, so I bought a new torque wrench. I had one I bought 50 years ago, but it was built for many foot pounds and not the inch pounds required of delicate transmission in the 6000 lb. pickup. The new 1/4″ drive wrench set me back around $20 at America’s favorite Chinese tool store. I didn’t have a coupon.

Having successfully reassembled the transmission, I set out for another load of batteries to evaluate for the Solar Yacht project. Another few hundred amp hours never hurt any battery bank.

These are my biggest batteries yet, but they have the smallest bolts, yet. It uses M6 bolts…less than 1/4″. Most of my others use 5/16. Batteries with just a hole in a post are not terribly worrisome. If you overtighten and break the bolt you just put in another. If you overtighten a top stud battery, like GC batteries, you can pull the stud out, which starts to be a problem. My recent additions have bolts that go into brass inserts in the case. If you break off a bolt you have a real problem. If they are large enough, you might be able to use an extractor. My view of the extractor is that it is a noble thought, but generally not very useful.

The key to not worrying about this stuff at all is to use a torque wrench set to the battery manufacturer’s spec. Do so and the terminal will be tight enough and you won’t break it. I think I set mine to around 80 inch/lbs. for the M6 bolts. Just set the dial and pull on the handle until you feel it click. No worries about too tight or too loose.

I don’t plan to go back into the transmission, anytime soon, so the torque wrench and appropriate sockets will live in the battery room with a few other tools that are commonly needed.–Neal

I Don’t Know What It Is, But I LIKE It!

• Posted By : Neal Collier
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Every now and then you need to tidy up a bit. I’m bad about that sort of thing. I needed to take a truckload of batteries up to the recycler in Atlanta, but the Chevy just won’t carry enough. Then I inherited, sort of, a Ram 2500, which can carry an additional ton without any problems.

I loaded up and got on the computer to plot a course to the recycler.  The GPS course used the interstate, which is scary to a fellow who has to drive 4 miles to find a stop sign.  Most of the interstate, say between Mobile and Newnan is not scary to me.  But when you get to the outskirts of Atlanta, it just goes crazy.  They don’t have cloverleafs show up on the GPS map, they have spaghetti bowls on display.  I don’t know if their highway designers are geniuses or just plain nuts. 

Using satellite images of the area, I came across the strangest thing.  It was a huge building, though from overhead it looked like an alien vessel, just arrived on our planet.  Better yet, it was festooned with solar panels.

Hey, if you are going to do solar, why not be awesome about it?  I was eventually able to determine that this is the National Archive at Atlanta building.  I spoke with a guy who lived nearby and he was familiar with the building, but he’d never seen an overhead view and nothing on the ground gives a clue.

Georgia has a lot going on with solar.

–Neal

Don’t Be a Post Hurricane Statistic

• Posted By : Neal Collier
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It makes me mad to see that people die after the storm. You buy a generator to keep the lights and fridge on, but the thing can kill you. Here are some thoughts.

First of all, have a battery backup system in place.  This can be a building block for a future solar power system or it can be a quick solution.  More on that later.

When you buy a generator, also buy a length of stout chain and a padlock.  People steal generators and that is why their owners put them in the garage.  Running a generator in a garage that is attached to the house can lead to carbon monoxide getting into the house and killing you.  Don’t do it.  Chain the thing to a tree or car and let it run outside.

Have lots of fresh gas and oil before the storm.  You won’t be able to buy it for days because the pumps won’t run and neither will the credit card machines.  Store the gas in a safe place in sealed plastic containers.  Any thing not sealed and the gas will go bad quickly and it can ruin your generator.  Bad gas in my 22 hp lawn mower just caused a stuck valve, which pretzeled a push rod.  (See image above) You can’t buy engine parts after your town has blown away.  Treat the gas with Stabil, Sea Foam or Marvel Mystery Oil.

Note, too, that most small generators need the oil changed frequently.  25 hours if it does not have a filter and 50 hours with.  Don’t buy a used generator after a storm…they probably didn’t change the oil.  After you are finished with the generator, let it run out of gas.  That nasty stuff they sell today destroys carburetors.  Change to fresh oil so you are ready for next time.

A whole home natural gas generator is a thing of joy, but expect a whopping gas bill.  Mom spent a bunch on hers and never regretted it.  Her neighborhood got trashed by a tornado a few years back and she was the only one with lights  and a/c for days.

