Multiplus Charging Voltage Spike

Hello, I have recently built a system using a 24V 272AH LiFePO4 battery bank, 200A BMS, 24v/3000a Multiplus, connected to a Fused Lynx Distributor (MPPT hasn't arrived yet). I have it all wired and set up, and when the multiplus is on Invert only everything works perfectly, both DC and AC. But when I change it to charge mode, the voltage on the BMS, multiplus reading and the battery bank quickly rises and immedietly goes into absorption mode. I had to turn down the absorption limit so that things don't trip off as the voltage keeps rising while testing. I can't figure out what is causing this, all the connections are good and tight, I've stared at the wiring for hours and everything looks good. Any advice on what to look at next?

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Rob Duthie commented · Mar 22, 2021 at 07:17 PM

It normaly is the battery bank has not balanced yet, after some time ther BMS will balance out the cells then it will settle down. You don't mention the brand of battery bank and the control? etc.

in the CCGX you can change the charge current for new install for DVCC charge currents for Lithium batteries.

Regards

Rob D

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Ryan Eldridge Rob Duthie commented · Mar 22, 2021 at 07:25 PM

It's a DIY w/ Lishen 272AH cells and a Daly 200a BMS. I figured it was expected but didn't know what to do about it since it would ramp up too high and trigger high voltage shutoffs. Didn't think to just change the charge current, thanks will try that.

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Rob Duthie Ryan Eldridge commented · Mar 22, 2021 at 08:28 PM

Hi Ryan

That is why they introduced it into the DVCC settings for this very reason. For most branded batteries eg BYD and Pylontech etc. For DIY not sure about depends on the BMS, and how it is can controlled or not or is compatable with the Venus sofware etc.

And have you setup the muliplus VE configure for lithium battery set points etc?

Regard
Rob D

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