The Generac's that used to be installed in TC's by Lance and others were 3600 watts. It looks like Generac has gotten out of the built-in RV generator business though. Honda also left that market a few years back. It looks like the only manufacturer of the smaller built-in RV gen-sets that you could use in a TC now is Cummins Onan.
2500 watt is probably about as small as I would go, but it's going to be dependent on what you expect to run on it. If you want to be able to turn the A/C and microwave on at the same time the reefer is running on AC power and the battery charger is pumping out max amps, 2.5K might not be big enough.
:):)
