Latest progress on cell upgrade for Bosch battery.

[El Champiero]

Dear all,

I have just had a re-cell done on my Bosch 2012 e bike battery with new Panasonic high drain NCR18650PF cells. Haven't quite got round to putting it all back in the case but so far the cells are charging perfectly. I sent off the internal plastic cell holder to a factory in China I found on Aliexpress - This cost about £10-12. They built up a new battery for me using the existing cell holder and posted it back to me for an all inclusive cost of just £216. I also bought a new dummy case as my old was a bit battered. This cost me £90 from Germany. So all in, a new higher capacity 11.6aH or 417.6wH battery cost me just over £300 with me to do a bit of soldering and assembling. This saves about £200 on a new 400wH battery from Bosch.

When I get round to it, I'll put some kind of guide up here on how to do it. For now though, here is the place in China who were able to make up the battery for me. I asked them to use 0.15mm thick pure nickel strip. They also used my drawing of the battery on their website.

http://www.aliexpress.com/snapshot/313311157.html

 

[El Champiero]

Photos of the disassembled pack
http://www.flickr.com/photos/lucasimo/sets/72157637969642213/

http://www.flickr.com/photos/lucasimo/sets/72157638294396215/


New pack photos (click on the photos for supporting information)
http://www.flickr.com/photos/lucasimo/sets/72157640112603195/

 

[patpatbut]

I thought Bosch battery is tricky as after re-celling the pack it wont work on the bike. I heard someone in this forum sayying this...

Pat

 

[Martin@e-bikeshop]

I thought Bosch battery is tricky as after re-celling the pack it wont work on the bike. I heard someone in this forum sayying this...

Pat

Hi Pat,

This is true on the newer 2014 packs. The old packs can be opened, still voids your warranty though, not just on the battery but the whole electrical system too.

I know you have been updating me on this via the emails ElChampiero but how many man hours have you put into this to date?

Think it was a few months ago when we first spoke, although I understand the shipping to and from China can take some time.

Hope it all works out OK!

Regards
Martin

 

[El Champiero]

I just put it on the bike and went for a quick ride - works absolutely fine. I cannot see how the BMS could possibly "know" that the cells have been replaced as it only senses voltage across a range of cells. I think this is just scare stories to discourage people from saving £200 on a new battery. More tests to follow in due course.

 

[El Champiero]

Man hours I reckon in total about 1 to open up the case and 2 to re-assemble to pack inside the case with the ribbon cable to solder on to the new cells. I still can't quite see how the new 2014 packs can have an in built shut down in them - perhaps they have but I have my doubts. My guess is that this is definitely possible to defeat if indeed they do have this feature. Is this warning from first hand experience or from the German e bike forums?

 

[El Champiero]

I also have a genuine non tampered with Bosch battery as a spare...

 

[Scimitar]

Man hours I reckon in total about 1 to open up the case and 2 to re-assemble to pack inside the case with the ribbon cable to solder on to the new cells. I still can't quite see how the new 2014 packs can have an in built shut down in them - perhaps they have but I have my doubts. My guess is that this is definitely possible to defeat if indeed they do have this feature. Is this warning from first hand experience or from the German e bike forums?

Some laptop batteries have had inbuilt shut-downs for years. Often a crowbarred chip, unreplaceable.

 

[KirstinS]

I just put it on the bike and went for a quick ride - works absolutely fine. I cannot see how the BMS could possibly "know" that the cells have been replaced as it only senses voltage across a range of cells. I think this is just scare stories to discourage people from saving £200 on a new battery. More tests to follow in due course.

It is quite easy to do. Lots of matika power tool packs have chip inside on the BMS that after 5 failed charges shuts the pack down (perhaps one cells goes below 2.6v for example)

the chip bricks the pack forever - even if you change all the cells out for brand new ones it will never charge again.

Matika says it's for saftey

Hmm, I don't buy it - it's to sell more batteries !

 

[Cyclezee]

Dear all,

I have just had a re-cell done on my Bosch 2012 e bike battery with new Panasonic high drain NCR18650PF cells. Haven't quite got round to putting it all back in the case but so far the cells are charging perfectly. I sent off the internal plastic cell holder to a factory in China I found on Aliexpress - This cost about £10-12. They built up a new battery for me using the existing cell holder and posted it back to me for an all inclusive cost of just £216. I also bought a new dummy case as my old was a bit battered. This cost me £90 from Germany. So all in, a new higher capacity 11.6aH or 417.6wH battery cost me just over £300 with me to do a bit of soldering and assembling. This saves about £200 on a new 400wH battery from Bosch.

When I get round to it, I'll put some kind of guide up here on how to do it. For now though, here is the place in China who were able to make up the battery for me. I asked them to use 0.15mm thick pure nickel strip. They also used my drawing of the battery on their website.

http://www.aliexpress.com/snapshot/313311157.html

Hi El Champiero,

If your rebuild proves successful in the long term you could have business opportunity by providing this service.
I though wonder how many people would take the risk if it invalidated warranty for the entire electrical system?
Did your original battery fail and if so was it not covered by warranty?

