Any of you racers used one of the 2000 watt portable generators

yep. I have the charger. That is how i use the golf cart when i race. Stick the charger into a wall socket overnight, fully charge the cart, load it and use it at the track.
Couple times a year i go to a 3/4 day event( Monster Mopar at Norwalk, Moparty at Bowling green)
Its possible at one of those events i might not have access to electricity, and my golf cart needs charging over a long event with lots of use. Hence my interest in a portable power source to plug my charger into i can bring along
Guess i didn't realize this was so hard to explain
Sorry for that. I thought you were trying to charge the 48 volt battery bank with the 12 volt genset. As long as the genset output is close to what the Golf Car charger requires you are golden.