A Cheap 350w BLDC Board with Regenerative Braking

[XavierBetoN]

Very useful information,
I am building my own ebike without the heavy bulky controller, I got the new blue pcb version (36v 500w) of your small controller from ebay which I bought for 14 amerikanski rubles and was searching for how to implement regen to it.
I don't like to have a heavy bike, so I went with the lightest motor, lightest controller, and lithium cells inside a tube without BMS.. I just pull out them and charge in my 18650 charger.
Instead of thumb throttle, I fixed a slide potentiometer onto brake lever and put inside the potentiometer a pen spring for making it a throttle slide.
Whole system is 180gr including the motor, excluding the batteries. Drone motor is attached to where V-Brake attachment point is on the front fork, and 3d-printed 622mm gear to stick at cheek of the rim using a semi-metal/PLA filament.
Tests worked out well, I just need to decide whether to use 2x8 18650 or 8 27700 cells.. After that will test ride and produce a video hopefully.
Cheers m8

[maukaman]

Great explanation of this. This makes these cheap little controllers even better to be able to get some potential regen from them.
Thanks

[jcreedy]

Those KT controllers are supposed to have regen as standard but only through the use of a KT display. I thought about getting one for the purposes of obtaining the regen function and glad i didnt. As I found on my current 36/48v 350w slightly smaller sized china controller if i simply ground the EBS solder pad It activates the Regen function when operating the brake cut off switches. Pretty much every one of these cheap controllers has lots of functions you can activate. There all pretty much manufactured from the same schematics and then functions are added as per requirements of the retailer. But they all seem to natively support Regen, cruise control, reverse, 3 speed function etc. All you go to do is get a wire and ground each function or add a switch inline. The regen on my "MAGT" controller is quite powerful, more so than I thought! All though this could be due to the large shunt mod I did to it. Not sure if shunt mod effects regen as well as power output, but in any event its quite decent! If you have a cheapy china controller you can add regen by shorting either the EBS, EABS or the F4 pad. Some controllers you have to solder the X pad to the DS pad.

[franciscobugna]

How do you have the throttle conected?

[danielauen]

Could it be possible to retool a cheap controller like this for high current regen? so you can hook the motor up to an engine and use it as a 40+ amp generator, but also use it to start the engine? Could use something like a 3 phase rectifier, But thats unregulated, and cant start the engine with that. Thought about using a cheap controller to start the engine, and then use some big chunky switches to disconnect the controller and switch to the rectifier. But Id still need to come up with some way to regulate it.