I have a Multiplus II 3000W 12x120V and I have a strange problem with AC2 being super picky about the frequency from the generator. AC1 is not picky, only AC2. It will always pass shore power through, even if plugged into a long extension cord such that input AC is down to ~110V. but the generator is unreliable.
The generator is an Onan 4000W and it is 15 years old, but it runs well and produces good power at 60Hz +/- 2Hz. I just took it to a service center and they confirmed the generator is running well. The inverter will always accept power from the generator or shore power to charge the batteries and pass voltage through to AC1, we only have issues with it passing power through to AC2. If the generator Frequency is not right at 60 Hz it will take power from the generator to charge the battery, and it will pass that power through to AC1, but it will not activate AC2. I can adjust the governor and get frequency right at 60 Hz, and then it will work, but the next time I start the generator it might be 59 Hz or 61 Hz, and then it won't pass it through again. It is very frustrating because when it is refusing to pass the power through to AC2 I can measure the input voltage and it will be 120V 61Hz with no load (which is what the generator service manual calls for). I am about to just bypass AC2 and have the generator directly power the air conditioner, but then I am concerned about the charger and microwave overloading the generator.
Thanks.
