Reverend David’s Solar Freezer

Using the hot sun to keep the groceries cold. Awesome!

I met Reverend David a while back and run into him every now and then. He and I, turns out, have similar backgrounds. Our electronics backgrounds started in Pensacola radio stations. He was engineer at WMEZ and I was engineer at WCOA, but offset by a few years, so we didn’t meet until 40 years later. Radio operators are sometimes known as “sparks” so I guess it is only natural that me being retired and him preaching, we both still have an urge to make some sparks.

We figured out we both have an interest in solar and we talk about that. I knew he wanted a starter system of some sort, but we never got too much into details. He was kicking himself after he bought panels someplace else and I told him what they cost at Sun Electronics. I recently saw him at a bake sale and he revealed his now running system.

He has 3 solar modules, around a kilowatt. They feed a 12volt battery, size unknown to me (I think GC2), through a FlexMax 80. My first impression is wow that’s a huge charge controller for only a kw, but then I remember this is a 12 volt system. 80 amps x 12 volts is 960 watts. The Flex Max limits the power to what won’t hurt it and the Rev will still get his kw as the voltage rises a bit. If this were a 24 volt system he could go for 2kw or nearly 4kw on 48volts.

But he went with 12 volts because he had a 12volt Tripp-Light inverter, around 1500 watts, if I recall correctly. I have come across several of those and they seem to be rugged and reliable. They are of the “modified sinewave” variety, actually a modified square wave. He was surprised that his freezer, which runs at only a few hundred watt, would not run on a smaller inverter. I reminded him, as I remind you now, refrigeration equipment can have some really nasty startup requirements. I had to modify my 2000 watt air conditioners to start with a 5500watt inverter. Moreover, motors really prefer a genuine sine wave.

All the same, David’s freezer is getting along just fine on his system. If he has 3 or 4 days of gloomy weather he has to change over to grid power. A bigger battery would fix that. There’s never enough battery!

So aside from being a plaything for an old broadcast engineer, what good is it? Well, let’s say we had a hurricane and the power is off. The weather is always GREAT after a hurricane. It could do its thing saving the freezer food, but could provide ice to save the fridge food until consumed. It could make a pot of coffee in the morning and it could run the microwave a little. Yessir, that tiny solar system could come in handy after a storm.

Moreover, it is small enough that the panels could probably be brought indoors until after the storm is gone to ensure their survival.

A little system like Reverend David’s could be a great starter project for you and be a lifesaver in an emergency, if you are looking to get into solar power.


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