You can build a fully integrated solar power system using matched components or you can mix and match from a variety of manufacturers. Which is the best way to go? What are the advantages and disadvantages?
My solar power system was not designed as presently it is. It just sort of happened and kept happening over 30 years, or so. It continues to happen and it would come under the heading of a hodgepodge. That is not necessarily a bad thing, but it has its limitations.
Every now and then I tear down the control panel and rebuild, but continue to reuse components to save costs. The rebuild keeps it “pretty” and safe. The latest rebuild was more of an annexation, as I put a complete separate system outside and tied the two together. It would have been nice to tear down the system-in-a-box that I bought, but it was such a nice system and worked well. My motto is, “if it ain’t broke, don’t fix it.” I have other mottoes for other occasions, but that one fit here.
Much of the equipment from my old 24v system did not move over because it won’t work on 48v, which I use now. So how is it that I have such diversity of hardware? As the Solar Shed grew from 16 feet to 68 feet, I needed more gear to keep up with capacity. I was also trying to find just the right gear for my Solar Yacht project (which languishes).
Capable hardware that had a weak display and was hard to use. One of those is in the system, but we are in a state of detente. As long as it does not cause any trouble I leave it alone.
There was a model that was compact, capable and had a dazzling display. I knew that was the one until the display started breaking down and turning to static. Two of those are in obscure systems that will never need their settings changed.
There is one model that was pretty good, but the early software versions could throw the batteries into thermal runaway, which is not desirable. The later models are almost perfect, though not marinized to resist a salt environment.
The anchor of my system, I guess, would be a version of the FlexMax family from Outback. This is just plain great, rugged gear, but it is a bit large for the yacht.
Finally, the annex system has a Midnite Solar 250 charge controller. That’s another can’t-go-wrong choice for home. They have a marinized controller, too, or is that Outback? Anyway…
All of these charge controllers control the charge. Well, except for the two with the bad firmware. If you need more functionality, it’ll cost you and it might be worth it. What more do you need? Glad you asked.
You know I mentioned the thermal runaway? The Outback and MidNite units have temperature sensors. That is a really good feature to have if you use agm batteries or have a bit too much solar for the amount of battery you have. You don’t want your batteries to cook and you’ll find that for best performance and longevity, the charging characteristics should change with temperature.
Also, the full featured units often have some sort of networking to allow you to keep up with all the conditions and statistics of your system, some even with a phone app. A lot of people go crazy over data to start and then let it slide after the “new” wears off. However, if you are troubleshooting a change in performance data can be very important. I’m trying to write about some changes and coming by the data is not as easy as calling up a spreadsheet on the laptop. I’m having to manually log numbers in a notebook.
However, while many of my controllers just display current conditions, the Midnite and the FlexMax supply all sorts of data. The Flexmax logs 180 days worth. I am comparing a traditionally South-facing legacy bank of solar modules with the similarly sized annex bank that is facing westward. I will write about that later, but (spoiler alert!) the West bank is kicking out the KWH! I have some add-on meters and am waiting on some more so that I can get more information. My homebrew inverter is equipped with a totalizer, but I have not been able to find one in the pricey SMA Sunny Island inverters of the annex. The only way I can presently tell how much fun I am having is by looking at my power bill. Spoiler alert for another article is that I am having more fun than last year. I’ll let you know the how and why in a different blog piece.
I talked mostly about the charge controllers. Some of the inverters are pretty darn smart, too. My homemade inverter is dumb as a rock (and twice as heavy), but it cranks out the power. The SMA units talk to the charge controller and together they work things out. External boxes can give you more data and features. The downside of all that is that there is a thicker manual to read. If I had a manual for the homemade SunKing inverter it would be limited to telling you the location of the ON-OFF switch. I recently had to delve into the inner workings of the SMA inverter and I have to say I was intimidated. Once I calmed down and read through it I was in on their way of doing business. I made a couple of notes on what I needed to do to change a parameter in the generator’s battery charging specs, it was easy and I left the cheat sheet taped to the inverter for future changes. No big deal. Just read the manual.
So what’s the upshot? You can save money if you can get by with basic, no frills hardware, though there will be more manuals to read. The big name outfits can provide you with more information, more features and a system in which all the components can live in harmony. NOT having to resolve a problem because one hardware maker blames the other hardware maker is great, too. The A-list makers also tend to have good customer service and reasonable repair prices. I have seen one lesser maker charge full value of an inverter just for a control board. If you have a problem with most of the Ebay/China stuff, it’ll cost you more to ship it back than to buy a new one, so those items should be considered disposables.