Multiplus low battery / over load while inverting

DIY
,
1

Hi all
I picked up this 7 year old Multiplus 12/1200/50 and I have been testing it out and it seems to charge my lithium 200ah at 40amp until it was fully charged without any issue (battery is brand new)

But when I tried to invert from the battery it worked fine for the first hour (13.4v) but then i started to low voltage alarms and overload alarms I was only drawing 100w AC at the time

I’ve checked the cabling and connections and all are clean and firm I did notice when it overloaded the dc it blow the 100 amp mega fuse I had in-line

Could my Multiplus have an internal short or conversion issue causing it to act this way

Thanks
Justin

2

What is your cable size between battery and multiplus?

3

The sane one that came with it. Same size and length with only the fuse and shunt between the multi and battery

4

Did you buy it from @DuivertNL otherwise how would he know what cable that is? Please add a clear description or better. Add a picture of what you see on that battery wire. TIA.

Also. Blowing a 100A fuse is really bad. Something is obviously wrong. Have a multimeter handy? Please check all wires. Must be something wrong. Hopefully not the Multiplus :grimacing:

5

The cables are 1.5m x 25mm2

And I have checked all cables and connections for resistance and all are as expected

And i agree for the multi to surge like that and blow a 100 amp fuse at sure low power draw makes me think the multi has an internal issue