[Coley]

Hook your chargers up in series. Add a 6 volt charger if you want to gas the batteries a bit.
I bought a 48 volt Club Car charger on eBay and it worked well.

 

[Coley]

You might want to add a 6 volt charger into the mix, as you need more than 48 volts to charge a 48 volt pack and be able to gas the pack a little.

The charger is almost the most important addition to your vehicle, once it is built.