My Dad bought an older motor coach which has a generator. The A/C unit would nearly stall that generator, it pulled over 30 amps when starting. I bought him a new A/C unit and the generator handled it easily, < 15 amps to start. Reefer units are power hogs, the newer they are the more efficient they are, but 600 watts is not going to cut it. I would (in fact I did) enquire about a TOU (time of use) power meter and offset all of the big power uses to off peak price hours. It saves me a bunch of money every month.