air con power consumption

Hi all

We just picked up a near new Supreme Spirit caravan. It has a Wren reverse cycle air con mounted on it. It seems to work well on mains power but I was wondering how much grunt I would need to run it from a generator such as a Honda 2.0 or a Yamaha 2400. I know I will need more than just the air con but as far as I know the 12-240 volt fridge and a few lights wouldn't draw much. I certainly wouldn't be trying to run microwaves or other power hungry appliances at the same time. The book that came with the van tells me the Wren power requirements are maximum 6.5 amps at 240 volts. According to my rough workings out I would need about 1600 watts continuous. While the Yammy would seem to walk this in the unit is very heavy compared to the Honda. I wouldn't buy a cheaper brand even though others have reported good runs with some of them. I have also heard a lot more horror stories to go with the good and knowing my luck I would get the lemon.

Thanks in advance for any help.
Cheers Pop