Charging rate elec question

Thanks to all that responded. I was concerned about getting the wrong thing specifically getting to big of a system and causing other problems as this is a tiny Class C(Majestic). Wiring has been worked on(spliced, bad connections etc) so was going to clean up and put in converter charger that would re-charge faster. Only has one battery right now (group 27)and that does us usually one night in winter. Don't like running genny at 3/4 of gallon per hour. Going to add one more battery and something that charges faster. Currently have Parallax model 7345 and label also states "Average charge rate 5 Amp" so want to double battery power and reduce charge time. Should pay for itself pretty quick not to mention getting rid of "spaghetti" mess of wires.
Thanks again