You also have to match the converter or charger to the ability of the generator to supply the 120v to run the charger at its rated DC output. Big amp charger needs a big watt gen. With that, you can also choose a PF corrected charger to be able to run more DC amps from the same amount of 120v.
The first thing is to decide how long you want to run the gen for how often while camping.
Your daily AH usage from however big your battery bank tells how long before the batts are down to 50%. Then you will do a "50-90" recharge and we know how long that takes for various "charging rates" (DC charging amps wrt AH size of bank)
Now you pick a charging rate that fits your chosen recharge time for your size bank, and get a charger/gen combo that can do that.
