locked Re: Batteries starting to get weak - MMM - What to do -

Scott SV Tengah

Oliver, that has not been my experience. Perhaps Victron makes bad internal cell-cell connections but I surmise it might have to do with my keeping the Amel configuration of 12v batteries paired up in serial to create 24v and paralleled to create the total AH. This is useful in case your starter battery dies and you need to borrow a 12v battery to start engine/genset. I opted to retain that redundancy.

To my knowledge, BMS systems do not typically balance between serial pairs of batteries. As such, I've had a few cases of meaningful imbalance in the last 2 years of operation. By meaningful, I mean high enough to cause a cell to go over the cutoff threshold and cause the BMS to tell the chargers to stop charging.

Note that these voltage imbalances didn't show up unless I charge to 90% SOC or greater, because of the shape of the lithium voltage curve.

I agree that active balancing doesn't seem to provide any benefit and is of questionable utility.  

2007 A54 #69
SV Tengah

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