Brand new Multiplus Compact 12 / 2000 professionally installed in my camper, I’ve had it for about two weeks and I noticed what looked like mud on the lowest edge of the case (it’s mounted horizontally). After disconnecting it from power, I popped the cover off and the inside of the case panel has some char marks where the LED indicator cutouts are, and what looks like mud spatter on it, and some of the components appear to be heavily corroded.
Any idea what might have happened?
With that level of corrosion i would question its age. (What is the serial number?)
If it is mounted horizontally how did stuff accumulate at the bottom of the case?
And that spray pattern on the cover looks like capacitor venting.
The slightly smokey look near the switch is suspicious as well.
That is a definite ask questions of the installer need here. Something bad happened to that inverter. And it does not seem new.
Is the schematic drawn on the inside side of the panel?.. 
It seems to be a 5 year old unit.
Its definetly not new… serial is hard to see, 2020?
Thats what i thought too.
Noting how clean the legs of the switching fets are, this unit has not seen much use - even if it is an old unit. I recently serviced two compact 24/1600’s, and they were 10yrs in service, with significant dirt build up on the legs of the fets. Heatsink clamps are nice & shiny too.
A picture of the control board around the switch would be interesting - to see where the black mark comes from.
@alexpescaru : Yes the schematic is on the inside of the lids of the compact series.
The withe splatter on the inside of the lid does look like a capacitor blowing out, so check the three(?) big caps in the middle of the heatsinks - if they can be seen - could be hidden by the control board.
I would also take a peek under the ac board - at the bottom of the first pic, to see if there is anything between the board and the case - anything in there can cause the ac to be shorted to ground - or another part of the circuit.
Thanks for all the great input! The inverter is being replaced by the installer but still, I find this to be a compelling mystery. I had only very light use of the inverter for a camping trip, although the installer demo’d it with a heat gun when I initially picked it up.
The serial number of the inverter begins with HQ2041, which I presume means this inverter was manufactured around October of 2020. The installer said it came directly from an extremely well-known battery manufacturer who also doubles as a Victron supplier. The install was performed a month ago and, of course, was implicitly understood to be with brand new equipment.
Either something nefarious is going on, or someone legitimately messed up. I’d just like to know the truth one way or the other so I know if I need to avoid this installer, or they their supplier, in the future.
I am awaiting an explanation of this and will report back. In the meantime, I suppose I will need to examine the other Victron components that were supplied as part of the install (DC/DC charger, Solar charge controller, Cerbo unit, etc) to make sure there are no surprises under the cases, and that the serial numbers do not track back to ancient backstock, returned or stolen goods, etc. I wonder if there is someone at Victron who can help with this.
Not something I particulary wanted to do; if I had the time to monkey around with the components to this degree, I certainly would have just done the install myself.
I’ll get a few more pics of the inverter once I get myself yoga’d out, upside down with a headlamp and screwdriver, and crammed into the electronics bay again.
Yes i would check all serials, datecode is like the inverter you already checked
You can also check serials here to see where they were sold
