Upgrading from group 27 to golf carts

Thanks for all the replies. I realize I should not go below 50% SOC, hence why I am wanting to upgrade my small battery that is getting over worked and heavily depleted. Don't worry Roy, I don't have a diode isolator for that exact reason on the voltage drop. Maybe I wasn't clear on the charging voltage... Say I stop draining the batts at 50% SOC, then I use the generator. I was hoping to set the charge wizard to 13.2 volts for a few hours to keep the current at around 20A. Then, after that set it to 13.6 for 2 hours, still around 20A and hopefully even at 14.4 volts it will still not go over 20A. Maybe I'm dreaming. I do know the importance of having full 14.4 charge voltage, what I am hoping to get away with is having a constant current method of charging... 2 hours at 13.2, another 2 at 13.6 and then setting it at 14.4. After this, hopefully leaving the converter to decide the best voltage.

Thanks guys. Maybe I do have to bite the bullet and get bigger generator. In my imagination, the batteries charging over night before the trip, driving with a powerful alternator, and having a small top up at the campsite for a few days was going to be enough.