EMTB power keeps cutting out an hour into my ride

kla456

Member
Mar 8, 2020
68
15
Scotland
@Steve b , you’ve described, almost, what happened to me. (Bosch gen4 2020 Rail 9.7, Kiox, 625w, similar mileage).
Motor cut out 20min into my ride, usually in the same spot (gravel access road). I could count on this happening, at this stretch of gravel road, almost every time. Not too steep, not rough, but not smooth either. The cut off did happen in another area, once, while I was passing another eMTB. Never on a decent or a rock garden climb.

When I would lose power assist, I usually peddled through it until power returned. If the Kiox completely lost power then I would have to stop my bike and restart the Kiox. To me this was a mystery. I had the latest update, motor was quiet, no weird rattle, wet-ish environment, rode almost daily for 15-25kms, full charge each time, (fresh underwear each time). I was searching for anything. Everything looked fine.

All the suggestions here are possibilities and this forum is where I finally found a solution. Poor battery connection. The fix suggested was to slightly reposition the battery connection plate (1mm maybe) by loosening the plate bolts and prying it slightly closer towards the battery. Retightened and checked for battery fit.
Problem solved. Never had a vibration frequency induced cutoff again. I’m not sure if I got lucky but I could have searched other possibilities first and eventually made it to the connector issue. (I also stopped searching for a buried Flux-Capacitor in that spot 😉).
I have the same issue as you with 2020 Bosch gen4, Kiox, 625w battery. Can we discuss separately, not taking space in this tread?
 

Steve b

Member
Apr 11, 2021
26
6
Peak District
25 mile muddy, hilly, rocky ride ride in the Peak District today and no power cut-outs.
1. Cleaned all the contact points thoroughly (again)
2. Judicious amount of dielectric grease behind the prongs that connect into the battery
3. Tightened up the battery in the bike
I can't believe the issue I was having was simply down to poor electrical contact, why did it happen 40 -60 minutes into the ride and not immediately... It's a mystery. I do remove the battery and charge it and store it indoors in the winter - perhaps increasing wear and misalignment of the contacts - who knows.
But nothing to do with batteries, controllers/displays, torque sensors, magnets etc. Electric bikes are a law unto themselves.
Thanks for all the suggestions and help from the forum members. Happy riding
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,283
4,780
Weymouth
By then, there's less voltage in the battery. Effectively, at some point, the voltage was less than was necessary to bridge the poor contact.

Glad to hear you're on the roll again ! Assisted .. for all of it ! :)
maybe...................or................current flow always finds the path of least resistance. The combination of a poor connection at the main connector possibly due to oxidisation or lack of a firm male to female connection, plus some moisture ingress at that connection plug created either a pos/neg short circuit or a short to earth.
Emtbs are not "a law unto themselves", they merely adhere to the rules for all electrical devices. Keep contacts clean and dry. now if you consider the environment that the bikes are used in, and the fact that even the major brands really have little idea how to protect the electrical circuits in their bikes, it means doing some mods and plenty of maintenance to keep it trouble free. If you have a cutaway downtube the main plug connector needs more protection than most bikes have as standard.
Pleased the OP sorted it..............now seal up that downtube!!
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,907
20,612
Brittany, France
or lack of a firm male to female connection
I've no idea why you're trying to bring @BAMBAMODA into this. It's a Mountain bike forum, not a place to spend our time trying to humiliate people just because of their ..

poor connection at the main connector

Needless to say, his lack of effort does generally lead to a lack of :

moisture ingress

He's there now fortunately :

Keep contacts clean and dry

But I believe he strongly disagrees with this system :

the main plug connector needs more protection

Please disregard this post in its entirety.
 

EuanHarris7

New Member
Jun 15, 2024
5
1
PerthShire
I have a Haibike All Mountain 7, 2 years old, approx 3000 miles. My ride starts OK, but after an hour or so I lose power suddenly and the controller turns off. I can then restart the controller but after about 3-4 minutes the power cuts out again. This continues to the end of the ride. It seems that once the power has cut off the first time I can't access anything greater than Standard/Sport assist (perhaps even Eco, hard to tell). I have cleaned the contacts points of the battery/pins with electrical cleaner and the battery is kept indoors. Any ideas - Thanks very much
Hi there, Just recently joined this form & I seem to be having the same problem your post is about? I’m just curious too see if you managed to resolve the problem you have and if so what did you do to get the bike to stop getting out?
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,283
4,780
Weymouth
Hi there, Just recently joined this form & I seem to be having the same problem your post is about? I’m just curious too see if you managed to resolve the problem you have and if so what did you do to get the bike to stop getting out?
what bike?
 

Tim S Realtor

New Member
Jun 19, 2024
1
0
Bristol, VA
I have a Haibike All Mountain 7, 2 years old, approx 3000 miles. My ride starts OK, but after an hour or so I lose power suddenly and the controller turns off. I can then restart the controller but after about 3-4 minutes the power cuts out again. This continues to the end of the ride. It seems that once the power has cut off the first time I can't access anything greater than Standard/Sport assist (perhaps even Eco, hard to tell). I have cleaned the contacts points of the battery/pins with electrical cleaner and the battery is kept indoors. Any ideas - Thanks very much
I had the same issue and the cure for mine was so simple. Check the rear wheel speed sensor. Ensure it is aligned correctly
 

kla456

Member
Mar 8, 2020
68
15
Scotland
Don’t know Yamaha. If you have a separate controller or app control of the motor, consider if the controller or app is closing down the motor. Consider controller battery, software updates, app settings. Try to run the bike static without external control. I had a similar problem with a Bosch system that immediately fixed by replacement of the Knox controller.
 

