Welcome to the forum...
If there is a kit I haven't seen it yet. Basically you need a controller that can handle 48 volts, 48 volt solenoid, 48 volt battery pack and 48 volt charger. You can get by with the 36 volt solenoid and charger but if you want to do the job right your best bet is to go with upgrades on the solenoid, charger and 4 guage cables.