Hello everyone, could someone please help me solve this strange problem that sometimes appears on my home power plant? Today, July 12, 2025, during the night, at 5 am, the distribution network was connected to the inverter and the network did not have a failure. The power failure in the house was caused by our MPII 48/5000 inverter. At the time of the failure, the battery voltage dropped from 53.22 volts to 42 volts! See. the attached picture. So these battery voltage data are VE.Bus System Voltage (V). Just before the failure, a current of 44.9 amperes was drawn from the battery, which was approximately 2400 - 2000 watts. At this time, at 5 am, there was no reason for such a high consumption of electricity in our household. The only thing that could have been on at that moment was the submersible pump in the well, which starts after each toilet flush and pumps water until it reaches the required water pressure and then automatically turns off.
Apparently what happened was that the battery voltage dropped to 42 volts, which is of course below all limit levels in the ESS assistant. See. attached picture.
Interestingly, if at the same moment, i.e. at 5 am, I read the battery voltage, it is recorded in the system directly from the battery instance ( 16kWh, SEPLOS 2.0 BMS, 16x EVE MB31 cells, NEEY 4A active balancer ), so the drop at the time of the outage was only to 52.8 volts. So I don’t know what to believe, whether the VE.Bus Voltage data or the battery instance.
From the inverter’s perspective, the battery voltage dropped to 42 volts, which was the reason for the power outage in the house, even though grid voltage was present at the time.
I forgot to mention an important thing here, that at the time of the outage, the High DC Ripple error appeared. At the same time, the Low Battery Voltage error also appeared.
Interestingly, at another part of the day, when we have a sudden power draw much larger than at that moment at 5 am (for example, a 2000W kettle and a 2000W electric oven together), there is no power outage in the house and everything works without error.
Not all batteries end their voltage realtime.
Some read their voltage before their disconnect point.
Just guesses here as i haven’t worked personally with the brand battery you are using.
This is my indicator that the DC is not providing/absorbing the amps needed. (Maybe it caught the battery sleeping )
A pump is a completely different load type to a kettle. And can be problematic as the have back emf which needs to sink somewhere.
Hello LX, thank you for answer. It is interesting thing. Maybe this issue come in time when NEEY Active balancer is working, is balancing cells ? Can I improve my installation with following: ?
Do you think that if I set at least 50 Watts (or rather more, e.g. 100 W) in the ESS settings, in the “Grid setpoint” section, so that the inverter would simply draw current from the grid permanently during its operation (the direction of energy flow would simply be directed from the grid to the inverter) and if there were a sudden energy consumption in our household, the direction of that flow would allow it to more easily suck the necessary energy from the grid if for some reason the battery was not able to supply the current energy need?
The question is whether the inverter would be able to quickly regulate the acute energy need.
I always thought that if the grid is connected to the inverter in addition to the battery, the inverter can never fail.
But I understand that the Victron Multiplus II is a device that is not made to work without a battery. Goodwe, Fronius Gen24, etc. can do this, for example.
That the inverter would simply always rather take energy from the grid than from the battery.
)