All I could find out on this is this:

The base eZee kit includes everything required to convert a bicycle to have electric assist, less the battery pack:

400 watt internally geared eZee brushless hub motor laced in a double walled rim
A 160mm disc rotor
Schwalbe Marathon puncture resistant tire and inner tube
Sealed 20 amp motor controller
Your choice of a thumb, twist, or half twist throttle
LED battery indicator,
An assortment of cable ties, spiral wrap, and a connector housing, for tidy wiring
There are then three battery options to choose from depending on your range and speed requirements, all of which come in the same low profile case with a locking ON/OFF key switch and a selection of mounting hardware

Looks like it was made in 2007 to now. The newer controller will take 24v to 48v. But could not find any thing on yours. Hope this helps a little. Do you know what year it was bought?