Cheap Controller Base

[BrandonB]

Recently I bought a floor buffer motor on eBay to toy around with driving a motor through the gears on my bike in an attempt to get more torque. The only brushed controller I have is the huge YK42-3 that I did not want to or have the room to use. I spent a few days scouring eBay to find the cheapest controller I could muster. I ended up buying a Yi Yun YK71 for just under $16 shipped. This controller is TINY and only has a power rating of 250 watts. It arrived from China today, and I cracked it open to find this:

I have labeled the common parts for modification in the picture because of poor lighting conditions. The controller has many SMD components, but the most frequently changed components are very easy to access and change. I realized that the single FET design of this controller would put a severe limit on low much power it could handle, but then I remembered the Brute Force Xtender that was designed and successfully implemented by FrankG in the Dirt-E bike conversion.

I plan to stay with a 36 volt operating range (Maybe 48 volts at some times) because that's mostly what I use, so I plan to use some IRFZ44Ns to customize my own version of the Brute Force Xtender that will enable me to have a 36 volt controller that will handle ~1500W of continuous for around $30.

I thought others may find my findings regarding this controller useful, so I decided to post what I found. Feel free to delete it if it's irrelevant.

 

[heathyoung]

Upgrading a brushed controller is a cinch. You would just run multiple mosfets in parallel but have their gates triggered through a series resistor of about 3 ohms or so from a common point. It will be low frequency PWM so you shouldn't have too many problems with gate capacitance being an issue, worst comes to the worst you could make a totem pole driver with a pair of transistors being driven by the gate pulses. Low frequency makes it easier to have your power devices furthur from your drive logic if need be.