Don’t refuel when the engine is hot.  They can catch fire and blow you up.  And burn down your house if you are doing this in the garage.  You’d think it a simple thing to put the spout in the hole and not spill anything, but a full can is a bit unwieldy at 30 lbs. and those !@#$% worthless government-mandated spouts make it worse.  I broke two of them before I mastered getting the gas out.  You can buy bootleg good spouts, but they cost more than the whole gas can used to cost!

Here’s where your battery backup system can shine.  At night, it is quiet and not making fumes.  You run the generator intermittently at an efficient load to charge the batteries instead of 24/7 buzzing to run light loads.  You will use less fuel. 

Your car can be the generator.  Yeah, your car.  After one storm, I was loathe to drag my monster diesel generator out of the barn.  When I say drag, I mean drag.  It weighs thousands of pounds and is on skids.  Getting it out with a tractor is easy, but putting it back is a pain.  For 3 days, until I knew the power was seriously out and would remain so, I traded generating duties between an F250 and a Chrysler LHS.  There was a 2kw inverter connected to the battery.  I would run them intermittently to keep the fridge cold and a few hours in the evening for lights and TV.

That same storm, my bro had a Rubbermaid tote box full of golf car batteries and an inverter on the balcony of his town house.  His Chevy and a length of SEU service entrance cable topped them up.

I hauled a load of scrounged batteries and an inverter to Mom’s place and connected them to her minivan.

My later Chevy pickup was fitted with a forklift plug on the front so numerous accessories can be used, including a 2kw inverter.  The Dodge Cummins pickup I recently acquired has two huge batteries, huge cables and a huge fuel tank.  I have plans for it.

With just the addition of the inverter, your vehicle can be your power plant.  Better yet, call Roberto at Sun and he can set you up with a simple standalone battery kit or a fully automatic setup that will switch power to the whole house.  Lots of his customers live in places with unstable power, so he has kits for various situations and budgets.  The bigger systems won’t be 12 volts, chargeable by your car, but they will be the first step in a solar power system.

Oh heck, why not go solar?  Or maybe you have.  In the event that the storm might blow away your solar panels, you might consider putting a few under the bed, just for insurance.  We still have some time left in this storm season.  Get prepared.

 

 

 

 

 

 

Still Looking…and Finding

• Posted By : Neal Collier
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When adding an upgrade to your solar power system, consider what other components may need to be upgraded as well.

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Deconstructing a Solar Power System

• Posted By : Neal Collier
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A widow has asked me to dismantle her 4 year old 10kw PV system. It isn’t that she didn’t like solar power, but she has to sell the house now and mortgage inspectors are brutally thorough and her husband had overlooked the business of permits when he installed the system. In the process of going through Tom’s system I am finding some things of interest. Here are the good, the bad and the ugly.

First of all, his original installation featured 200 amps of solar power and 180 amps of charge controllers. You should know that a 200 amp solar system will rarely crank out that much, but sometimes it does. You should also know what you have in terms of gear. The first MPPT charge controllers were 60 amp controllers and, by golly, that’d better be all you run through them. One still works. The first one that went bad was replaced with a Flex Max 60. Still a 60 amp controller, but it just limits the output and won’t hurt itself. After the second original charge controller smoked, he finally heeded what I’d told him about underspec’d charge controllers and overdid it, buying two of the FM80 units. That’ll darn sure handle it, but another FM60 would have worked because of the current limiting feature. It may be that he just bought the FM80s and put the FM60 in reserve for the day when the final Brand X controller expires. Anyway, read the manual (RTFM) and sometimes you can save money by not buying too small and sometimes by not buying too large.

Now here is something I like. He made his own cables and with 2 cable ties and a strip of inner tube rubber made what effectively serves as boots. You can still easily get to the bolts, but if you drop a tool, you are less likely to short anything out.

These Trojan T105s are only two years old, but the water was never checked. Ever…until it was observed that the system just wasn’t performing up to snuff. Normally, if you dry out a set of batteries, you get fuming acid toward the end, and even early on you can get some really corroded terminals. Lots of people use Vaseline or ordinary grease on terminals to help with this, but Tom used an anti-corrosion electrical grease, and boy does that stuff work! These terminals are all bare copper and there was not a hint of corrosion on any of the 16 batteries. I don’t have a brand for this, but will be checking on it. No more axle grease for my batteries!

