Balance two lifepo4 BN52V-100-5.2k DU

hi, i have two of those with a sunsynk 8kw inverter and they are not balanced, see image - any ideas on how to do that?

If that was mine, I would have drained them both to 20%.

If one bank is still higher, would have disconnected the lower one, draining the higher one to the same SOC as the lower one. Just to speed things up.

Then reconnect both, recharge back up to 100% SOC, slowly, low charge amps.

Once charged, would have used them lightly, like 20% max per day, still lower amps, so that the BMSs have enough time to balance each bank’s cells out. Would have done that for a few days, as long as it takes IF I see a difference that is.

Once they are closer, would then have left them on Keep Charged for a week or more, to “touch up”.

I would just leave them… SOC is an estimate anyway, and in time I expect them to converge.

They should get balanced once you charge them fully - or they should both get to 100%. Are they connected with comms?

tx guys, i’ll investigate inverter settings, alternatively charge them separately to 100% and see how it goes… i’ll report back in case someone might sit with the same situation - no crisis though as they both get full marks for health, whatever that means :rofl:

Ain’t that the truth!

Yesterday, BMS says 100% SOC … BMV says 70%. :rofl:

But I’m ok with that, 95% of the time, the two are close as damn, the BMV is the “driver” of the system.

i got the guys from blue nova to rectify settings via wifi. everything is now within <5% , will see how it goes.
excellent service, took me two calls though :slight_smile:

the battery imbalance saga seemed to have been addressed - it was a comms fault between the inverter and the bmac - the blue nova battery management module - the result is obvious on the img - will be interesting to see if they drift and how.

as soon as the comms cable between inverter and bmac was damaged the drift started again and was solved with the replacement. take care of bad/sloppy workmanship especially at the connectors or if things are squeezed in to too narrow spaces and then covered with good looking trunking covers!