Originally Posted by dhealey
I'm upgrading my batteries from lead-acid to lithium and I need a new converter. If I have (2) 200AH 12v batteries that are each limiter to 50A of charge what size converter do I need?
I assume when you say limiter? you mean limited? That is the highest rated charge rate? Probably controlled by the BMS in the battery. In theory you could use any charger rated up to, or can be regulated to 100 amps. But you could also use a smaller one. Just takes longer to charge. Seems as you go up in amps the cost multiplies, A 100 amp charger does not cost twice what a 50 amp charger does. It's like 4 times.
If I were doing it, I would be looking at something in the 55-65 amp range. Unless you spend a lot of time boondocking and run them all the way down, and need to charge them quickly that would do it.
Voltage is actually more important than amps, because it takes higher voltage to get a lithium to full charge than a lead acid. So make sure you get one that is programable to whatever your batteries say is the proper charging voltage.