Help please! Bosch won't start

SoSurrey

Just Joined
Jan 28, 2024
2
0
Hi all,

I have an odd one with my Bosch-powered e-bike: the battery and console are connected to each other, but the motor won't start. I was hoping someone may have encountered this before and have a solution, or just general advice.

The tech:
- It's a factory fitted Purion console
- It's a Bosch performance CX motor (3rd gen, I think)
- It's a Bosch Powerpack 500 battery

I know it's not a battery problem, as I have another e-bike that uses same battery type, and I can swap them about on that bike and they both work fine. Neither works on this bike.

The issue:
- Battery clicks into place fine.
- You cannot then turn it on with the on switch on the Purion console, as you should be able to to (see vid)
- If you switch on the battery manually, by pressing the button on the battery itself, the speed setting (eg Turbo/EMTB/Tour/Eco) comes on with battery life for a second or two, then it switches to range, then it switches off.
- you can do this over and again with the same result

What I have tried:
- taking it to the local E-bike shop, who ran Bosch diagnostic computer and found no errors.
- cleaning an re-aligning the sensor magnet on back wheel.
- 'bouncing' back wheel of bike in hopes it's a dodgy connection and this will jolt it into action
- pedalling like hell with no motor and pressing the battery button while it's going along, in the hopes of jump starting it
- doing the above on a bike stand.

None of these give a permanent fix. Now and again they will work, but I suspect that's more luck than anything else.

Sometimes the bike starts fine (rarely)

If the bike does start, it runs fine 99% of the time - occasionally cuts out after a minute of so, but if it's been going for ten mins or more, it's pretty reliable: doesn't cut out in the middle of a long ride (thankfully!)

Link to video here on Tube showing the issue: https://youtube.com/shorts/3BcDcHvV1R4?feature=share

Grateful for advice and thanks in advance!
 

soundwave

Esteemed Pedelecer
May 23, 2015
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saneagle

Esteemed Pedelecer
Oct 10, 2010
5,170
2,501
Telford
I'd start by dropping the motor and taking the side off to check every connector. if that doesn't reveal anything, see if you can temprarily borrow a different Bosch display, and if that doesn't work, either open the motor to see if the main board is water damaged or send it to the above place to sort out.
 

AntonyC

Esteemed Pedelecer
Apr 5, 2022
280
126
Surrey
I think the key thing is that it's intermittent and seems centred on starting up time. I don't know Bosch stuff but I'd suspect the On button itself, or possibly the display cradle contacts if the display's removable or the display to controller plug/s.

Some spray contact cleaner on all the above around the edges lightly shouldn't hurt but use the real thing not WD40. After that hold the display's On button and rock and wiggle it for a bit to see if it turns on more often than before, the aim being to diagnose not necessarily fix.

Are the displays known to be free of pairing codes? If not it would be ideal if you can get a shop to test fit a display or do one sale or return.
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,464
6,365
its can bus comms with no error code it could be anything
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,725
1,256
If it is capable of running some of the time then it is capable of running all of the time. No diagnostic codes suggests not motor and not battery.

I suspect intermittent imperfect contact on one of the small wires between display and rest of system.

On my admittedly Shimano setup, I have several times had such an intermittency when using the remote battery mount that my solar setup requires. Always fixed by making the battery mount terminal block (two big power connectors and two small signal connectors) more tightly squeezed into the battery.
 

AntonyC

Esteemed Pedelecer
Apr 5, 2022
280
126
Surrey
This might help: link.
" I also tried replacing the batteries in the Purion [snip] (also verified healthy batteries with a multimeter)"

If that's the issue the On button probably works while the display's lit up.
 

Kiwi Pedelar

Finding my (electric) wheels
Jan 31, 2024
8
2
My wife’s Bosch powered Allant occasionally has this issue. It only seems to happen if you insert the battery and then try and turn it on immediately. Instead, if you connect the battery and wait five minutes before turning on the LCD it seems to come up OK.
 

dalemanuk

Finding my (electric) wheels
Apr 22, 2017
10
3
uk
might be worth reading this
 

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