Bafang motor question.

[Hixyhicks]

If i turn off the motor peddling is really hardwork.I was going down hill and it feels like im peddling up hill on a normal bike.Once i engage pas 1 the bike is then ok.Im trying to save battery.Is this normal for a bafang motor ?

 

[Benjahmin]

No it's not. Are all your brakes adjusted properly, i.e. not binding? Is it a front or rear motor, is it fitted so that it clears frame and forks, does it rotate freely when hand spun on the stand with no power?
You can save battery any time by slightly pulling a brake which has a switch which disengages power supply to the motor.

 

[Hixyhicks]

All of those things are fine,maybe its just the weight of me and they bike,I removed the brake sensors because they both stopped working and i haven't replaced them.

 

[Andy-Mat]

All of those things are fine,maybe its just the weight of me and they bike,I removed the brake sensors because they both stopped working and i haven't replaced them.

It might be fun to place a switch somewhere that simulates the brake sensor(s), easily accessed while riding, and see if operating the switch, frees up the motor, as someone mentioned here.
If it does free the motor, then you will know its possibly some sort of a motor/controller control problem.
I would guess that it is, and its called dynamic braking, at least when its wanted, but its not wanted in this case!
It can even be caused by a motor MOSFET shorting for some reason, or being switched on at the wrong time by the controller for some (other) reason, then operating the brake sensor switch will probably not fix the problem.
If you wish to understand more, he is a good place to start:-

Dynamic braking - Wikipedia

en.wikipedia.org

 

[Hixyhicks]

I hope theres not a problem its virtually new.I will buy a brake sensors and see if that helps.The reason i havent replaced them is because there crap.Is there an after market sensor i can buy instead of the cheap bafang versions?

 

[WheezyRider]

If i turn off the motor peddling is really hardwork.I was going down hill and it feels like im peddling up hill on a normal bike.Once i engage pas 1 the bike is then ok.Im trying to save battery.Is this normal for a bafang motor ?

It may be that the clutch is not disengaging. Turn the bike upside down, turn the rear wheel by hand in the direction of normal rotation. It should spin freely and rotate several times with a simple hand push before coming to a stop. Then try rotating the wheel in the opposite direction. The clutch should now engage and it should be more difficult to turn the wheel as you are now turning the motor as well as the wheel.

Don't spend any money on brake sensors or whatever until you have eliminated the basics. You can also disconnect the motor from the controller when you do the test above to eliminate any potential "dynamic braking".

 

[Nealh]

Don't switch off going downhill simply leave the system on an set the assist to zero.
The bike should pedal down hill with ease.
Test the wheel for rotation at home with the system off, the wheel should freely rotate when spun by hand.

 

[Hixyhicks]

WheezyRider,just did that and it works as it should.Maybe because the motor is doing what it should so well that when its not engaged im really feeling it.Im 17 stone the bike cant be far of 30 kg .The crank arms spin freely through the bottom bracket.Maybe there isnt a problem im just fat and unfit.

 

[WheezyRider]

WheezyRider,just did that and it works as it should.Maybe because the motor is doing what it should so well that when its not engaged im really feeling it.Im 17 stone the bike cant be far of 30 kg .The crank arms spin freely through the bottom bracket.Maybe there isnt a problem im just fat and unfit.

Ok, check your front brakes next, are they dragging? What are your tyre pressures like?

 

[vfr400]

I think you need to tell us whether you have a crank motor or hub motor.

 

[Nealh]

Yes as always vfr has his thinking head on, if a crank drive then the internal gearing is horrible and they take serious effort to ride unpowered. I tried to this with my one about 5 years ago and the effort needed wasn't great so generally went back to hub drive.

 

[Hixyhicks]

The brakes are fine. They dont drag,ive just replaced the pads on the front,they dont last long.The motor is a Bafang HD.

 

[vfr400]

Put the bike in bottom gear, then turn it upside down (switched off. Spin each wheel by hand to check that they spin freely, then turn the pedals by hand. You shouldn't be able to feel the motor turning and the pedals should require very little effort to turn.