I have harped on keeping the batteries watered on many occasions, but that is not the only battery maintenance you need to do. By the way, when the batteries were topped up with MANY gallons of distilled water, the cells were all active and they regained 50% capacity. That’s says a lot for Trojans. I suspect a good desulphation charge will do wonders for these batteries. Worth a try, anyway. But back to the other battery maintenance chore. You have to snug up the bolts to make sure they stay tight and resistance stays low. What happens when there is resistance? Power is wasted in the form of heat. Fire up the a/c and the dryer and you’ll find out just how much heat. Near the top left of the next photo you can see what a T105 terminal is supposed to look like. Then there are two that were a bit loose.

All of the nuts had washers under them, but none were lock washers. Lock washers serve two purposes, they can keep the nut from backing off, but they also provide a little spring tension. What I like best for batteries is the Belleville washer. This is dished and provides great contact pressure without over-tightening the nuts.

I don’t mean to trash Tom’s system, but it is always good to pay attention to what you should and should not do and observe the results of both. Looking at my photo of a ruined $150 battery is a lot less heartbreaking than have it happen to yours!

It just breaks my heart to turn off a working system! –Neal

Look West Update

• Posted By : Neal Collier
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I have been observing the performance differences of my west wall array and my conventional south arrays. Arrays still pick up a lot of power under cloudy conditions, but the south arrays are doing better. I think I know why.

The current situation is that the west wall will do pretty well with direct afternoon sunlight. However, it is pretty much facing a dark wall of trees, which reduce diffused and reflected sun from the western sky.

On the left of the Solar Shed, the arc of trees between the edge of the airstrip and the red line blocks the view of the sky.

If I cut some trees in that arc, it should brighten up those panels on the wall. The ground falls away very rapidly to the west, so it won’t be very many that have to be cut. Maybe a half dozen are the principal offenders.

It’s too bloody hot to do logging right now and my wood pile is already bloated, so this phase of the project will wait for winter. By then, I should have plenty of “before” data to compare to the “after” data. Stay tuned.

–Neal

What’s with these $7 Solar Panels?

• Posted By : Neal Collier
• Technical Blog
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Have you seen the $7 solar modules on the Sun Electronics web site? They are 70 watts, so that’s only a dime apiece for a whole watt! Can they be any good???

I admit it, I am a tightwad and bargain hunter. I didn’t need 50 more solar modules, but I saw where John was advertising these solar panels so cheap and I could not resist. Apparently a lot of people have reservations about these things, because he still has plenty. I’ll tell you the good, bad and ugly bits of my experience and you can make up your own mind if they are for you.

First of all, these are first rate, name brand gear. Google First Solar FS-270 for the spec sheets. Second, they are second hand, having been removed from a school. (why were they removed????) Finally, they are “thin film” modules.

Mostly John sells poly- or mono-crystalline modules. There is somehow a perception among some folks that these are better. However, if you look at pictures of solar farms, you will see an awful lot of these very same thin film modules in use. The pros use them. Here are some general characteristics.

Thin film panels are bigger for a given wattage. Maybe these were taken out of service so they could get more watts from the same amount of space.

Thin film panels work better in cloudy weather. They respond better to the light that is filtered through clouds than the other panels do.

These are rated for 70 watts and have an output of up to 100 volts.

Thin film panels are not as bothered by leaves and bird droppings. In a water monitoring device I used to build, a leaf or a bird splat could cover much of an individual cell on the small panels we used, killing the panel. On the thin film panels, only the amount of area covered by debris was degraded.

Thin film panels are heavier, per watt. The active material is sandwiched between 2 thick sheets of glass.

They are about 2’x4′ in size, making them easy for one person to handle.

Thin film panels can be fragile if not handled properly. Well, I guess that goes for most solar modules, doesn’t it? These have no protective aluminum frame, so there are extra handling and mounting considerations.

Not all of these panels have both MC3 connectors on them. Replacements are cheap, though.

Ok, that’s a bunch of general info. I will now get into a little more detail. I ordered a pallet of 50. That’s the minimum, but you can buy a shipping container full of them, if you need more. That was the easy part. 50 x $7 is $350. Did you ever think you could get 50 modules for that? Just call Roberto or Tony and they can take the order.

Shipping is where it hurts. If you are in California it is not so bad, but to get them all the way to Florida or anywhere else on the East Coast, it will probably cost more than the panels. For some reason, crossing the Mississippi River costs extra, or it seems that way. I did not have a good experience with this part of it. SAIA was the carrier and they have an unmanned terminal in Pensacola. I showed up and nobody was home. The way that works, you show up and wait until about sundown when the drivers start returning and you pounce on the first guy who shows up to demand your load. If you live in a bigger town you’ll probably have a better experience.

