Controller for Bafang FM G311.250.D 13

[zynaps2k1]

Hello!

I am new in this forum and i have been searching info of a Bafang controller compatible with a Bafang FM G311.250.D 13 with no success.

This is the Bafang motor i have:

i would like to use this motor with a 48V battery on a Xiaomi Qicycle EF1 modified with 20" wheels. In the sticker states that this motor is for "big" wheels, so i dont't know if it will works correctly.

I have the motor and a 48V battery, so i suppose that i need the controller, pas sensor and display, but the more threads I read, the more doubts I have about RPMs for small wheels, phases, watts...

Any help would be greatly apreciated.

Thanks in advance!

 

[zynaps2k1]

Of course If it were better to buy a complete motor kit (hub motor, controller, pas sensor etc) i would try to find it.

More info about the bicycle in case it helps:

Xiaomi Qicycle EF1. Its working with its original motor, 250 W, 36 V high-speed motor M108RL from Ananda. Originally their specs where:

2 coils on the outer ring make the 10 magnets on the center spindle go round and round–260 times per minute. The motor has a continuous output power of 180W and 7.3 Nm of torque. (Ifixit Xiaomi MiJia QiCycle Folding Electric Bike Teardown)

Oficial Ananda specs

But with its controller modded to feed 48V to the motor hub, so the bicycle now can go at 32/34km/h on flat ground and pedaling comfortably.
The controller:


Again thanks in advance.

 

[gromike]

Should be easy to find a controller kit that fits your bafang motor as plug 'n play. KT is kind of the go to for a motor like that.
If the motor is a standard wind you won't go as fast as with a fast wind. Be good for hills, though.

 

[zynaps2k1]

Thank you for your quick answer!

So a kit like this with KT controller should be compatible:

https://es.aliexpress.com/item/1005004058514773.html?spm=a2g0o.cart.0.0.4af87a9do1fq3T&mp=1&gatewayAdapt=glo2esp

If the motor is a standard wind you won't go as fast as with a fast wind. Be good for hills, though.

Thanks for the info, i will update thread with the results.

 

[docw009]

How did you get 20" wheels into a 16" bicycle?

Motors are designed with a target RPM at a given voltage. The G11 appears to come in a 200 and a 310 rpm version., WIth a 20" wheel, I estimate 200 rpm is 19 km/hr and 310 rpm is 30km/hr. I think the Xiaomi Qicycle EF1 had a 260 rpm motor for 19 km/hour on 16" wheels,

All of this is simple math. With 48V, I would guess there's about a 20% increase. That's my experience when I've gone from 36V to 48V on the same bikes.

KT controllers should connect right up with a bafang motor. You might look at a 20A model. Avoid the simpler displays that don't allow use of the many options on the controller.

 

[zynaps2k1]

How did you get 20" wheels into a 16" bicycle?

The rear wheel was easy, there was enough space only had to modify the anchor points of the mudguard.

Ther front wheel was harder. I had to change the fork and the mudguard. The new fork had disc brake mount, so I adapt the hub to use disc brakes.

This is the "evolution":
16"-16"


16"-20"


20"-20"

Motors are designed with a target RPM at a given voltage. The G11 appears to come in a 200 and a 310 rpm version., WIth a 20" wheel, I estimate 200 rpm is 19 km/hr and 310 rpm is 30km/hr. I think the Xiaomi Qicycle EF1 had a 260 rpm motor for 19 km/hour on 16" wheels,

All of this is simple math. With 48V, I would guess there's about a 20% increase. That's my experience when I've gone from 36V to 48V on the same bikes.

I apreciate this info a lot, thank you very much! Unfortunately i think that my G11 is de 200rpm version (13t), so with 48v i think that my top speed will be a little less than 25km/h. If I feel the bicycle too slow, I will look for another motor with more rpm in the future.

KT controllers should connect right up with a bafang motor. You might look at a 20A model. Avoid the simpler displays that don't allow use of the many options on the controller.

Perfect! the KT controller have 22A. The included display its very small, I will look for another more advanced display.

Thank you very much!