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Daly BMS, cell voltage drift / charge port shutoff defective?

Lorenzo90

New Member
Joined
Nov 27, 2020
Messages
47
Hi,
I just finished installing my off-grid system for my camper.
I have some questions regarding cell balancing and a problem I have with the BMS.
It's a 24v lifepo4 8s battery,
Daly BMS 250ah
Victron shunt
Epever all-in-one inverter
1200w of solar panels
Stirling dc-dc charger. (Alternator)

I top balanced the batteries more than a year go, than they got discharged few 6 months ago, and stayed discharged until last week when I finally finished my system.

I've been now charging up the battery with the dc-dc inverter (750w/~30a) and I noticed quit e a voltage drift on one of the cells of 0.22v while charging (check photo)

How much should I be worried about it? The votage drift seems to get higher the more I charge the battery, so when the cell reached 3.7, I stopped charging..
Afterwards when the cell were resting I had a difference of 0.02v.

How much of a voltage drift should I tolerate? How can I mitigate the problem, and should I do something about that cell that is high?


2 problem..
When I switched off charging i've done it from the the app, switching off the charging port.

But the voltage did not dropped below 27v, and I could see few amps coming on the smart shunt.

The dc-dc charger stopped charging, as it should happen...

But the mppt (in the all in one unit) was still able to pump in few amps and it was keeping the battery at a high voltage of ~27.5v.

How was this possible? Once I disconnect the solar panels the current stopped.


How is it possible that the mppt was able to keep the voltage high and pushing 3-4 amp through even if the charging port was shut down?

That worries me on the capacity of the BMS of actually protect the battery..
 
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