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diy solar

Upgraded the batteries on my solar generator

Electrobob

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Joined
Jul 25, 2021
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Arizona
I wanted longer run time from my solar generator so I swapped out the four 12v 100 ah batteries for two 24v 200ah batteries which doubled the capacity. According to the Ampere Time website and literature that came with the batteries these are 5120 watt hour batteries, but the math says 4800 so not sure how they get that number, but going by their specs this is now a 10kw system.

The Ampere Time batteries came with about a 30% charge so it took a good while to charge them separately. I then put them in parallel and left them for a couple days. I had to take the side rails off the cart as these batteries are wider. I think I will get some 2 inch ratchet straps to secure them down better. I can run a 6K BTU window unit air conditioner, refrigerator, light, small tv and charge tablets and phones without having to worry. I have four 250 watt panels which isn’t quite enough for the size of batteries now but I will just have to wait to do anything about that. I really recommend making these if anyone is wondering or on the fence about it. I say definitely go ahead with it.

As an interesting side note, I was talking with a tech at Signature Solar a little while ago and he was telling me about a call he got from someone who had made one of these DIY solar generators using a hand truck and somehow the whole thing went live, and he was recommending against building them. My cart has inflatable rubber tires and a rubber mat under the batteries, and the upper part is peg board supported by PVC pipe which is all non conductive material and has no contact with the batteries. The pull handle is covered with neoprene, then wrapped with electrical tape and then hockey tape over that for grip, so I am satisfied with the isolation. This is basically the 3rd generation of this thing and I am definitely done now. I know I said that last time but this time I really mean it, otherwise I may need to seek rehab for solar addiction. On the other hand, I now have four 12v 100ah batteries not doing anything and with just a little more money I could…....wait...please stop me!

May your skies be always sunny. :)
 

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According to the Ampere Time website and literature that came with the batteries these are 5120 watt hour batteries, but the math says 4800 so not sure how they get that number, but going by their specs this is now a 10kw system.
The actual average voltage of a lifepo4 24 battery is actually 25.6 volts x 200 ah equaling 5120 watt hours
 
As an interesting side note, I was talking with a tech at Signature Solar a little while ago and he was telling me about a call he got from someone who had made one of these DIY solar generators using a hand truck and somehow the whole thing went live, and he was recommending against building them.
I'm not sure how someone doing a poor quality build, aka unsafe build, categorically makes it a bad idea.

If it works for you and your needs, carry on! Learn, study, be safe, and keep everything isolated and grounded as appropriate.
 
I swapped out the four 12v 100 ah batteries for two 24v 200ah batteries which doubled the capacity. According to the Ampere Time website and literature that came with the batteries these are 5120 watt hour batteries, but the math says 4800 so not sure how they get that number, but going by their specs this is now a 10kw system.
Not getting the calculations here :unsure:
 
Not getting the calculations here :unsure:
24v batteries are actually 25.6V batteries. At 200 amps hours each, that's 25.6 * 200 = 5,120 watt hours, or 5.12 kilowatt hours (kWh).

5.12 kWh times two batteries equals 10.24 kWh system capacity (but missing the "h" on "this is now a 10kWh system").
 
In battery mode the Growatt I had had a neutral to ground bond on the ac output. When mounted to a metal cart that would become a neutral to cart bond. On rubber wheels if you're touching the cart and your feet or other part of you are touching an earth ground then funny things can happen ?
Additionally when in grid assist mode both the ac input and ac output had continuity between both neutrals and both grounds on my growatt.
All things to consider when building a cart.
 
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