Overkill BMS and Battery Data

[guidecca]

I have two 8s 100A Overkill BMS's on (16) 3.2v 100aH LiFePO4 cells in a 24v battery banks. The inverter is off, there is no load on the batteries, the remote monitoring display MT50 shows the batteries charging (see attached). The MT50 shows a charged battery. The software shows zero amp hours capacity of 100aH. And, the batteries are discharging. I do not understand it and hope someone does. Thanks.

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[sunshine_eggo]

I have two 8s 100A Overkill BMS's on (16) 3.2v 100aH LiFePO4 cells in a 24v battery banks. The inverter is off, there is no load on the batteries, the remote monitoring display MT50 shows the batteries charging (see attached). The MT50 shows a charged battery.

No it doesn't. It's voltage based and worthless.

The software shows zero amp hours capacity of 100aH. And, the batteries are discharging. I do not understand it and hope someone does. Thanks.

They're in parallel, so they can pass current back and forth.

Check all connections for accuracy and quality.

Evaluate performance of each battery individually.

check that each battery shows 0A when disconnected from everything.

 

[guidecca]

Sounds like a big job. Wonder if the bluetooth connected software is accurate. I will try the USB connected module and its software and see if there is any change and go from there. This USB device: https://overkillsolar.com/product/usb-module-for-bms/.

 

[sunshine_eggo]

Cool. Love it when best-practice fundamental troubleshooting is "a big job" and too much for someone to deal with, so they ignore advice and go off on some tangent.

Good luck!

 

[guidecca]

Those are your words, not mine. Try the easy "some tangent" first and before disconnecting the battery and "dealing with it," is all I'm saying.
Here is what I'm talking about. The attachments are from the USB modules, one for each 8s BMS, and this software shows 71% battery capacity. Not sure why the cells are not populating with voltage data. Also, are the basic configuration numbers in the ball park? Anyone familiar with Overkill software?

 

[guidecca]

In the screenshot above the batteries show zero amp hours and discharging. Today the batteries show 97% and 98% amp hours at about 27.95v and discharging. I turned off solar panel input at a breaker to the solar charge controller and the discharging stopped. Wonder if the BMS is discharging the batteries or if there is some small load doing it?