Diminishing returns ( bosch loses power )

[Gringo]

Now I'm paranoid, is this a warning sign of troubles to come or just a one off glitch.

I've been the happy owner of a cube 29er powered by a Bosch active motor. I've covered over 3000 miles since buying the bike in 2014.

I had my first issue today, 16 miles into my ride as a I aproched the top of a hill ( in a low gear and tour mode) the power delivery started to pulse and with each pulse the power reduced until over the space of 30 meters there was nothing. The display did not change, I had 4 bars remaining on the battery and a changing the power settings made no difference.
I sat for a few minutes planning my trip home (without assistance) but when I got underway everything was back to normal and stayed that way for the ride back home.

I don't know if it's relevant but the bike hasn't been back to the dealer since the day I brought it, ( I realy don't like the attitude of the owner and wish there was someone else local to me I could use.)

Anywho, do any of our Bosch owners know of this issue and what I should do about it.
Thanks in advance for any advice given.

 

[Fordulike]

Might be a stab in the dark, but has the bosch system got one of those magnets on the wheel to tell the controller the wheel is turning?
If it has, then that might be dirty or have shifted slightly, so the controller isn't picking up a signal and switching off.

 

[Gringo]

Yes it has a magnet but that was ok as the speed was still displayed correctly.

 

[Kuorider]

Another guess, but how hot was everything ? Is there maybe an overheat protection on the motor cutting out to protect it, then re setting when cooler.

 

[Gringo]

Not atall hot, I don't ride hard or fast.
I was kinda hoping someone may have had experience of the Bosch system and recognised my problem

 

[Wander]

... since buying the bike in 2014.

I don't know if it's relevant but the bike hasn't been back to the dealer since the day I brought it, ( I realy don't like the attitude of the owner and wish there was someone else local to me I could use.)

Even so think it might be worth getting it back to the dealer. Normally electrics warranty is two years so you may well still be in time & at least it gets your issue registered as within the two years (if you are?)

 

[Gringo]

It happened again on Saturday,
20miles into my ride and the power fades to nothing half way up a steep climb. I had to push it to the top and ride on for a bit unpowered, the display still shows the speed.
I turn everything off and took 5 minutes, when I switched it back on I got error code 503 but the power was back and stayed on for the 17miles home.
Today at the dealership there computer showed no history of any error? and they found no fault, suggesting I keep my rides local for a while.
I should add I'm using a new magnet and at no time did I lose the speed display.
I'm 3 months out of warranty and loosing confidence in its reliability.

 

[soundwave]

503 is speed sensor error so if its not the magnet is not in the wrong place id check the connector to the motor has not come loose.

if thats ok id replace the sensor and try that.

https://www.adrenalinatv.co.uk/shop/components/xduro-performance-emtb-ebike-pedelec/bosch-speed-sensor-cable/

 

[Gringo]

I'll keep riding with my fingers crossed. So far it been a temporary fault and after a rest it still got me home. If & when it returns I'll be looking under the covers

 

[soundwave]

if you got a crank puller you can whip the side of in less than 5 mins

 

[MarkH]

The Bosch magnet is a lot stronger than a normal cycle computer magnet, so only use the Bosch magnet to avoid speed sensor errors.

Did the dealer recently perform a software update? A 2014 bike would have definitely needed one.

You may find that the speed sensor wire is faulty, if so its low cost and easy to fit.

Good luck.

 

[Gringo]

OK so it's happend on two different magnets, each magnet has been in use ( on different wheels ) for the past 3000 miles without issue.
Now I have the latest update and I am just waiting for the chance to get out for a dry test ride of atleast 20miles ( both previous faults were well into a decent ride ) if Saturday's weather sucks I'll get the covers off and clean the connectors, if it's dry I'll probably just ride it

 

[kinega]

I had similar problem on mine. Dealer did software update initially & was OK for a week. Next visit they found connector on battery slightly out of shape because the little plastic cover thing was missing that goes over the terminals on the battery. Terminals realigned & cover fitted it has been absolutely perfect for the last couple of months.

 

[Gringo]

I'd finaly got the crank arm off and looked at the speed sensor plug, gave it a clean and squirt of switch cleaner but everything looked clean and tidy anyhow. Since then I've managed to do a shortish ride ( 15 miles ) without issue!
So yesterday (Sunday) I went for it 38 miles into my ride and "503 error" fortunately the quick way home was only 6miles and during that the fault went away
What to do ? I do love the bike But If the dealer can't find a fault how can I trust the bike on anything but short rides ? I'm considering selling up and getting something new but I wouldn't want to pass my problems on to a private buyer that only leaves a PX at a dealers.
Decisions Decisions

 

[RobF]

A squirt of switch cleaner on the display connectors is worth a try.