Well, a driver came, I pounced and he went off to a storage trailer with his forklift and returned with my pallet. It was leaning, which I took to be a bad sign. A guy in California builds these pallets and then the truckers attempt to break them. This time the trucker won and I got, if I remember right, 13 busted panels in the lot. Sun Electronics refunded the price of the busted units, but I no longer had 50 panels. I had my heart set on 50! Well, that’s how it sometimes goes. I checked and it seems my experience is the exception to the rule.

Well, here they are. What can I do with them? First of all, I need a quick and dirty solar lighting system for my boxcar. It is really a 40′ shipping container, but it looks like a boxcar, so that’s what we call it. It is also a long black hole. I strung LED light strips from stem to stern, plugged them into a cheapo car inverter, connected that to my hot spare 200amp sealed 12v battery, which is regulated by a 40 MPPT controller from my junk box and that is wired to 4 of these panels in parallel. Remember, these things put out about 100v, so you don’t want to get carried away with series strings unless you are doing a high voltage grid tie system and you will need an MPPT controller for battery systems.

I have the greatest of intentions for mounting these panels properly after I put a seal coat on the top of the boxcar. Right now they are just up there on the roof. To complicate solar production they are not only horizontal, but they are in a deep forest where there is rarely a bit of direct sunlight and leaves are constantly falling. Sounds like a challenge, eh? That’s exactly why I chose the thin film panels for this project, because they work well in diffuse light and don’t mind a few leaves. How well are they producing? There is no way of knowing and it is hardly fair to judge them in a case like this. All I can tell you is that whenever I need the lights, they work.

I did another setup at the Solar Shed that is not only pretty conventional, but I have a recorder on it and am getting some data that I can compare with the other arrays.

I put a dozen of them on the wooden test racks below the eaves of the Solar Shed. 12 x 70 will ideally yield 840 watts. The angle is way too steep for summertime, but I can compare with some poly panels mounted on the same rack. If you are into that sine and cosine stuff, we should expect around 70% of rated power this time of year.

The first bit of advice I am going to give you on mounting is don’t mount them on a wooden rack. Wood does not seem to die until you burn it. When it is dry it will twist this way and when it is wet it will twist the other way. My clamps were a little too snug on a couple of the modules and I ended up with two more broken ones. BUT, they still work, so I left them in place, for now.

Again, there is no metal frame, so you use clamps. I used rubber-backed discs, but the original setup used flat bars that you could probably duplicate with aluminum bar stock from Home Depot. A backing of inner tube rubber would be a nice touch. It really is pretty simple. You cannot mount them on a flat surface because the junction box is on the back of the panel. Mine are on wooden rails, but I recommend you go with more stable metal rails to avoid breaking them.

Since a MPPT charge controller typically maxes out around 150v, I just wired all 12 in parallel, using a special combiner harness I built. I can plug or deplug any of the MC3 connectors if I need to troubleshoot. I have plenty of controller capacity left, but I wired up this dozen independently so I can check performance. If I decide to make a permanent thing of this, I will run the power from this array through a combiner that includes diodes so the slight voltage mismatch won’t cause trouble. We don’t want the polys and the thin films fighting.

So how are they doing? I realized early on that I was probably missing a few watts because the system would charge up and the controller would cut back. It is pretty much running all out, now, by adjusting bulking and floating points just a tad higher than the other 5 charge controllers.

So far, they have produced 57 kwh and have averaged a bit over 2 kwh per day in this rainy season with a bit of Sahara dust cloud mixed in. I have seen 3 kwh in a day. I have observed a peak power of 572 of 840 rated watts. Given the steep mounting angle, that is just about right for the panels running at full rated power! John was worried that they might have lost a lot of capacity, but they are great!

Here are some random comparisons with a 1000 watt set on the same rack.

170/840 vs. 161/100 under overcast conditions.

439/840 vs. 400/1000 hazy

69/840 vs. 71/1000 very late and cloudy

345/840 vs. 320/1000 at 1pm under hazy sun

As you can see, the thin films sometimes outperform the larger poly array! I am betting the poly will do much better on the cool, clear days of winter.

I will continue monitor these panels for a performance update.

