Motor suggestion

Converting a Coleman mini bike to electric. I installed a Kun Ray 2000w motor and controller combo from Amazon. It works, but only on the flats. Any hills and the motor doesn’t have enough torque to move the bike and the controller overheats. Also, motor runs rough at lower speeds. I did have to swap the phase wires to reverse the rotation of the motor. It does have good top speed though. I haven’t measured but feels like about 25-30 mph.

Looking for a motor and controller recommendation. I have two 48v 35amph batteries that put out 50amp continuous and 100amp peak. If need I can combine them to get 98v, but would prefer not to. Needs to tackle hills and decent top speed.

Any help is appreciated.

My setup now.

Do you want a hub motor or go with the Unite Motor thats already installed?

For the motor you already have - You can change the sprockets and get better gearing for the hills which will slow down your top speed.

If you want a new motor, the same kind you already have then look at Unite Motors, I have no idea nor can I find off hand the various model numbers corresponding to wattage output. Gearing is your best bet though to start off with :thumb:

For hub motors the key points to know what is the rear dropout width, then that can determine the motor.
Your pictures, the dropouts look super wide, probably larger then a fat bike hub motor.

Scooter motors are available, these look like 190mm
https://www.qsmotor.com/product/10inch-3000w-hub-motor/

Controller for the hub motor is any brushless, and I'd go with sensorless which I buy from EVfitting Greentime on Aliexpress.
https://evfittinggreentime.aliexpress.com/store/313864

rock_rattt said:

Converting a Coleman mini bike to electric. I installed a Kun Ray 2000w motor and controller combo from Amazon. It works, but only on the flats. Any hills and the motor doesn’t have enough torque to move the bike and the controller overheats. Also, motor runs rough at lower speeds. I did have to swap the phase wires to reverse the rotation of the motor. It does have good top speed though. I haven’t measured but feels like about 25-30 mph.

Click to expand...

Rough running and hot controller and insufficient power sounds like you have a false positive hall combination. If you only swapped phase wires and did not also swap halls as needed to match (not usually color for color), and it started out as a working good combination, then it has probably created a false-positive combination.

Since you already know the working forward phase combo, try swapping the three hall signals (not 5v and ground) around until it is still a forward working combo but the problems go away. If it doesnt' work with that phase combo for some reason you can note that and try another, then reorder the halls until you find one that works correctly.


The other potential issue is gearing. Sometimes you have to trade torque for speed, so you might need to change the gearing ratio to get a lower top speed to get the hill climbing torque you need.

Alternately, you may simply need a much bigger controller and motor, but that seems unlikely--if it literally can't move the bike except on flat ground at 2kw, then you'd probably need several times that to climb anything significantly steep, which isn't typically the case. You can use the ebikes.ca grin tech motor simulator to help figure out what kind of system power should be needed for a particular use case.

(I used to be able to ride CrazyBike2 up Cave Creek Road from 7th all the way to the other end of the hill and back, here in Phoenix, which you can lookup the grade for on google maps, with only 4kw of power and not using nearly all of that, even though the bike and I and stuff on it were over 400lbs (probably more like 450+), at 20mph the whole way, and probably could've gone faster if it were legal--and that's just with 2wd DD hubs, not a chaindrive where the motor can be kept closer to it's efficient RPM. )

[/quote]
Rough running and hot controller and insufficient power sounds like you have a false positive hall combination. If you only swapped phase wires and did not also swap halls as needed to match (not usually color for color), and it started out as a working good combination, then it has probably created a false-positive combination.

Since you already know the working forward phase combo, try swapping the three hall signals (not 5v and ground) around until it is still a forward working combo but the problems go away. If it doesnt' work with that phase combo for some reason you can note that and try another, then reorder the halls until you find one that works correctly.


The other potential issue is gearing. Sometimes you have to trade torque for speed, so you might need to change the gearing ratio to get a lower top speed to get the hill climbing torque you need.
[/quote]

I swapped both the phase and hall wires. I did green to green and blue to yellow. It starts rough but ends up smooth at higher speeds.

I’ll give the gearing a try. I do hav have a 72 tooth in the back. But even on the flats it’s slow to start, not very good acceleration.

Thanks for the suggestion Markz. I was looking at QS motors after I posted.

rock_rattt said:

I swapped both the phase and hall wires. I did green to green and blue to yellow. It starts rough but ends up smooth at higher speeds.

Click to expand...

When you swap one color pair on the phases, it's fairly common for the halls to need a different pair to be swapped, so if you have not yet experimented with other phase/hall combos, I highly recommend doing this. A false positive combo really is the most common cause for what you are seeing.