Brand new RV with 24v battery system. RV breaker panel has sub panel with inverter loops uncut from factory powering a portion of L2 circuits. Have a non-sub panel main panel coming, but don’t really think that’s the issue, just wanted to add some circuits for emergency battery charger and heater.
With the MPII in line with system set to shore and limited to 10 amps just about any load only on L2 will cause the breaker to trip, either immediately or within a few minutes. Cerbo only showing 1.1 amp AC load prior on input and no surge is seen. I did have just the fireplace light on with no tripping sometimes, but any other circuit enablement seems to trip the main shore breaker, not a GFCI trip. Both the fireplace and the outlet built into the main panel do not go through the sub panel 30 amp breaker. Fireplace and outlet share a split breaker also on L2, sub panel breakers can both be on and no tripping, assuming due to no load. I am converting from 50->30->15/20 amp via 2 dog bones, but have a 50->15/20 dogbone coming just in case. If I splice the wires to and from the inverter directly together everything works just fine, it’s just something with the MPII somehow. I have a 25ft extension cord (10 or 12 gauge) running to the RV and as it is not really close to the house and nothing else turned on or plugged into that circuit and the GFCI breaker is a panel type and not a sperate GFCI because it was nuisance tripping the GFCI prior to that swap, even with the RV not connected.
TLDR: Only L2 loads cause shore breaker to trip in any mode, splicing the lines directly together at inverter cause issue to not appear. 2 current dogbones 50->30 and 30->15/20. New single dogbone 50->15/20 on the way. Progressive industries hardwire surge installed also upstream of multiplus.
Just swapped L1 and L2 in the breaker panel and the issue remains on the same breakers, so it looks like It’s not the multiplus. Troubleshooting to continue… I’m now really stumped on what it could be since everything functions fine without the multiplus.
New dogbone adapter did not resolve. Bonded neutral bus bars together in panel with 6 gauge along with a 6 gauge jumper between the 30a breakers to remove factory inverter splice cable from equation. The AC ground bars are also both connected to the chassis from the factory. Can’t try normal breaker as house is for sale and this is the exterior outlets. About the only thing left is to disconnect the ground coming in from the circuit to see if that resolves. It’ll be a few more weeks before we have another trip planned and I can test at a proper 50a receptacle. I did verify both my MPPT and MPII are case grounded to the lynx distributor, the distributor is also grounded to the chassis.
It’s another case of the GFCI breaker being the issue. The wife had an idea to run the extension cord into the house and test on an outlet in the room that is no GFCI. This allowed all the circuits to be turned on and we could run the furrion chill cube AC without anything tripping instantly. We only ran for a few minutes so we didn’t get bugs in the house, but it was longer than anything lasted on the GFCI breaker. Need to raise this to victron engineering to help figure out.
This is a well-known problem using GFCI circuits to feed the AC inputs on Victron inverters. Current leakage requirements in the USA are more stringent than in Europe. Put another way, our GFCI outlets are much more sensitive. The Victron inverters have a ground leakage current that is about the 5mA limit of GFCI outlets in the USA.
The simplest solution is to plug your shore power connection into a non-GFCI outlet as you already found out.
I know this isn’t the answer you want, but it’s the answer you’ll get Victron is well aware of this. It’s only really a problem when plugging into a 15A or 20A GFCI protected outlet. If you have a 30A or 50A RV outlet installed in your garage it won’t be an issue since you won’t use GFCI breakers on that outlet.
Right, but everything I read said it trips the GFCI, this is tripping the breaker, not the GFCI portion and only when any circuits on one leg are turned on. It doesn’t matter if L1 and L2 are reversed on the main breakers the issue only affects the same half of the rv panel. That logically makes no sense as I’d assume it would travel with the L2 feed and it does not. And it affects any breaker turned on that is connected to a load even if off. The ground and neutral bus bars are connected so it’s acting like a full AC panel without a sub panel at this point. It’s not the feed lines since the issue stays if reversed and with everything tied together if there was a ground/neutral issue it would show up all the time since both are single bus bars at this point. Electrically speaking I can’t figure out what I am missing here.
Victron is well aware of this. It’s only really a problem when plugging into a 15A or 20A GFCI protected outlet. If you have a 30A or 50A RV outlet installed in your garage it won’t be an issue since you won’t use GFCI breakers on that outlet.