EBike not running / controller issues (?) - advice sought.

RustBuster

Finding my (electric) wheels
Apr 18, 2022
11
0
Hello all

I'm not sure if this part of the forum is the correct place to place this post, having just joined, anyway, here goes:

I am trying to fix my sister-in-law's electric bike, it has stopped working, in that the throttle produces no effect, and neither does pedalling it (i.e. neither method invokes the motor).

Hazel uses the bike to get to work, and is missing it greatly.

We had a bike technician look at it, he is familiar with electric bikes, and unfortunately he said that as he didn't recognise the make or the components, he didn't have any means of testing it, though he did try the old disconnect the brake interrupter leads and see if that helps. The motor is brushless, its a 36V battery, I think its 250W . It has a hand throttle and a pedal-inducer, the motor is on the back wheel. The bike came from "Biycles4U", (and its badged as such), who have gone out of business. Its about 4 years old.

It seems to me that given that both the hand throttle and the pedal inducer are not working, it's a reasonable bet that the problem is in the motor, or in the controller, but that's just my best guess of course.

After a struggle I have got the controller out (it was held in a little aluminium cup below the bottom end of of the battery, the battery being on the down tube). It was sort of glued in there with silicon.

Anyway ,its out now, and its basically an oval circuit board. There are 6 wires going up to the hand throttle (two for the switch, on for the led display, and 3 for the HE thing). There are three wires going to the sensors ring thing which sits behind the chain wheel.

I have been testing things with a multimeter, and what i have found is that the battery appears to be fine, and the current is getting into the circuit board ok, and up to the hand throttle (the LEDs light up, the switch works). I took the hand throttle to bits to check it , nothing obviously wrong in there. Unfortunately as it has a pin connector joint on the end of the throttle cable, its hard to get probes/ crocodile clips onto the terminals to conduct a test, i.e. put 5 volts up there and see what comes down the third wire, but what did was measure the wires coming from the HE sensor where they were soldered to the circuit board of the controller, and got my wife to twist the throttle, and I could see that the voltage was changing as she twisted the throttle, so it seems to me that the throttle is working , at least partially anyway. I also got her to try the brakes, and I could see that the voltage was changing as she applied the brakes, so I'm guessing that the brake interrupters are not the issue. I have checked the power cables to the motor for continuity.

I have been measuring the AC voltage on the 3 terminals that supply the current to the motor, when the throttle is twisted, there's nothing there, at least , with the multimeter set to the 200 volts range (the options on the multimeter are 20v or 200v ). So it looks to me that everything that I have found so far points towards the controller being faulty - but my tests may be invalid - I don't pretend to be an electronics expert. Would anyone care to advise as to the validity of my tests ? Also, from a quick search on the internet, it seems that controllers are available for not too much money (i.e. £20 and upwards) - but as usual, there is a large range - so if I were to buy one, what would the best choice ?

Thanks in advance

RustBuster.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
19,991
8,173
60
West Sx RH
One can probe the back of the wire connectors if they are the small block type jst connectors, for throttle one should see 4.5 - 5v between gnd & 5v and about 1v between Gnd & sig when the throttle is operated, like wise with the pedal sensor should see the voltage switch as the magnets pass the sensor when probing gnd & sig wire. If that is the case then either controller mosfet/s are toast or possibly motor hall/s are toast.

Firstly do check the hub motor connector hasn't been dislodged or tampered with, make sure with firm push together it is fully home.

Any failure form one of these tests can prevent a motor from running.
Mosfet test.

Motor hall test.
HallSensorTesting.cdr (ebikes.ca)
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
19,991
8,173
60
West Sx RH
It is best to test and fault the reason before willy nilly swapping stuff out.
 

RustBuster

Finding my (electric) wheels
Apr 18, 2022
11
0
One can probe the back of the wire connectors if they are the small block type jst connectors, for throttle one should see 4.5 - 5v between gnd & 5v and about 1v between Gnd & sig when the throttle is operated, like wise with the pedal sensor should see the voltage switch as the magnets pass the sensor when probing gnd & sig wire. If that is the case then either controller mosfet/s are toast or possibly motor hall/s are toast.

