I don't know how you got a 12500 BTU to run on a Honda 2000. The draw needed to start the compressor is more than what the Honda 2000 can put out. Did you add a capacitor to handle the start up electrical load?
I'm looking for a make and model of a rooftop A/C unit for a cargo van, that can be powered by a Honda 2000 watt generator. Everything I've seen online so far are 11K BTU's than need 2500 watts minimum. Anyone running what I'm looking for?