Help! Bosch 400Wh battery sudden death

mrchumpley

Finding my (electric) wheels
Nov 13, 2020
7
1
I have a three year old Trek TM400 with Bosch Active Line motor and 400Wh battery. Absolutely no problems with it until I cycled home the other night (I commute about 17 miles three times per week) and took the battery in as usual. It was down to one bar of charge. Plugged it in to the charger. I saw the light come on. Next morning put it on the bike and nothing. Plugged back into charger - no lights came on. Tried different sockets. Tried charging it on the bike. Tried all the usual tricks (cleaning terminals; holding the power button down on the battery for 30s; etc.) but it appears to have just died.

It's annoying because although the bike has done nearly 5000 miles, the battery seemed fine. No really noticeably reduction in performance. Until it suddenly just died.

Does anyone have any suggestions other than taking it back to the shop?

Cheers

Nevil
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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Check the charger for a fuse, inc the wall plug.
 

mrchumpley

Finding my (electric) wheels
Nov 13, 2020
7
1
Thanks - did that already. It's not that. And the battery does get slightly warm when plugged in, just no apparent 'life' in it.
 

mrchumpley

Finding my (electric) wheels
Nov 13, 2020
7
1
Thanks.
Yes, I've decided it's nothing I can sort out myself and have booked it in to be looked at next week.
I'm really just after reassurance that it is fixable, or that it has happened to others and to find out what happened in other situations where this occurred.

Cheers
 

stevenatleven

Pedelecer
Apr 18, 2011
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Fife
Happened to a friend of mine 400w Bosch battery, wouldn't hold a charge after 4 years.
Bosch agent said it was scrap and advised new battery. I contacted Jimmy at BGA and he said he could recell some Bosch cases but she decided to buy a new Bosch one for the warranty.
It was a couple of years ago so maybe things have moved on with with the alternative battery repair/re cell market. Think Bosch will just offer to sell you a new one and keep your old one.
 

Poolepete

Pedelecer
Aug 14, 2018
94
93
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Poole
I had exactly the same issue with the same battery, and under near identical circumstances. The only difference was my bike had 3000 miles and two bars on the battery before I put it on charge. I took it to the LBS, they could not get any reading from the diagnostics. It was completely dead. Fortunately for me, the bike was less than two years old and Bosch sent out a replacement without delay.
 

mike killay

Esteemed Pedelecer
Feb 17, 2011
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Sorry to hear of your problem. Try Jimmy at BGA, Bosch batteries are designed to not be re-celled. You might think that this is a restraint of trade, outlawed in the almighty EUSSR, but Bosch slip around that law by maintaining that even they cannot repair them.
Jimmy can still repair some Bosch batteries but not all. He does give a warranty.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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A Bosch dealer can do a diagnostic test but isn't able or allowed to open the battery for any repair, also Bosch do not repair them. Sadly out of warranty one can only fork out good money for either a new one or contact Jimmy to have it re - celled for about 50/60% of the Bosch cost. Like Steve my brother also had his re-celled a few years ago by Jimmy with an increase of wh from 374wh to 490wh.
 

soundwave

Esteemed Pedelecer
May 23, 2015
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the batt has to be working and charging or new cells wont work as it is a bms problem and not fixable as once the bms looses power that's it and game over.

jimmy can only recell batts that are still working and charging so it is a bin job.
 
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mike killay

Esteemed Pedelecer
Feb 17, 2011
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the batt has to be working and charging or new cells wont work as it is a bms problem and not fixable as once the bms looses power that's it and game over.

jimmy can only recell batts that are still working and charging so it is a bin job.
Amazing really, seeing that the Green party is strong in Germany.
 

mrchumpley

Finding my (electric) wheels
Nov 13, 2020
7
1
Thanks for all your replies! It's really helpful to know what the options are.

It does seem like another shocking example of 'inbuilt obsolescence' if Bosch can't/won't repair them. I imagine there must be a market for recycling these sort of batteries?

Just dropped bike at LBS but from what you've all said I guess I know what's coming.

Cheers
 

Bullet

Finding my (electric) wheels
May 31, 2020
18
15
Cheshire
I have a three year old Trek TM400 with Bosch Active Line motor and 400Wh battery. Absolutely no problems with it until I cycled home the other night (I commute about 17 miles three times per week) and took the battery in as usual. It was down to one bar of charge. Plugged it in to the charger. I saw the light come on. Next morning put it on the bike and nothing. Plugged back into charger - no lights came on. Tried different sockets. Tried charging it on the bike. Tried all the usual tricks (cleaning terminals; holding the power button down on the battery for 30s; etc.) but it appears to have just died.

It's annoying because although the bike has done nearly 5000 miles, the battery seemed fine. No really noticeably reduction in performance. Until it suddenly just died.

Does anyone have any suggestions other than taking it back to the shop?

Cheers

Nevil
I've got bosch battery and the charger failed just inside 2year warranty so they replaced it, my dealer Birkenhead cycles sorted it for me. Could it be faulty charger?
 

mrchumpley

Finding my (electric) wheels
Nov 13, 2020
7
1
I've got bosch battery and the charger failed just inside 2year warranty so they replaced it, my dealer Birkenhead cycles sorted it for me. Could it be faulty charger?
Unfortunately the bike is out of warranty. We do have two chargers and both don't do anything, although the battery does get warm when connected to both of them. Just no 'life'. I'm guessing it's the Battery Management System, which I'm guessing is just a circuitboard, which I'm guessing should be easy to replace, but which apparently no one 'does', not even Bosch.
Very annoying.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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Bosch can't do it because they don't make the batteries, the manufacturing wll be out sourced somewhere (Japan maybe ?).

MY brother (how & with who I don't know) sent one of his Bosch batteries back to Germany, they did contact him to say sorry we don't repair and he never saw the battery again.
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
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Bosch can't do it because they don't make the batteries, the manufacturing wll be out sourced somewhere (Japan maybe ?).

MY brother (how & with who I don't know) sent one of his Bosch batteries back to Germany, they did contact him to say sorry we don't repair and he never saw the battery again.
That is appalling! They should at least have asked him if he needed to have it returned or not.
Or possibly they do not want their batteries being repaired by others, so get rid of it fast??
Very little that I read on Pedelec about Bosch, is inspiring in a positive way.....
I wonder if they know just how negatively they can affect some people, who have experienced problems, like the unfortunate people we see here too often?

Andy
 

Nealh

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That is appalling! They should at least have asked him if he needed to have it returned or not.


Andy
From what he heard back from Bosch was they were surprised that it was couriered to them in the first place and was unsure how he managed it.
This was some 2 or 3 years ago.
 
Last edited:

Danidl

Esteemed Pedelecer
Sep 29, 2016
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From what he heard back from Bosch was they were surprised that it was couriered to them in the first place and was unsure how he managed it.
That would make sense . The problem with 400Whr Li Ion is that they are considered dangerous for air freight.
 

vfr400

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Jun 12, 2011
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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That would make sense . The problem with 400Whr Li Ion is that they are considered dangerous for air freight.
My guess is it went by road then air, but as I say a guess.