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Growatt won't let me charge batteries to full?

griftin

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Dec 5, 2021
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I have a 24-volt growatt system. Currently it is connected to two 12-volt 200 amp lithium ion batteries in series. I have a shunt hooked up with battery monitor, and the battery monitor shows it at 25.8v. when I'm charging it off of the generator, the growatt shows the batteries at 28.4 which is what I currently have the float and capacity set to on the growatt. As soon as I turn off the generator it drops down to 25.8 or close to it. If I let it run, the inverter will shut off and the batteries will drop down to the lower number, and then kick the inverter back on, jumping up the voltage again to 28.4 which then triggers the inverter to shut off. How can I increase the range of the charge if the inverter always shuts off when it reaches an inaccurate 28.4. I manually checked the batteries and they are still balanced and when I check them in series they match the shunt battery monitor. Should I do a full discharge? I've considered taking the batteries off and draining them, and then just charging them in parallel. I have no idea. I do not have a balancer on the batteries at this moment.

This also happens if I let my solar panels charge it as well. Just in case you were going to say it's something to do with the generator.

If I'm missing any data, please let me know
 

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As soon as I turn off the generator it drops down to 25.8 or close to it.

Well, it shouldn't do that, should it?
Under moderate load, it should drop to 26.8, not 25. 25.8 is roughly 25% SOC.
It looks like you might have a damaged/dying cell :·/
 
It really sounds like a resistance problem. Voltage is higher at the source than the load. You are probably charging at the full 80 amps? Connections connectors wire size. Get it charging and use a DVM. I once found I had a new breaker on some panels that had a 20% voltage drop across it.
 
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