Ritchie66

New Member
Jul 1, 2024
4
0
Uk
I have a Haibike All Mountain 7, 2 years old, approx 3000 miles. My ride starts OK, but after an hour or so I lose power suddenly and the controller turns off. I can then restart the controller but after about 3-4 minutes the power cuts out again. This continues to the end of the ride. It seems that once the power has cut off the first time I can't access anything greater than Standard/Sport assist (perhaps even Eco, hard to tell). I have cleaned the contacts points of the battery/pins with electrical cleaner and the battery is kept indoors. Any ideas - Thanks very much
Hi Steve ,
i‘m new to the forum, I have virtually the same issue as you.
my Haibike has the Yamaha pwx2 motor. I’m on holiday at the moment so limited to what I can do.
Did you resolve your problem, if so how?
any suggestions please
 

EuanHarris7

New Member
Jun 15, 2024
5
1
PerthShire
Hi Steve ,
i‘m new to the forum, I have virtually the same issue as you.
my Haibike has the Yamaha pwx2 motor. I’m on holiday at the moment so limited to what I can do.
Did you resolve your problem, if so how?
any suggestions please
Hi there, I’ve also the same issue. Did you manage to resolve the problem?
 

Ritchie66

New Member
Jul 1, 2024
4
0
Uk
Hi there, I’ve also the same issue. Did you manage to resolve the problem?
Hi Euan, not yet!
I was also getting error 73. I’m away on holiday , so will carry out more connections checks around the motor leads soon.
Battery levels check ok, my feeling is electronics in the motor , but not diagnosed yet.
Any other ideas would be grateful.
 

EuanHarris7

New Member
Jun 15, 2024
5
1
PerthShire
I done the diagnosis test threw the controller pad and it passed all the tests, I never got any error codes coming up & I never had any error codes in the error history list. Out of curiosity which Mode/Assist do you cycle in the most when you are out cycling?
 

Ritchie66

New Member
Jul 1, 2024
4
0
Uk
I done the diagnosis test threw the controller pad and it passed all the tests, I never got any error codes coming up & I never had any error codes in the error history list. Out of curiosity which Mode/Assist do you cycle in the most when you are out cycling?
Hi
Mainly std, then eco , then occasionally high
 

Plummet

Flash Git
Mar 16, 2023
1,084
1,538
New Zealand
I've got a similar problem with my 23 bosch smart system. They replaced the battery in the remote, I don't have a display, but still got a shuddering typing cutting out after at hour or so riding.

I've contact cleaners the contacts. Will try a bit more cleaning and maybe the dielectric grease idea.

Ps the cutting out happens more so on when rides after an hour or two of riding.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,283
4,780
Weymouth
I've got a similar problem with my 23 bosch smart system. They replaced the battery in the remote, I don't have a display, but still got a shuddering typing cutting out after at hour or so riding.

I've contact cleaners the contacts. Will try a bit more cleaning and maybe the dielectric grease idea.

Ps the cutting out happens more so on when rides after an hour or two of riding.
If your bike uses the LED Remote controller be aware that it uses a 3.7v rechargeable battery .....charged by the main battery when the system is switched on. The LED Remote battery has a 3 wire connection. Pos, neg, and control. The control wire is connected to a thermistor within the battery pack and a diode (probably) on the LED Remote printed circuit board. .......to prevent overcharging. If that set up goes faulty the battery does not get charged and the LED Remote shuts down. The solution is a replacement LED Remote. That may be your issue.
 

Plummet

Flash Git
Mar 16, 2023
1,084
1,538
New Zealand
If your bike uses the LED Remote controller be aware that it uses a 3.7v rechargeable battery .....charged by the main battery when the system is switched on. The LED Remote battery has a 3 wire connection. Pos, neg, and control. The control wire is connected to a thermistor within the battery pack and a diode (probably) on the LED Remote printed circuit board. .......to prevent overcharging. If that set up goes faulty the battery does not get charged and the LED Remote shuts down. The solution is a replacement LED Remote. That may be your issue.
I have the wireless remote.

I co cleaned and did a mild scuff on the battery connector male spade terminals. It didn't fault yesterday with a full battery burn.
Next step will be dielectric grease the outer connector to keep moisture out.
 

Ritchie66

New Member
Jul 1, 2024
4
0
Uk
Hi Euan, not yet!
I was also getting error 73. I’m away on holiday , so will carry out more connections checks around the motor leads soon.
Battery levels check ok, my feeling is electronics in the motor , but not diagnosed yet.
Any other ideas would be grateful.
Just an update on my errors 71 and 73
The motor is being repaired due to water ingress on the PCB and electronics . Cost is £370 for pcb and 2 crank bearings , 🤞🏻I’ll be back on the trails soon
 

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