I have a MultiPlus II 12v/120v connected to 12v LiFePO4 batteries (four 100ah CHINS). It has worked flawlessly for 2 years now in our bus conversion. When I switched the inverter on this evening, it immediately set the Overload light. The only load that might have been applied was a pair of 15w LED light fixtures. I turned the inverter back off, flipped the main breaker off, and tried again, same Overload light.
Connected the bus to a separate generator, and everything works as expected (so I believe I can rule out any shorts in the electrical system, otherwise I assume it would have either tripped the generator's 20a breaker or started a fire).
Troubleshooting in the Manual for the Overload light only suggests to "reduce the load." Where should I start looking to solve this?