Controller coming on when battery disconnected

[appleseed123]

Ok, so I got a Lyen sensorless controller for my bike. My motor is a HS3540 with 3 12v SLA in series
The bike works awesomely. One thing thou that is weird, when i disconnect the ground to the battery the controller shuts off (all good, i use a key/switch on the ground wire for ignition), but if i go to bike again with the battery still disconnected the controller starts back up again from the electricity from the motor.

It only starts up again at about 10km/h , and below that it trys to turn on and off over and over.
I am not on the brake (regen works thou), and if i try to use regen nothing happens (with the battery disconnected).

When i am at a stop, the CA says -3 watts so maybe that has something to do about it?

Any idea? I dont want to wear out the controller by biking with using the battery.

 

[dnmun]

sounds like you have used the CA pcb ground trace to carry the motor current. hopefully it has not burned up yet.

 

[amberwolf]

I dont want to wear out the controller by biking with using the battery.

I don't think you're going to wear out the controller by using it normally. The battery, yes, but the controller should outlast the battery.

 

[appleseed123]

Still, i dont think that the controller turning on and off 50 times a minute when biking 10km/h is good for it. If not it then the CA.

 

[icecube57]

Ive experienced the same thing where the motor acts as a generator when no battery is plugged in. the CA comes on and displays speed and voltage after a certain speed. Seems like the MCU or ignition lead needs to be on a switch to prevent the controller from turning on.

 

[dnmun]

no, he has the switch in the ground. so the controller is getting power through the shunt connection to ground in the CA. it may be current limiting because the electronics in the CA are reversed somehow. i am surprised the CA still functions. figured he would burn it up doing this.

 

[appleseed123]

Thanks, i put a switch on the ignition wire and it worked. It no long comes on when biking (with the ground disconnected).

Also, thanks for the fast replies guys

 

[dogman dan]

Another simple fix, unplug the phase wires to the motor when you pedal unpowered. Then regen has no way to reach the controller. Some claim the motor resists less this way. I've never felt much difference myself though. Possibly that's because when I run out, I'm riding uphill to home every time.