Firstly do check the hub motor connector hasn't been dislodged or tampered with, make sure with firm push together it is fully home.

Any failure form one of these tests can prevent a motor from running.
Mosfet test.

Motor hall test.
HallSensorTesting.cdr (ebikes.ca)
Hello Neal, thanks for that. Unfortunately the connectors are not the JST, or even Deans or XT60, but are little tiddly circular cross-sectioned things, with tiny circular pins, the connectors are possibly bespoke / proprietary, I wouldn't know, they are about 6mm or so diameter (O/D) (well, that's the throttle and the two brake leads, the lead to the motor is a bigger diameter plug, but still not easily accessible, it is probably about 12mm diameter, but with a lot more pins in it).

Anyway, I have had a quick gander at the links that you have provided, and will hopefully give the techniques a try out tomorrow. I have also been searching the internet etc, to assist with my general knowledge of electric bikes. One thing that did occur to me is that, with the return wire from the throttle (the Hall Sensor), where I now have access to the controller's circuit board, but access to the throttle cable connector is very difficult due to the plug size as described above, what I could do is, short the connection where the Hall Sensor wire is soldered to the board, i.e. provide a direct link from the battery , including some resistors of course, so that the voltage is appropriate (like you say, somewhere in the region of 1volt plus), which would have the effect of emulating a signal from the throttle, then I would know for sure that the throttle efficacy is out of the loop, and if following that, the motor is energised, or at least, if a voltage can be detected on the 3 wires taking the power to the motor, we would then know that the controller is ok etc. An even more sophisticated approach would be to include a potentiometer in that temporary circuit, so that the voltage to the place on the circuit board where the Hall Sensor return wire joins may be varied (i.e. as if manipulating the throttle),
 

RustBuster

Finding my (electric) wheels
Apr 18, 2022
11
0
Hello Neal, thanks for that. Unfortunately the connectors are not the JST, or even Deans or XT60, but are little tiddly circular cross-sectioned things, with tiny circular pins, the connectors are possibly bespoke / proprietary, I wouldn't know, they are about 6mm or so diameter (O/D) (well, that's the throttle and the two brake leads, the lead to the motor is a bigger diameter plug, but still not easily accessible, it is probably about 12mm diameter, but with a lot more pins in it).

Anyway, I have had a quick gander at the links that you have provided, and will hopefully give the techniques a try out tomorrow. I have also been searching the internet etc, to assist with my general knowledge of electric bikes. One thing that did occur to me is that, with the return wire from the throttle (the Hall Sensor), where I now have access to the controller's circuit board, but access to the throttle cable connector is very difficult due to the plug size as described above, what I could do is, short the connection where the Hall Sensor wire is soldered to the board, i.e. provide a direct link from the battery , including some resistors of course, so that the voltage is appropriate (like you say, somewhere in the region of 1volt plus), which would have the effect of emulating a signal from the throttle, then I would know for sure that the throttle efficacy is out of the loop, and if following that, the motor is energised, or at least, if a voltage can be detected on the 3 wires taking the power to the motor, we would then know that the controller is ok etc. An even more sophisticated approach would be to include a potentiometer in that temporary circuit, so that the voltage to the place on the circuit board where the Hall Sensor return wire joins may be varied (i.e. as if manipulating the throttle),

Hello all.

The testing so far (i obtained one of the dedicated ebike tester devices) point to the controller being the problem. So, where is the best place for me to obtain a brushless controller for a hall-controlled 36v 250w installation ?

Thanks
 

RustBuster

Finding my (electric) wheels
Apr 18, 2022
11
0
Hello all.

The testing so far (i obtained one of the dedicated ebike tester devices) point to the controller being the problem. So, where is the best place for me to obtain a brushless controller for a hall-controlled 36v 250w installation ?

Thanks
Oh I forgot to add, i'm a bit puzzled about whether I need a square wave controller, a sine wave controller, or whether either would suffice ?