Conclusions? You’ll need to treat these a little more gently than framed panels, they’ll take up a little more space and they’ll cost a little more to ship, but with their handy size they are great for a DIY’er. You should be able to put together a first rate solar power system at a rock bottom price.

–Neal

Scoundrels and Scalawags

• Posted By : Neal Collier
• Technical Blog
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There are good deals. There are bad deals. There are scoundrels who will try to tell you their bad deal is good. If you don't want to deal with all the razzle dazzle in solar power systems, do it yourself and you will know exactly what you have.

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Look to the West

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The rule is that solar panels have to face the south. Some of us break the rules.

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What Do Cemeteries and Solar Arrays Have in Common?

• Posted By : Neal Collier
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A Cultural Resources Management (CRM) firm recently had a question about an old water-powered mill in our county. You don’t think much about water power in a state as flat as Florida, be we had lots of them. US 29, through Escambia County, could have been named “Industrial Boulevard” there were so many. The firm contacted the University and the query was forwarded until it got to me. I worked on the mill survey a couple of decades ago and am a go-to guy on mills and local history. That query led me to look into the history of the family that owned it. I discovered on a genealogy site that they had a cemetery and nobody knew where it was.

That struck me as a challenge, to find the cemetery. It was an exercise in armchair archaeology, followed by a trip to the field…a fun activity during lockdown, as I’d only be around dead people. I found dead people, thanks to Lidar topgraphy mapping.

There were depressions in the ground, indicating 3 graves. Genealogical reports indicated there should be 3 graves, dating from 1825 through 1849. The family had come here in 1819, when Pensacola was still a Spanish colony and they were prosperous planters.

The graves had been marked with wooden markers. I found bits of pine knots, but nothing that would indicate who was in which grave and I was curious about that. Could I properly determine, by non-invasive means, which person was where?

Mary Ann, the matriarch died first. Then her grandson John. Then John’s mom, Lucretia. I have dates of death for each and when I return I should be able to determine who is where!

How, you ask? By the angle of the sun. Everybody knows the sun rises over there and sets over yonder, corresponding to some variation of east and west. Once you get a solar array, you start noticing a little more. For example, right now, in June, the first and last rays of the day are on the BACK of the Solar Shed! A fat lot of good that does. The sun isn’t moving in a straight line. It travels in an arc. In winter, that arc swings further to the south, beginning and ending closer to actual east and west. The nature of this arc will vary according to where you are.

Now back to cemeteries, most cultures will plant you in an east-west orientation. Modern cemeteries have very precise placement of graves, making things very compact and tidy. In the older cemeteries, sometimes charted using ground-penetrating radar, you’ll see some variation, with the direction of the feet swung a little to the north or south. That is because burials were aligned with the sun and not a compass. Therefore, I should be able to get the angle of the sunrise on a given date and match it to a particular grave. I think it is a pretty sure bet that Little John is between Mom and Grandma, so the real question will be who is on which end. I can’t wait to get back out there and take my measurements.

There are websites and apps that can calculate and display the sun’s arc for any particular time of the year, in case you would find such info handy.

But back to solar power, alignment of the solar panels can make a big difference in your power production and your best angles might be determined by how you use your power. Mine are pointed southward at roughly the same as my latitude, a general recommendation and they perform very well in the winter when the sun is lower and more southerly. I don’t use as much power in the winter because I have a wood furnace and do not use the heat pump. I could use the heat pump to save wood, but I have more wood than I can possibly use.

In the warmer months, the sun is not straight into the panels at noon and it spends a couple of hours shining on the back of the shed. I would be better off with the panels just flat, like on my boat.

Expansion plans for the Solar shed include another 32 feet off to the west, using active panels/shingles, and a carport on the backside for golf cars and lawn mowers, using dead shingles. Now I am rethinking this. Maybe put the dead shingles on the south roof, because I have plenty of winter power, and live shingles on the north carport roof to capture the early and late rays. Maybe the guy whose house is featured in John’s Blog had the right idea.

Yeah, I like that idea, but what is immediately obvious is that solar modules are the wrong shape. They need to be in a keystone shape to maximize the panel area on the roof!

Of course, if you are ground mounted, you can use a tracker. These are available in single and dual axis form. They can be very expensive to buy and install, which raises the question: tracker or more panels? The big boys, who do enough of this stuff to know go both ways. It may just come down to available space. Most of the commercial farms that I have seen with trackers use a single-axis system. That just swings the array from east to west and should make a very big difference.

