It has a low voltage cut-out and will not work below 21V.
(The low voltage cutout can be changed with a simple modification (see notes)).

Only 7 wires are used for the speed controller function: Battery connections, Motor connections, and 3 wires for the motor speed controller potentiometer. These units require a pot & resistor (not supplied) if a THROT2 motorcycle style throttle (not supplied) is not going to be used. Other optional connections are for disabling the controller (switch on brake), power for auxiliary circuits etc. We do not supply any additional connectors, just the modules as pictured. Connectors can be cut-off from the bigger module, the smaller module easily comes apart (4 screws) and the terminals can be easily be soldered to.