Help! Intermittent power stop/start on 'High' mode

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Hiya, I'm hoping someone can help me with some technical advice. I've a Decathlon Bebike 700 that has started playing up.
The cycle assist seems to stop working especially on 'high' mode. As I click on H the you can feel the motor delivering power but it's only for about a second and then clicks off. All the lights on the panel stay illuminated when this happens. Any ideas folks? I've played around with the pedal assist sensor but this does not seem to affect it. Thanks
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,847
1,728
Basildon
If the lights stay on, it's not the battery, its connections, switch or fuse. If it only does it on high power setting, that eliminates causes to do with the control system unless there's an over-sensitive temperature sensor somewhere. Logically, the cause is somewhere between the controller and the motor, most likely the motor connectors. Check that the one near the motor is all the way in to the marked line.
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Ah okay, I'll look into that, it's strange that it only happens on High mode. Thanks for the input, I'll post my findings within the next day or two. Cheers
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
11,138
4,296
57
West Sx RH
The cutting out in High mode may suggests more current is asked for and this current can't be sustained by the battery, it may be that the battery has an issue.
How old is the bike ?
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
The bike was bought new in 2015 and is still literally new, I'd say it's had less than 20hrs of use.
How would I test the battery ??
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Just some feedback on the issue I'm still having.
I sent the battery off for a thorough test as I though there could be a cell or two breaking down under load.
The BMS was replaced all the cells checked and found to be good. I received the battery back yesterday. Well I fitted the battery and went for a quick ride only to find that the problem is still there! I was gutted... It doesn't cut out in Low only on High and sometimes M.
Could the controller be at fault?
Any suggestions would be helpful please.
Sven
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,847
1,728
Basildon
I told you above that there's nothing wrong with your battery. If there was, you'd see the battery indicator lights go out when the motor cuts. It's most likely a faulty connection on the motor cable. Check everything between the controller and the motor, especially the one next to the motor, which must be all the way in to the line if you have the standard 9-pin connector.
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Thanks for the reply....I'll give all the connections another check this weekend.
I do hope it's something that simple as the bike is pretty much useless in the state it's in.
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Well, still no progress with the issue on High mode. All connectors have been checked and have all been checked and pushed all the way in.
What I have tried is putting the bike on my turbo trainer and spun the pedals in all 3 power modes and it works! Unfortunately as soon as start applying resistance I loose power in H but the other 2 modes seem to cope okay?
I'm starting to think that it is possibly the controller.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,847
1,728
Basildon
There isn't really anything in the controller that can do that unless it's some sort of unusual fault. Can you just clarify what's going on?

I understand what you're saying about the motor cutting, but what happens after that? How does it come back on to try again? Does it come back by itself or do you reset something?
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Hi again vfr400, thanks again for your input. I had done a short video showing the problem. As you can see if you click on the link, when the power clicks off (as soon as H mode is engagaed) and i toggle back to L and M and H the power does not come back on automatically ( I am still pedalling by the way) What I have to do is back pedal for a second or so and then the power will resume on L, M etc. Hope this explanation is okay, cheers.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,847
1,728
Basildon
OK, try this: Just leave it on level 3 and keep pedalling. Will it eventually cut back in and out again if you leave it long enough?

With the wheel off the ground, there's no load, so it must be a speed related issue. it looks like the 15 mph cut-off has cut the power, but is taking a long time to reset.

When you're on the road and start off on level 3, how long before it cuts out? Does it do it immediately, like in the video?
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
Hi.....no it won't kick back in if I keep on pedaling even if i keep it up for a good 15 seconds. All 3 speeds work fine when there is no load and the back wheel is spinning freely.
If i'm on the road and try set off on level 3 it will click off immediately. What I have to do then is knock in down to M or L but for this to happen I need to backpedal for a second, which seems bizzare. It's as if it resets when I do this. If I don't backpedal after it clicks off, M or L will not power back on??? Its a bloody mystery.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
4,847
1,728
Basildon
Hi.....no it won't kick back in if I keep on pedaling even if i keep it up for a good 15 seconds. All 3 speeds work fine when there is no load and the back wheel is spinning freely.
If i'm on the road and try set off on level 3 it will click off immediately. What I have to do then is knock in down to M or L but for this to happen I need to backpedal for a second, which seems bizzare. It's as if it resets when I do this. If I don't backpedal after it clicks off, M or L will not power back on??? Its a bloody mystery.
yes, it is a mystery. I've not seen anything quite like that before. It's like something has gone wrong in the controller logic.

There is one thing I can think of, and that's water in the control panel or some other damage. Maybe level 3 is damaged in some way and giving out too high a voltage, which the controller is rejecting and shutting down.. Some of those panels can be opened after removing screws, others are glued together. If your has screws, it would be worth looking inside.
 

svenski

Finding my (electric) wheels
Jun 21, 2020
11
1
I looked at the control panel yesterday and unfortunately its well and truly shut tight. No way of getting in. They also don't have stock of these at Decathalon. I've been told they're on back order. They're only £22 so worth a punt. Decathalon N.Ireland and Spain do but won't post out of their countries!
There are similar looking ones online but the connectors on the Decathalon stuff (well this one) seem to be a hulong type and not very common.
In the meantime I will just have to accept that the bike will only work in L and M now which can be quite limiting.
Thanks for all your help VFR400, it's greatly appreciated.
 

Advertisers