The battery charger must be feed from the generator panel due to fact that that the generator no longer has a built in one. So you will need 2 runs one for the battery charger and one for the heater. you can instal the charger in the ATS and then only have to run one for the heater. hope this helps.
D Square Energy Systems
Is your company in Washington? I just saw your D Square signature there. I've sent a lot of our customers your way for service, and the ones who contacted me back all were happy with the service.