I’m using a normal pro sport 12v charger on cranking battery. The Lithium Pro M1238 running charger is connected between both batteries. When the Pro Sport tops off the 12volt battery,(13.2volts), the Lithium Pro running charger then receives the volt from the Pro Sport, converts and charges the 36volt battery. This is all AC power..

when boat is running, the alt/gen is charging the cracking battery..volts is being passed to the M1238 charger all the time when the boat is running and it’s continuously charging the 36 volt battery as long as engine is running.

Factory ProSport will work perfectly..don’t have to send it off for programming etc...just make sure that you hook up all three out put leads(banks) to the cranking battery and have correct plug in selector hole of AGM..if you don’t, the logic of the charger will make it go into maintenance mode before it ever reaches 13.2 volts- which the Lithium Pro M1238 must have to be turned on and work...I went 4 months thinking I was charging my 36 v battery, and wasn’t...the Pro sport needs all three leads connected for its logic to work properly..