Relevant to your interests.
Xtreme XB-600 (electric scooter mods)
In a few weeks I will be upgrading to 72 volts, and replacing my 60 volt charger with an array of 12 volt chargers.
I've replaced all of my batteries once so far.
There's much more discussion of XB-600s on this forum
http://visforvoltage.org/forums/elec...00-xb600-xb700