Solar Power

Chris0nllyn

Well-Known Member
Just an FYI for anyone using a 12VDC to 120VAC inverter. They all have a 3 prong outlet (hot, neutral, ground) but the ground is not connected to a real ground. If you use one in damp conditions where you'd normally use a GFI circuit breaker for protection, a GFI cannot work and there is no GFI protection.

I came across this out of curiosity, used a GFI tester on the 120VAC output, knowing it was going to be used outside in potentially damp/wet conditions. GFI tester showed no ground circuit. Tried 2 other inverters, same thing. There is no "earth" grounding. The inverter frame is "grounded", but only to the negative pole of the battery.
A ground isn't needed for a GFCI to work property. It senses current on the neutral and trips.

That's why old two-prong (ungrounded) outlets must be swapped with GFCI outlets or breakers.
 

Chris0nllyn

Well-Known Member
I have a spare full size fridge, top freezer, just sitting there. I got curious if the solar system could power it, so I hooked up the watt meter. Again, surprised. Initial turn-on surge was about 1500 watts, but quickly fell to 120 watts. In partial sun, the solar system can easily cover 120 watts. After it ran for a few hours, it fell to 95 watts. Barely more than the freezer/fridge I put together. But being bigger, it will run much much longer. During the day, not a problem, but it would need a much bigger battery than the 45Ah I have now to carry it thru the night.

So, in a pinch, the little, portable solar system could run a full size fridge. Interesting.
I came across this thing recently.

Dometic powered cooler with a fridge side, freezer side, and optional deep freeze. The biggest model only uses 0.85Ah/hr @ 12VDC (or 10.2Wh).
Looks neat, but probably more expensive than your whole set up (it's about $1,200).
https://www.dometic.com/en-us/us/products/food-and-beverage/coolers/electric-coolers/dometic-cfx-65w-_-152179#specifications
 
I've looked at many of the 12v fridges, and they are all very expensive for what you get, which is why I thought it was a great thing to build the one I did. Cheap, and works better.

Regarding the GFI, ok, I've been educated. Did a little research on GFIs and you're right, it senses a mis-match between hot and neutral output vs input, not ground. It's called "ground fault" not because the ground has faulted, but because the hot has most likely found a path to ground. Given that, I'm going to add a GFI breaker to my setup and re-test. I'd feel a lot better with an operational GFI when outside.
 
Well, contrary to the manufacturer of the inverter, a GFI breaker between their inverter and my 120VAC hardware works correctly, as intended.

Have to modify the case a bit to accommodate the GFI as it's bigger than the duplex outlet I have in there now.

Thanx for the heads up, Chris.
 
Replaced the outlet with a GFI, mounted up the solar charger display and remote on/off switch for the inverter.

Other than building a stand for the solar panel, this is pretty much a done deal.
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