I recently replaced my original deep cycle lead-acid marine battery for a 100AH Lithium Iron Phosphate battery. As others have said, the "full charge" voltage of the LiFePo battery is higher than lead-acid, about 14.4-14.6V. The car cannot over charge it. I upgraded the DC converter in my 2008 Aliner to a newer one that had a setting for the lithium battery. I also added a solar panel and charge controller, as well as a cutoff switch for the shore power charger. This last bit was to insure I am not constantly "floating" the lithium battery at 14.6v while I am connected to shore power for extended periods. One of the main reasons I wanted to switch to a higher capacity battery was so that I am not completely draining it while driving long distances while the fridge is running on 12 volts. The fridge draws about 10amps while on DC. I have found that with the tow vehicle running, about 5 amps is being supplied from the tow vehicle. This halves the amount needed from the camper battery. The solar panel can add an additional 2-3 amps while driving on a sunny day. I can monitor the charge/discharge current and battery voltage via Bluetooth while driving. Getting ready for a 5000 mile road trip for the eclipse and I expect this upgrade to help a lot on future trips as well.
Bruce Beford N1RX