KU63 KU93 KU123 controller hacking

[casainho]

Hello.

Recently I bought a BMSBattery KU123 controller for a Bafang 48V 500W motor. I didn't used torque arms and I just had 30 seconds the bicycle with me and after the aluminium dropouts on the forque broke!!

Sure that the dropouts broke due to no using of torque arms but also the KU123 controller delivers 30A (~1500W) to the motor which is a LOT!! I need a controller that delivers no more than 350W, it's my target since I want to always pedal and I used a 250W motor but I need just more 100W to win against the wind.

My question is: does anyone knows how can I hack this kind of controllers, to provide less Amps/power and a ramp of power, not almost instant power??

I know I can smooth the throttle to get a ramp of throttle acceleration however I would prefer the controller did that, like in case a jump in a bump and the motor will quick accelerate and provide high power to the wheel, make it dangerous.

[Riche]

I dont know about any hacks for the KU123 but a Cycle analyst might be able to limit the current for you . I have the same motor/controller and my cycle analyst reconds I am burning up to 1.8kw (38A) up steep hills..

Rich

[miuan]

Open it up and cut one of the dual shunts. They are dual silver conductors near the edge of the board, opposite the wire exit. If the power is still too much, grind the remaining shunt thinner or put the second shunt in series with it, so you effectively get near 10A down from 40A. I believe 15-20A is what you're after anyway.

[Russell]

Miuan's suggestion is a good one, just snip one of the shunt wires (assuming there are 2). It's a waste though running around with a 12-FET controller putting out a say 15A.

I played with the shunt on a 9-FET controller (it only had one) by adding/subtracting solder to it and could "tune" it anywhere between 13 and 27A. At 13A and 12S LiPo (~600Wp) the "250W" motor felt noticeably weaker than at 19A previously but it was OK for assist.

Really though you did buy the wrong kit if all you want is a little assist. The Bafang BPM (shown in your link) is much more powerful than the smaller 250W Bafangs, like the one I use. When you buy a little Bafang kit they include a little controller to go with it.

Second, you ignored all the warnings about using a front motor on aluminum forks, especailly a powerful one. I run a little "250W" Bafang with a 20A controller with a 12S LiPo battery which peaks at around 950W and don't have a problem even without a torque arm...but I have steel forks.

So yeah you can de-rate the set-up you have or sell the kit and buy a lighter less powerful one.

-R

[d8veh]

Just use the KU93. You'll find it perfect for what you want.

[casainho]

Miuan's suggestion is a good one, just snip one of the shunt wires (assuming there are 2). It's a waste though running around with a 12-FET controller putting out a say 15A.

If there was an OpenSource hardware and firmware controller... I would buy one instead.

Really though you did buy the wrong kit if all you want is a little assist. The Bafang BPM (shown in your link) is much more powerful than the smaller 250W Bafangs, like the one I use. When you buy a little Bafang kit they include a little controller to go with it.

Maybe I do not want a little assist but a moderate assist. Maybe I will find I am better with an electric motorcycle...
I came from a 250W Cute-85 motor that runs at maximum 38km/h. Now I would like to go up to 44km/h and so maybe I need more 100W (also for wind days), so, 350W. That Bafang BPM seems to be the best that BMSBattery have for what I am looking for.

Second, you ignored all the warnings about using a front motor on aluminum forks, especailly a powerful one. I run a little "250W" Bafang with a 20A controller with a 12S LiPo battery which peaks at around 950W and don't have a problem even without a torque arm...but I have steel forks.

I totally ignored the existence of torque arms and the reason for their existence. BMSBattery didn't sell them before my accident. I came from a 180W motor and after from the Cute-85 250W motor, all of the material I bough on BMSBattery on 2 years ago, 1 year ago and now few weeks ago. I always used the same bicycle with all this motors.

So yeah you can de-rate the set-up you have or sell the kit and buy a lighter less powerful one.

I think I will de-rate. I bought now from BMSBattery the torque arms and KU93 controller. I am not really sure but later I can even change from the Bafang 500W front to rear motor.

I were doing with the Cute-85 250W motor 25km + 25km with a battery charge/day. Now I would like to do the same and sometimes even go behond to 33km + 33km, that's why I am looking to a bit more power/speed.

[h0tr0d]

DIY Controller:

viewtopic.php?f=30&t=23350

Cumprimentos!