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We have a Multiplus II -3KvA connected to a 4.8KWH 48v lithium battery. SEC
we are not using communication between battery and inverter but treating it as a lead acid with correct charging parameters. The system is set up as a back-up system.
When battery gets to full - around 5a input - the inverter shuts down totally - no warning leds - both ac and dc shut down - and inverter has to be switched off and in again to reset.
is this an inverter fault or a setting fault -please advise
Is it possible, that there is a overvoltage shut down?
If the DC voltage is shut down to, i think first the Battery switch off. Not the inverter.
Regards
Markus
Hi Markus
thanks for the suggestion
The battery does not seem to react at all - only the inverter. It also only happens with the MultiplusII - not normal Multiplus. I am now having the same situation with a 5KvA Multiplus II
I have the same problem! My setup is as follows:
If the battery is charging, everything works fine. The power from PV inverter loads the battery and the grid. If I unplug the grid only the PV inverter loads the battery. But if the battery is full the MultiPlus-II shuts down and is showing overload and battery low at the same time.
Is Your PV inverter made by Fronius?
Does your PV inverter understands the frequency shift signal from MP-II?Did you load an assistant that would let the MP-II communicate with PV inverter using frequency shift?
MP-II will shut down if battery voltage gets over the top limit for the selected chemistry.
Hi There. We have the same problem with a multi 11 5kva 48. It is connected to a Lithium. Voltages are correct. Everything works fine until batteries are full and then the inverter shuts down with no warning. There are no coms connected here either just correct float and bulk voltages set, lithium ticked etc. Please could someone from Victron Help.
Thanks
Peter Burden
SolarSells SA
MD
Hi @colin mackay,
Can you explain why you charging Lithium battery with Led-acid settings?
Inverter will shut down when battery voltage gets to high.
Does this SEC battery have an internal protection?
I also have the issue of the Multiplus-II 48V 3kVA shutting down. It needs to be switched off and then back on again to recover - not a usable mode of operation in a UPS application.
I don't know the reason of the shutdown but noticed that when the Lithium battery in near full charge, some cells reach a higher voltage sooner than others. In this case the BMS turns off charging, rebalances the cells, and then resumes charging. During this time, the charging current from the Multiplus is "not accepted". I've observed this many times, and the Multiplus did NOT shut down. So I really do not know what's causing the shutdowns (twice since installation 6 month ago).
Is there a way to "automatically" turn the unit back on after a shutdown? Of course I still would like to understand (and address) whatever is causing the issue.
Perhaps this post of a situation I encountered may help. I have encountered a situation where when Lithium batteries reach a certain voltage, one or more cells may reach 3.7v and the BMS open circuits that battery to prevent overcharging of that cell. This causes a variation of DC voltage. Although in my case it raised a DC ripple warning, it isn’t actually DC ripple but rather a varying DC potential. This causes a Quattro to switch off and then switch back on some time later. Rarely it causes a fault condition that cannot be resolved without a reset.
The problem is exacerbated when batteries are in series to achieve a higher voltage and each battery has an internal BMS as the batteries can get out of balance without any overall BMS to balance them.
The problem was resolved by reducing the absorption voltage to keep the BMS units inactive. When they start switching the Quattro didn’t like it.
The post outlining the situation as I see it is here.
https://community.victronenergy.com/questions/129138/quattro-shutting-down-lithium-batteries.html
I hope this may help a bit.
Regards
Trevor