My own array makes plenty of power, but not necessarily when I need it. I could get by with a smaller pile of batteries, I suspect, if I could put more of that hot afternoon sun directly into my air conditioner instead of on the back of the shed!

This fall, I will be helping my friend Courtney with a new tracking array installation in North Carolina. Stay tuned for a report on the installation and the performance.

Now about that family that misplaced their cemetery, the bulk of them moved to Mississippi in 1836 after planting had depleted the soil here. John Sr. followed later, after Lucretia died. After depleting the soil at their Mississippi plantation, they moved to Texas and guess what? They forgot where they left the Mississippi cemetery, too! They are on their own finding that one.

–Neal

Thar She Blows!

• Posted By : Neal Collier
• Technical Blog
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Fuses offer cheap circuit protection, but there are some precautions you may need to take.

The H-Bridge locked up on my inverter recently. It blew a fuse. It blew it with a lot of self assurance, too. There was no dilly-dallying. Never mind what an H-Bridge is, but in this case it can handle 1200 amps, so when it locks up, something bad could happen. That’s why there’s a fuse.

Usually, you kind of work your way up to blowing a fuse. The load exceeds the rating, the metal melts and everything stops. When you get over 1200 amps trying to get through a 150 amp fuse, you get a plasma bomb. The blast made a perfectly round hole in the mica window that is there to contain the failure and then it blew the plastic no-finger-pokey cover across the room.

The wife says there was lightning and then stuff didn’t work. So, you think maybe it blew a fuse and you go to replace it because you don’t know you have a locked-up H-bridge. You are careful because all of those capacitors in the inverter make a good pop anytime you put in the fuse. What happens, though, is not a good pop. You get a major arc that burns away part of the fuse holder and part of the fuse. Then the link BLOWS with great vigor, leaving you with black fingers. Being the cautious type, the fingers were on the protective casing of the fuse instead of over the window where the blast originates. The moral of the story is to be careful installing a new fuse.

There are different kinds of fuses for different purposes. Used to be only “T” fuses were used with inverters. I have used them when that is what I had, but they are very expensive. One thing I am pretty sure of, they would be hard to explode. Many cartridge fuses are filled with sand to contain and dissipate any excess energy they might encounter. I like ANL fuses. They are effective and dirt cheap. They are popular on boats and that is my upcoming primary wiring projects as I build the two Solar Yachts. They are not that good at containing plasma balls.

A disadvantage of cartridge fuses is that some holders can lose their spring tension and the connection can get a bit resistive, risking fire. For that very reason we had he circuit panel replaced at Mom’s house about 20 years ago. It was getting hot and smoky! Both the T and the ANL fuses are firmly bolted into place.

Whichever you choose, take care when inserting a fuse, especially when power is present. Remove the power when possible. In this case, there is going to be a pop somewhere. I would rather it be at a fuse holder than at the big plastic box full of explosive hydrogen (the battery).–Neal

Zero Export Grid Tie

• Posted By : Neal Collier
• Technical Blog
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They keep changing the rules on grid tie. Avoid dual meters, special fees and changing deals by mixing your power with that from the power company, without backfeeding to the grid.

Many years ago, a fellow came up with a gadget he called a synchronous inverter. Today we call it a grid tie inverter, and it changed everything. It allowed you to mix sun power DC current with the utility AC current. If you were using a heavy load, the solar power would replace some or all of it. If you were not using much of a load it would flow out through the meter, spinning it backwards to reduce the power bill. As long as you used a little more from the grid than you made with the solar, things were ok. This was called guerilla solar.

If the power company came by to read your meter and got a negative number because you made more power than you used, well that is when the trouble started. Some power companies forbid you to do grid-tie, some encourage it, some pay you to do it, some make you pay dearly and they’ll pretty much all require some special equipment. Your mileage may vary. Check with your local power company before you start.

My friend Courtney got lucky with his system. He lived in South Carolina where they actually paid him to add solar, plus he got Federal tax credits, so the whole thing came out pretty much free. There was a price to be paid in paperwork and jumping through hoops. He and I did the work, but he had to have a licensed electrical contractor and a NABCEP solar installer inspect the work before it could be commissioned. He also had to have a mechanical engineer sign off on his pergola being strong enough to hold the panels. It was strong enough for all the panels and the two old guys putting them up there, but it had to have the engineer’s stamp of approval. There was lots of paperwork.

