Multiplus 2 Inverter 48V 5kVA was running well for a few months.
Battery voltage reached 68V and Inverter turned off, after voltage dropped to 64V inverter can’t be turned on.
Moved Inverter to bench and supplied 63V from power supply, Inverter doesn’t turn on, and no current draw is present.
No LED indicator is available, and Interface MK3-USB-C does not connect
Disassembled inverter and took out mother board which has no visible damage anywhere.
How can inverter be reactivated?
How did the voltage even get into this range… 68V is already very high… and the 66V specified in the data sheet is already the absolute limit…
I don’t see any chance for the Multi… the internal electronics will probably have been damaged.
Hi Steffen,
my charge controller got damaged and didn’t stop charging at selected 65V but 68V instead.
MP2 did shut off at 66V before but came on with no problem when battery voltage was set to 65V.
There is no visible damage on the MP 2 motherboard, the little red round fuse is ok.
Also input caps are 390uF/100V and Mosfet 072N10N also 100V type.
68V should not damage anything if MP2 max voltage is 66V because design sure has some margin built in
Thanks, Rich.
Hello Steffen found a problem on the motherboard after all.
The power supply sub-module MGR18-SMPS-V2.12 has a blown-up chip (U12).
Now I have to change the whole motherboard to get the MP 2 working again.
Unfortunately, I have 3 dead MP2 in my system, as always when it rains it pours.
I would like to see a protection craw bar circuit, added to the MP 2, probably do it myself when I get the replacement boards.
When battery voltage exceeds max input value the MP 2 can really handle, create a short via SCR the blows the little red fuse on the mother board.
This will disconnect all electronics after the fuse from battery and no further damage can be done.
After battery voltage is back in range, changing the fuse will restore MP 2 function.
Always something, Rich.
Hi Steffen,
my charge controller got damaged and didn’t stop charging at selected 65V but 68V instead.
MP2 did shut off at 66V before but came on with no problem when battery voltage was set to 65V.
There is no visible damage on the MP 2 motherboard, the little red round fuse is ok.
Also input caps are 390uF/100V and Mosfet 072N10N also 100V type.
68V should not damage anything if MP2 max voltage is 66V because design sure has some margin built in
Thanks, Rich.
Why is your charge controller at 65v? Does your battery need that high voltage? Your really pushing a 48v designed system to the max with little to no room for errors…
I would not be surprised the 66v is a hard limit, victron mppt’s also have a hard limit, they fail if voltage exceeds this limit (a 150/35 mppt will fail if pushed over 150v)
@rbachf What battery bank do you have to get such high voltage? Repurposed EV?
Yes, it looks like 66V is a hard limit for the MP 2 and 68V destroyed the motherboard.
Power supply sub-board MGR18-SMPS-V2.12 has IC U12 blown apart, no other visible damage
My battery is built from 19 lipo4 cells and has 69V max voltage but will now only charge it up to 64V
Also add automatic solar panel disconnect if battery voltage goes to 66V in case another charge controller failure in the future
Now I need to find new motherboard to replace damaged one, any advice where to get it from
Your Victron dealer can submit a non-warranty claim with Victron to obtain the board. If you don’t have one, submit a request on the Victron website and they will find the seller and they can take it from there.
I advise you to make the voltage much lower than 64v, you are going to destroy another with such high voltages…. Your asking for trouble in my opinion 
Is there any reason for such high voltage other then the battery you are using? Is it a diy battery?
Thank you for the info regarding new boards.
The battery is diy and I designed it with the specified max voltage in mind.
The system ran well for almost 3 months with 65V battery voltage but 68V did it in.
Will investigate more on reasonable battery voltage.
What kind of BMS do you have?
I would say that 16S is reasonable and 17S the absolute limit. Or get yourself a couple extra spare parts. Costing hundreds of euro each. And please note that you may run into additional issues on other PCB’s.
I personally would not use more than 16 prismatic cells on a normal BMS. I ran a 96V setup for three years, with two inverters, and it was nothing but trouble.
The jK-BMS can handle up to 24 batteries and don’t plan on blowing up more boards.
Since I have bad MP2 motherboard I will do some reverse engineering to figure out the limits
Just ordered a desoldering gun to get the sub boards off and see what I can learn
In the meantime, will run system with lower battery voltage