Hi, im hoping you can help with a strange little problem im having with my installation, I have 2 MP2 in parallel, A Smart Solar 250/60 and Cerbo GX with 12 pylontech batteries, I understand that Victron deliberately limits the charge voltage to 52.4v to save the pylons from themselves however, in my installation this is only providing 51.4v as reported by both the Pylon BMS and VRM, this leads to a cell voltage between 3.41 and 3.43 and seems to be stopping the batteries from balancing correctly, this imbalance is getting wider and now im seeing the new current limiting come into effect. Does anyone have any ideas how i can work around this without removing the CAN connection and treating this as an unmanaged battery?
Not really.. the charge voltage should be limited by the DVCC setting from the BMS, however, some multi’s are a little bit on the low side when generating the voltage. The Hard coded limit for the Pylontech batteries I think is around 53.5V. Your solar charger should be the primary charging element.
The Pylontech balancing current is only 50mA per unit. This is very weak for a solar based system.
Do check the programmed voltage limits in both the Solar charger (MPPT battery settings), and those in the Multiplus using VE connect or other Victron software (VE configure for the Multi).
Balancing the pylontechs can only be done by soaking at just below the max system voltage of 52.5 - 53.5V.
Thanks for your reply, unfortunately in the case of the Pylontech batteries, Victron chose to override DVCC value which is 53.2 as it is too high for longevity. This is documented in the Victron Pylontech setup guide. What I’m seeing is that the voltage on the terminals of the MP2 are around .5 lower than the MP2 should be delivering ands it’s keeping me just outside pylons balancing range.
FWIK, new Pylontech firmware supplies a CVL of 52.8V (3.52V/cell), not like the old 53.2V.
Pylontech starts to balance if any of the cells go above 3.36V, so even with 51.4V, given enough time, it will balance withing 30mV.
But it will not report SOC 100% if not at least 52.2V (3.48V/cell)
The algo was changed, it now tracks differences in cell voltage and adjusts the CVL.
New batteries may take time to sort themselves out. Leaving them on keep charged for an extended period can help.
Sorry for this piece of missing information, the installation is about 4 years old and was previously working correctly with the pylons requesting 53.2 and the victron targeting 52.4. There were some changes made to my home with the installation or an Air source heat pump, so over winter the batteries were discharged much deeper than usual and the cell balance started to drift.