Originally Posted by TitanMike
Lithium batteries generally have a .5 C charge rate recommended.
2x 100ah batteries will charge well with 55-60 amp converters. Larger converters require larger 120 volt supplies with "12 awg wire and 20 amp breakers. Most stock converter wirjng is #14 awg and 15 amp breaker.
As suggested, check to see if existing converter is lithium capable.
If not I'd suggest a converter like the Progressive Dylamics 9160ALV and mount it as close as practical to the new batteries.
Extending the 120v converter wire to this new location is a lot less expensive than upgrading 12v wire to at least #4 awg welding cable and yields a the fastest possubke charge times.
This is spot on. 2x100Ah LiFePO4 (LFP) should handle 100A charge just fine. Hard to get that in a standard converter/charger. My 5er has 10 ga wire for the converter/charger AC input and a 20A plug but they installed a 15A circuit breaker for the converter/charger. So my limit for off the shelf converter / chargers was 60A. Above that, they go to a 20A AC cord. 60A will get you from 20% to 90% in 2-3 hours with 2x100Ah LiFePO4s.
I got the Progressive Dynamics 9160ALV which is 60A and it was ok. Kindof caveman in that it is two stage but not adjustable. And it is LFP only, so if you want to take your LFP with you to your next camper, you are SOL. Couldn't find a better option, but others should chime in.
I now have an inverter/charger and got rid of the converter/charger. My inverter charger (Victron Multiplus II) is a 120A charger and I have pushed that much into my 2x206Ah SOK LiFePO4 batteries.