On the other hand, there’s my power co-op that throws up every obstacle to grid-tie. I know of three people who have done it, but I can’t see where they are saving much. Others have had their power companies welcome grid-tie, only to change the rules later and jack up the fees.

Being the rebel I am, I have spent about a year studying how to use your solar power and not get the power company involved. One lovely way of doing this, used by Tom, is to use a grid interactive inverter. These can usually do grid-tie, but can also provide standalone power for use if the grid is down. During the day, Tom’s array charges his batteries and they feed the DC to the inverter that makes the AC. The inverter also has an input from the grid. As long as the batteries have plenty of power, the house runs on solar. Tom uses loads of power. Computers, TV, lights and coffee pot are always on. The inverter lets him select just how much he will draw from the batteries. He sets a fairly shallow draw to give the batteries longer life.

To accomplish this, Tom has a “generator plug” and a transfer switch. There is an actual diesel generating setup, but for everyday purposes, his solar system is the generator. So, a grid line goes to the inverter and the inverter runs the house. At night, the A/C will drag the batteries down pretty quickly and the unit automatically switches to grid power. If a hurricane takes out the grid and blows away the solar array, he can fire up the generator and charge the batteries with it or run directly into the house.

Tom’s stuff is not grid-tie, though. Courtney brought over a pallet of LG 300 panels and a case of Enphase microinverters and challenged me to see what I could come up with for operating an air conditioner from solar. No problem, except that I can’t do grid tie.

I played with the microinverters on my off grid system, which goes to my “generator plug” to see how far I could push it without a visit from the big white truck. I figured a plan and calculated how much my A/C compressor used and selected enough panels and micro inverters to match. The output of the microinverters went underground to the MOTOR SIDE of the big contactor under the hood of the A/C. When the A/C comes on, the microinverters are energized and they connect sunlight power to the cooler. Success!

Limited success, I should say. By Federal law, the microinverter has to wait 5 minutes before it does its thing. If you have a short cycling A/C, then that is a problem. Most HVAC contractors oversize their gear, but in my case I have a system for upstairs and a system for downstairs. The smaller upstairs unit is only 1.5 tons, but it keeps the house comfortable downstairs, if a bit chilly upstairs, while running nearly constantly on a really hot day. In this configuration it really saved a lot on my power bill and I had the house a lot more comfortable than if I were buying power. Best of all, I did not have to deal with the power company.

So here are the limitations. We are only saving power on the A/C, we are saving nothing at night and very little on cloudy days. Can we improve on that? Why, yes we can! It turns out these particular Enphase inverters have a form of limiting in them. Though they are being fed with 300 watt panels, they can only feed a bit over 200 watts into the power line. That isn’t as kookie as it sounds. It sort of levels things out when the clouds pass. It also means you can connect batteries to the microinverters and use the panels to charge the batteries through charge controllers. These micros are designed to operate from 60 cell panels, so a 24 volt battery bank works fine as a feed. Now the microinverters can microinvert at night or when cloudy, within limits of course. We saved even more on A/C.

Can we do better? Is there a way to feed the power to the whole house without spilling any out the meter? Yup!

So I ripped out all the microinverters and started over. First, the panels were arranged in series pairs and the DC was sent underground to the “dog house” next to the A/C units. In the dog house, two Grid Tie Interfaces, Limiter (GTIL), sometimes known as Zero Export Grid Tie, were installed, each plugged into a 110 plug from each leg of the 220 line. Some of you may be thinking, “Hey I’ve seen those blue boxes and they make one for 220. Why not use that one?” There’s 220, Euro style and there’s 220 American split phase. The bigger blue box does not understand the American Way.

Anyway, you plug these GTIL boxes into 110 outlets, add solar and, voila, grid tie. But not limited. You’ll get the visit from the big white truck and probably quickly if you have a smart meter. It’ll call home and you are busted! However, there are sensing coils that go in the big gray breaker box. They can sense if the power is coming or going. With the sensor coils in place, turned the right direction and plugged into the right box, the solar power will come rushing into the house wiring, filling every light bulb and small appliance, but when it tries to squeeze out toward the meter, the sensors stop it in its tracks, leaving maybe 4 watts coming from each leg of the utility.

In my case, the boxes are called “1000” units, but actually rated at 950 watts each. That may be a bit of an exaggeration. Still, under ideal conditions, they will handle most of the background load, but get overwhelmed a bit when the clothes dryer or oven are used. The dryer, for example uses 5000 watts, normally, but if the GTIL pair can knock 1500 watts off that, then that adds up to some savings.

