Hi, John. Charger must match to the battery by two parameters: volts and power. If batt has 36 volts, then charger has to be 36V. Power of charger( A - amps) has to be betwen 10%-20% of batt. capacity i.e: if battery has 600Ah capacity, then charger has to be 60A to 120A for fast charge. Most of new generation chargers built in high frequency technology has electronic boards which automaticly recognized capacity of batt,voltage, level of discharge and match all those parameters to the condition of battery.Choice of power supply (single or three phase) depend of what type of connection you got in your warehouse, and dont affect charging. Remember that bigger chargers need bigger power supply,for example: 48V 120A charger with single phase connection need arround 32A power supply, where the same charger but with 3 phase supply will take only arround 8A per phase. Hope it helps you to choice the right one which suits you.