My Controller

The controller that came with the kit is awesome! It's specs are available from Samhyun (www.samhyun.co.kr):

Voltage: 48V
Control Type: PWM (Current control)
Current Limit: 40A
Low Voltage Protection: 42V
Throttle Voltage: 1V~5V
Operating Temperature: -30 ~85 deg.C
Cruise Mode: Manual/Automatic
Speed Mode Control:Low/High

When I got the kit, I didn't have my bike setup for the motor yet, so I played with it on my desk. I initially tried running the motor at 20V since I only had one battery pack at the time, but when I pressed the throttle the motor spun for a half second and then stopped. I figured that since the motor initially started spinning, the low battery protection turned it off, so what was the first thing I did after receiving the kit and trying it out? I opened up the controller! It's actually built really well (I think), even though I've blown two of the Mosfets (my fault).

Specs of controller internals (by inspection):
MCU: PIC16F73 Microcontroller (Haven't read out PIC program yet)
Mosfets: 6x STP75NF75 (75V, 80A, <0.011ohm Rdson) TO-220 Package
Mosfet Driver: 3x IR2108
15V Regulator: LM2575HV

Parts Hidden by regulator board (unimportant but not visible unless you take the board off):
LM2903: Dual Differential Comparator (for high side mosfet driver signals)
SN74HC00: Quadruple 2-Input Positive NAND Gate (for high side mosfet driver signals).

To change the low voltage cutoff, you have to change resistor R6, connected to input AN2 on the PIC. The initial value is a 15k ohm resistor which sets the voltage cutoff to 42V. I put on a 5k ohm resistor which makes the voltage cutoff around 14V (perfect since I was using a 15V power supply for some testing).

The controller has lots of wires coming out of it, and a few vias inside it which are obviously made for wires, but aren't used. I have decoded the wires to be:

PAS: Pedal Assist System (not sure how this is used, but there are three wires coming out of controller)
Throt: Throttle
SPD_LMT: Speed Limit
CRUZ: Cruise Control (Vias only)
Brake: Brake Cutoff (I connected this to the red button on the throttle)
Single wire from Voltage Regulator: Voltage Display on throttle (uses the ground wire from the throttle connector)