I have a solar sytem consisting of 3 x Multiplus ii (3 phase) Fronious 10K grid tied inverter Cerbo GX and 8 x us5000 Pylontech batteries.
My problem is as follows:- if there is a grid failure on one phase or a major imbalance between input phases the the system goes into alarm status on batteries and can only be reset locally by switching off the Master batteries to initiate a restore and clear the alarms.
why do the US5000 batteries go into alarm status (internal error, high cell voltage and cell imbalance) when grid input becomes unstable. (all clear when reset)
is there a way to clear the battery alarms remotely through Cerbo GX as the property is a holiday home so local reset is not possible.
is there a setting that would stop this from happening as in Spain the power fluctuates quite regularly.
I reduced the charge current to zero to stop the batteries frem charging until it can be reset.
Were the batteries (almost) full at the time? And is the Fronius Inverter feeding in excess solar? If so and the grid fails, the Inverter has no where to put the energy but the batteries and the battery voltage will rise quickly, leading to high voltage alarms and the BMS switching off the charge MOSFETs. Reduce maximum SOC to 80% and/or set the charge current to a value where the batteries will only become full in the evening.
Yes the batteries were SOC 100% as the property is unoccupied and panels are producing 9kw mostly being feed back to the grid.
When i return I’ll try what you suggested as it makes sense.
I hope by leaving the batteries in alarm state for a month is ok. I have reduced the charge to zero so they are really sitting idle and house is being powered by grid and panels.
The batteries should come out of alarm over night, if there’s sufficient consumption to reduce the voltage to below 3.4V per cell (51V with 100% balanced cells).
The batteries are down to 56% SOC and 49.9V. Still indicating 4 alarms - all internal failure and 3 modules blocking charge/discharge out of 8.
I think a local reset of batteries is the only fix.
Could I sent you a private link and password so you could access the system and get your opinion.
Are you running ESS?
It would be worth checking the min/max cell voltage widget to see how big your imbalance is.
If you have configured the system using the config doc:
And the inverters are configured correctly as a 3-phase system, it should just work.