Several months ago my boat started tripping at the shore power pedestal and since then I think I have narrowed it down to the multiplus, but I have been completely unable to figure out how to fix the situation or why the boat is tripping. Essentially the boat will be totally fine for hours or days and then with no change in power draw or circuits turning on or off it will trip. A few weeks ago I figured that maybe somehow the multiplus was drawing more current than the set input current level so I dropped the limit down to 10amps until the batteries hit 100% and then turned the current limit up to 15 so I could run some space heaters. Since then the boat has been fine, but we have some cold weather coming through this next week and I upped the current limit to 20amps and added a space heater. It was fine for about 16 hours but then the boat tripped at about 4am this morning. Between when I upped the limit and turned on the space heater no one was on the boat and no changes to any power draw or other circuits was present. Going through all the data on the VRM portal there is no distinct spike or change in any metric - just the power is on one minute and tripped the next.
In all I have tried:
- Replacing the shore power cord
- Replacing the shower power inlet
- Having the harbor come out and inspect the shore power pedestal
- Testing each circuit individually to see what causes a trip (boat will trip with only the inverter in and out circuits on).
- Testing for ground fault current - some is present but is limited - again this doesn’t explain why the boat can be fine for hours or days without tripping and then suddenly go.
At this point I’m pretty much at a loss for how to keep power to the boat. Any suggestions would be so appreciated.