jtad wrote:
It shows I'm drawing about 8 amps with both roof air units off...
Assuming everything else if off, that's almost 1000 watts, which indicates your charger is working hard.
When I had this problem with my Prosine 2.0, I changed the "Ac breaker size" parameter (in the control panel) which dialed down the amount of amps going to the batteries.
See if that helps.
That said, a generator that big should be able to handle it just fine. Anyway, it's worth a try. I don't know how big Onans handle surges.