Hello John!
Actually zygmunt's reply is very professional. In my opinion, I suggest your charger's voltage could be "36V" and its Ah could be "20%*the Ah of your battery". Its imput voltage could be 110V/Single phase. (PS: Ah=Amper/hour)
For example, if your battery is 36V/400Ah, your charger could be 36V/80Ah and its imput voltage could be 110V/Single phase.
Michael
HYTSU GROUP
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