Following the 3.80 update this morning, I have noticed that the MultiPlus-II rises above 52.40V when charging my Pylontech US5000 batteries (firmware 2.3). Since upgrading to firmware 2.3, the BMS has been reporting a charge voltage limit of 52.80V instead of 53.20V. Victron’s policy was to cap the charging voltage at 52.40V maximum to prevent premature deterioration of the cells. As a result, the MultiPlus-II continues to force the voltage even though the state of charge (SoC) is already at 100% and the charge current limit (CCL) is 0A. Is this correct?
When reading the details of this update, I see:
So there has indeed been a change decided by Victron to raise the charging voltage to 52.80V.
With the original firmware, this seemed necessary to me. However, since upgrading to firmware 2.3, I have the impression that the BMS reports the battery as 100% charged more quickly than before. As a result, I do not know what to make of this change…
In any case, Victron now respects the limit set by the BMS (for the versions that have been updated). Was there an agreement with Pylontech on this matter?
Eww, Malaise thinks it’s far too dangerous to go by the battery percentage. Personally, I couldn’t care less about that; what matters is the highest cell and any imbalances, full stop. I’ve got a US3000B mixed with US2000Cs of a different age, and they’re not updated. I adjust the DVCC when the highest cell reaches 3.46–3.48, so the lowest one is 300 mV out, but that’s no big deal. Below 52 V, with DVCC at 51.7, it gets to 98%, which is enough.
Like when coming out of winter, if the imbalance is too great, bam—overvoltage.
Set DVCC to 52V in your GX and set in VE-config the inverters to 52V as well, that should solve your issue.
Read the pylontech settings at the Victron site, 52V will charge your bats to 100% full and will lengthen the lifetime as well, it’s even an advise to do so.