There’s An App for That

In early summer of 2015, I was on my solar expedition launch Sun King. Cruising up the Tennesee-Tombigbee Waterway. It was raining and getting dark as I approached the lock and dam at Aberdeen, Mississippi. I don’t like to run in the rain and there are limitations to running in the dark in a solar-powered boat. Nonetheless, I pressed on. I had a rendezvous the next day. An important one. My wife and Mom were bringing supplies to restock my chips and jerky rations.

Getting through the lock was no big deal, but it was raining pretty well by the time I cleared. I turned to starboard and went looking for the channel markers to the Aberdeen marina. It turns out the LED floodlight was inadequate and the rain made it impossible to find the way. It is tricky in good weather if you are a stranger. I found a shallow spot and dropped anchor for the night. After supper, I heard a power boat go by. Local river rats always know the way.

It was a good thing I locked through when I did. By morning, the river was up 20 feet and the current was faster than my boat. Man, it had really rained. It was still gloomy, but after breakfast and coffee I wound my way through the channel and found the marina. It was still a little wet, so I tied up at the seawall to wait before checking in with the folks who ran the place. Note that despite running in the dark, fixing supper, fixing breakfast and getting underway in the gloom of a rainy morning, I still had plenty of power.

Tech specs: 1620 watts of solar panels, 6x Energizer 8v golf car batteries, arranged series-parallel for 350 ah at 24vdc. 8 kw inverter (overkill, but the 3kw I had before had died). Motor was a custom build, based on an array of Minn-Kota parts.

After 4 days of cloudy weather, the batteries may be getting low in your solar power system. Try cutting back on the loads as the panels will charge, even on a cloudy day. This day, I fixed a cup of coffee and went beach combing along an island shore in Tennessee Lake.

It would be a while before the resupply crew would arrive, so I reclined my captain’s chair and settled back for a little snooze. It had been an unsettling night with all the thunder and lightning going on. My nap didn’t last long as suddenly the gawdawfulest blast of catterwallin’ occurred and just kept on.

Mississippi has a network of storm sirens throughout the land. You can hear them for miles and if you are between them they set up something of an echo. I had tied up right under one of these infernal devices. What a rude awakening!

I survived that day at Aberdeen and the various perils of the entire 1920 miles of the trip around the big island of Mississippi. Bet you didn’t know Mississippi was an island did you? If you can drive a boat around it it is and I did so. So it must be an island.

Yesterday morning I had a jarring awakening. My phone has somehow developed the ability to be the equivalent of a Mississippi tornado siren. It doesn’t matter what the volume settings are on the phone, this makes itself heard. Yup, tornadoes inbound. I checked the radar and saw it was doing the usual split up the river that is our county line and the other river that is our state line. I don’t know why, but the tornadoes like the river valleys better than our ridge. I’m ok with that and I rolled over to catch some more zzzzs, while Pensacola got thrashed.

Later I got to thinking about phone apps that might be useful for solar. Since I have gone fully off grid, the days of endless gloom and rain have begun. I have been going through some neglected areas of my system to try to squeeze out a few more watts.

At the planning stage, I found Suncalc which shows the sun angles at different times of day and in different seasons. If you can’t site your solar panels to the traditional south orientation, Suncalc might help you find a good alternative.

At the building phase, there is a app that lets you use your phone as a level or clinometer. Note that not all phones have a sensor array. I hold on to old Androids to use as tools if they have sensors my regular phone does not. If you can play video games by tilting the phone, you have the sensors that will let you mount your supports vertical and horizontal and then set the panel angles.

Some phones have a magnetic sensor that will drive a compass app to select your direction of the array. If you don’t have that, some compass programs will work with the GPS in your phone if you walk around a little.

There are also a number of apps to predict your solar insolation or available sun power. Some are purely theoretical and some are somewhat interactive. Solar Radiation Calculator decided that at my location I should receive 2920 kwh per year, per square meter, from the sun. Given that panels in perfect alignment are good for around 20% efficiency, I need a number of square meters. That one is probably best for the planning phase. Another app i tried, PV Solar Forecast, scans weather service radar and cloud maps to guess how many watts your system will give you. I am still learning this, but it looks like it is assuming you have a grid tie system. There are some calibrations available, so this one might be useful for rough estimates of the day’s performance.

Not a lot of watts, today. We should catch up over the weekend.

Now, for even more accurate info, you will find there are apps that will talk to your charge controllers, inverters or grid tie system to get the direct scoop on things. There are even aftermarket wattmeters that your phone can monitor with Bluetooth.

Try roaming the Apple and Play stores for apps. Usually, there are free ones you can try. These often come with reduced features and annoying ads. If you find an app you really like, paying a very few dollars can make those ads go away and bring you some new features.

Let’s see now, earlier, the app said I was making 400 watts. says I have perked up to 1.6 kw, and by the end of the day as the rain clears I’ll still have clouds and low output. Not a good solar day, but I already sort of knew that. Looks like tomorrow will be better. Good, my batteries need those kilowatts.

—Neal