Let me interrupt for a moment, in case you are thinking of getting some of these wondrous boxes. If you already have a grid-tie system, it is quite possible that adding a simple gizmo will allow you to do the same tricks with your existing gear.

Back to the GTILs I use, am I perfectly happy? No. For a couple of reasons, or more. First of all, the two inverters are connected to the same solar array. Solar panels are a somewhat high impedance source of power, which is to say that when you put a load on them, the voltage goes down. If one of the boxes is providing 800 watts to the coffee maker and someone starts up something substantial on the other leg, the solar source voltage drags down a bit further causing the first unit to trip out while the second tries to take charge. Before you know it a full-on fight ensues and nobody is contributing power. Sometimes both inverters will settle down in harmony and then a puffy little cloud goes sailing by and everything trips out again. Can this be fixed? Yes, to some degree, by simply dividing the array into two separate branches. The thing is, the solar panels are 200 feet from the point of use and digging trenches and pulling expensive cable is a bother. No, it isn’t quite as dire as that, in truth. I do have several cables in parallel that could be separated, but I have bigger plans, so no use getting involved in wrestling with heavy gage wires.

The next phase of the plan is to add batteries. Again, we will have power available around the clock, as we did with the microinverters. Batteries are a low impedance power source, so the two GTIL units should not fight.

The next step took some time to complete because I needed batteries. I looked far and wide for just the right batteries for my Solar Yacht project with the idea of running the house on them as a test and putting the old batteries, Sun 230s from Sun Electronics, on the GTIL project. Batteries, cash and opportunity converged and I had batteries.

The lines from the solar panels, LG 300s, operated in parallel pairs, for a total of 2400 watts, were disconnected from the GTIL units and reconnected to a 60 amp MPPT charge controller I found in a drawer. The output of that was connected to terminal blocks with connections to the battery and the GTILS. Oh, yeah, there were some fuses, circuit breakers and a surge protector thrown inline for safety. It worked.

Then Courtney wanted his panels back, so I put up a kilowatt of panels from a boat project. Less power, but since they were charging the batteries there is usually enough. Now the only limitation is high usage on a cloudy day, but isn’t that always the case?

Now the batteries can run loads any hour of the day or night. Cooking on the stove top? Covered. Electric clothes dryer? Knocks off nearly a third of that. Washing machine? Covered. Baking blackberry cobblers? Uses only about 1 kwh from the grid for a 5000 watt oven. There were two mystery loads that showed up on the monitors. They turned out to be a fridge and a freezer that had been left on the grid. They have been moved over to the all solar system, but they were being covered by the battery GTIL.

There was 72 kwh use from the grid this month, about half of last month. I had projected that it would only be 50 kwh, but in the corona lockdown, my wife deals with the situation by doing laundry. Many more hours of dryer time are being consumed than are actually needed, by my calculation, but my calculations don’t seem to count. I keep quiet about her laundry obsession and she makes me cobbler. I don’t mind losing a kwh to get a bowl of cobbler! The limited grid tie took care of an additional 67 kwh. The grid tie solar would have provided more power, but about the 6^th day I discovered I had an unexpected load of a fridge and a chest freezer that had been overlooked. They were moved to the main solar circuit so they would be left running if the grid went down. They would have used another 72kwh from the grid tie.

OK, so if I have explained this properly, you may be wondering how you can get some of this limiting grid tie stuff, am I right? If you already have a grid-tie power system, you may be able to add the limiting system.

Most GT systems have an optional power monitoring module available that will allow you to keep up with your power use and grid interactions. Some of these have sensing coils available and they have the software to convert to limiting operation. Check your manual. It’ll probably be a very small mention. I know that SMA/Sunny Boy has a power meter accessory that can do this. Elgrispower.com has one they claim works with about a dozen different grid tie inverters.

No, if you are running a 600v string inverter system, you probably don’t even want to think about running batteries. If the power company decided to charge you a lot of money to connect grid tie, you can be rid of that nonsense because the power is being mixed in your house and never going out to join forces with their kilowatts.

If you have net metering or some arrangement that is satisfactory, then never mind. If your power company is trying to discourage solar and jacking up your bill with fees, then this could be for you. It is the rebirth of guerilla solar and may be just the thing to save you some money on your power bill.–Neal