[Richard]

Chuck,

The difference between then (lead acid) and Lithium is simply the rate at which the Lithium’s will accept charge. The much much higher charge rate of the lithium’s will cause the alternator to operate at a much much higher amperage. If you have the 50DN oil cooled alternator you will be OK, but if you have the standard 300ish amp Leece Neville or similar, I would think very much about trying to charge the lithium’s at all with the air cooled alternator. And if you have the smaller alternator with the simple belt arrangement that lacks a belt tensioner, don’t even think about it.

You also have to figure out how you are going to handle the sense voltage for the regulator since the lead acid chassis batteries and the lithium’s require two different charge voltages to remain happy. Set it for the chassis batteries and you could overcharge the lithium’s. Set it for the lithium’s and you never fully charge the chassis batteries.

When I put in the lithium’s I bought a programmable charge controller to prevent the alternator from cooking itself, but after really thinking about it, I did not install it. Instead I disabled the ability of the alternator to charge the Lithium’s, unless I manually engage the merge switch. That programmable controller is available if you want to play with it.