Hi,
I have the Magnum MSH3012M. I also purchased the remote which allows me to limit the 120 volt amps going into the inverter/charger.
The charger will work well on 15 amps--but I can "dial it down" quickly and easily.
The inverter works well with a Yamaha 3000 sIEB allowing me to run the generator in eco mode without significant voltage drop. I did choose to dial the input down to the 23 amps that the Yamaha can output.
The Magnum has a 60 amp transfer switch.
I was able to purchase the inverter and remote for $1880.00 including free shipping in the lower 48.
The air conditioner runs with ease on the inverter.
I did load the inverter with the air, water heater, fridge and OEM converter (by accident) voltage dropped to 100 and amps were 339 @ 12 volts.
After about five minutes, I plugged back into 30 amp shore power and saw 89 amps going into the battery bank.
I will be using the air conditioner while driving tomorrow and will have the generator remote beside me should the alternator show signs of being stressed.
I did run the fan only on the air conditioner to help "share" the dash air with the rest of the RV. That worked quite well for a 3 hour trip. The last hour I ran the roof air with the fan set to run.
This worked well to keep my class c cool upon arrival. I did go out for supper and did not keep the air conditioner on--and the RV went up 4 C from 22 to 26 (71.6 to 78.8 f). The heat from the exhaust and transmission radiate up from the floor.
In short, the Magnum will run any single high wattage load easily and with little fan noise. At 3000 watts the fans were quite loud.