Bafang Rear Hub Motor Questions

[saneagle]

Hope this helps

It looks like it might be code 9, which is 340 rpm at 36v. That would make it a bit fast for 48v. The only way to be sure is to see how fast it goes on the speed display.

 

[saneagle]

Also, if it is G010 or G020 makes quite a difference. The G010 has a lot less torque.

Motors don't have torque. Instead, they give torque that depends on the current and voltage. Maximum current depends on the controller, and it varies in accordance with speed. When manufacturers mention torque, it's meaningless unless they say the conditions under which they measured it, which are speed, current and voltage.

In any DC motor at any fixed voltage, torque is more or less proportional to current, provided that the current is in a suitable range for the motor.

 

[manman94]

Yes thanks but I'm still waiting for the answer what is the maximum power controller I can use with my 250w 36v motor rear geared hub I have at this moment a KT 36v48v 17a controller installed could I go higher or is the limit for my set up.

 

[AGS]

What is the maximum current that your battery can safely deliver?

You need to consider all three things, motor, controller and battery, otherwise something is going to break.

 

[manman94]

My batteries are 36v 21ah and 48v 21ah if that helps

 

[Peter.Bridge]

What size wheel ?

 

[manman94]

20 inch

 

[AGS]

My batteries are 36v 21ah and 48v 21ah if that helps

You need to know the maximum current the battery can deliver. If you fit a bigger controller that takes a higher current than the battery can deliver you will ruin the battery.

Your motor is easily capable of 1000 watts, but only if the other components are rated high enough.

You can use the Grin motor simulator if you spend a bit of time learning how to use it. It has a G062 as one of the motors, so you can simulate various settings to see how it performs. In my experience it is very accurate.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

 

[AGS]

Here is an example for your motor using a 20 amp controller.

You can adjust the settings to see how far you can take it before the motor overheats. Put the overall wheel diameter in which includes the tyre. Don’t use the rim size.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

 

[manman94]

To confusing for me I'm afraid but thanks I just thought it was a simple question of what maximum power controller I could use or should avoid before hitting problems.

 

[AGS]

Why don’t you ask Jimmy at Insat what the maximum current that you battery can deliver?

Then you will know the biggest controller you can fit.

And then you can plug that information into the Grin simulator to see how well your motor will perform.

 

[saneagle]

20 inch

That changes things. 340 rpm is OK for 48v. I think 17A would be a happy maximum. I can't think of any circumstances where you'd want more power than that with 20" wheels.

 

[Peter.Bridge]

The G062 controllers on eBay, Amazon and AliExpress are all 30 amps. That sort of makes sense, my G020 hub motor, which is much lighter duty, came with an 18 amp controller

Whether you need that much power is another question - I changed my controller to 48V 15A max and a bottom bracket torque sensor and that lets me get up all the steep hills round here (which are up to 1 in 4)

I suspect your battery might be the limiting factor, what is the max continuous (not peak) current ? I think, to be safe, people have recommended that it should be 5 amps greater than the controller

 

[WheezyRider]

Motors don't have torque. Instead, they give torque that depends on the current and voltage. Maximum current depends on the controller, and it varies in accordance with speed. When manufacturers mention torque, it's meaningless unless they say the conditions under which they measured it, which are speed, current and voltage.

In any DC motor at any fixed voltage, torque is more or less proportional to current, provided that the current is in a suitable range for the motor.

Yes, it's all a bit hand waving. Just whatever measure the company uses, the result is lower for the G010 than the G020 and the difference is noticeable in the real world.

 

[WheezyRider]

20A at 48V should be plenty. You could go higher, but then you start straining the battery unless it is very big.

 

[manman94]

Thanks for all the advice guys ,I have now fitted a 17a 36v48v KT CONTROLLER it's great at pedal assist 4 and 5 but heavy on 123.
I do have a KT CONTROLLER 36v48v 20a also I used that for a while but noticed at pedal assist 5 it was really jerky I guess it wanted to go faster,but unfortunately here in the Netherlands 25km is the maximum.although with the 17a controller I know I can get more speed at pedal assist 5 but it's not jerky when it hits 28km though I'm a couple of km over the limit here in the Netherlands the police will allow 3km margins.