 

[Geebee]

It is quite easy to do. Lots of matika power tool packs have chip inside on the BMS that after 5 failed charges shuts the pack down (perhaps one cells goes below 2.6v for example)

the chip bricks the pack forever - even if you change all the cells out for brand new ones it will never charge again.

Matika says it's for saftey

Hmm, I don't buy it - it's to sell more batteries !

A mate got me half a dozen returned Makita packs, only 2 had a dud cell, a couple a bad connection to a cell and the others I could not fault, with the exception of the 2 dud cells all the other cells have tested perfect and are doing duty in my torches and other toys.

 

[Gringo]

Interesting

It is quite easy to do. Lots of matika power tool packs have chip inside on the BMS that after 5 failed charges shuts the pack down (perhaps one cells goes below 2.6v for example)

the chip bricks the pack forever - even if you change all the cells out for brand new ones it will never charge again.

Are you saying the BMS fails & no longer allows the remaining good cells to be charged.
Or
The BMS kills the remaining good cells making the whole thing useless.

I'm asking because in the past I've built RC packs (NiMh) using good cells from dead power tools.

 

[shemozzle999]

Hi El Champiero,

Looks like a good clean and most importantly a safe re-cell, well done!

 

[El Champiero]

My original battery that came with the bike wasn't damaged as such. I just wanted to see if it was actually possible to re-cell it. I also bought a cheap new genuine 288wH battery from Germany in case my experiment didn't work. Turns out that it is certainly possible, at least for the pre 2013 Classic Plus Bosch range of batteries. I now have a spare 288wH battery which has had very little usage. I might hang on to it or sell it at a later date.

Warranty issues may well surface - but for example, when it comes to motor bearing wear (which I am sure may well be an issue in the next few years) Bosch just replace the entire motor. The dealer sends it back to them via Magura. I have a good relationship with my local bike shop who are aware of the SX2 derestriction dongle I have fitted - they take a pragmatic approach to warranty issues. In fact there has only been one I claimed for which was for premature bearing failure in the motor about 2 months after I bought the bike. A new motor was sent within 10 days. I wouldn't bother claiming a warranty issue for the battery in any case if my modified one broke.

Sounds like Bosch have wised up then for 2014 if they have in fact fitted "suicide" chips. It would be a challenge to re-cell these ones. One way I think it could be done would be to apply a constant 0.5A current at 36 V to the BMS as a "piggy back" whilst disconnecting all the cells. Not exactly a safe option working live like that. The BMS would have to be disconnected from the cells very carefully and remain powered up to make it "think" it was still connected to the cells. The other option could be to plug the charger in powered up and disassemble the cells accordingly. Or just not bother risking a fire and stick to modifying the pre 2014 batteries!

I suppose I could do a re-cell service for about £100. This would save people about £100 on the cost of buying a new 400wH battery from Bosch. Depends on how people want to go as my modified battery would not come with a Bosch guarantee but I guess I could offer one for 12 months. Not sure about my kitchen table getting crammed up with batteries....

 

[Electrifying Cycles]

Funny enough I got an email from a Chinese company trying to sell me Bosch batteries (2013 version) and Panasonic batteries (for their crank drive). Obviously they are not the real deal but I would imagine some will try. Not interested myself but I can understand why people want to save the money. Although just a case of weighing up whether it is worth it.

There was an interesting story (Martin already mentioned this I think) raised at Bosch training about a dealer recelling dummy batteries and selling them as the real deal. For dealers I get the impression Bosch would drop you like a stone if they caught you doing things they do not like. I am guessing on the dongle side they might be turning a blind eye?

 

[jackhandy]

Bosch - turn a blind eye on a warranty issue?

Only time will tell.

 

[Electrifying Cycles]

No I meant dealers selling them. If they were aware any warranty would be void. However it is not possible to know whether the diagnostics kit can tell. Dealers have less options than Bosch and Magura would have. They are a very large company and if a dealer was doing something they did not like you got the impression they would not mess around.

 

[El Champiero]

I certainly think they are turning a blind eye on the dongle issue as many people are running their Bosch bikes with it now. With batteries I can understand that they would be pretty annoyed at someone offering a re-cell service. However, I doubt there is much they can do legally as even if I did this (I probably wont bother due to the massive cost of shipping the finished batteries out) I wouldn't be attempting to sell the modified battery as a genuine new Bosch battery. In any case, the battery is not owned by Bosch - it is owned by the person who bought the bike. The safest option is for people to only attempt this (if they want to) after 24 months by which time the guarantee on their battery will be expired in any case.

The only potential problem I can think of is if they had an electrical issue on their bike and Bosch then wanted to examine the battery. As to what exact electrical issue I cannot be sure. If they then saw different cells inside then they would not honour the warranty. In any case, the BMS board inside the battery case does not need special setting up when replaced - hence you can put any compatible Bosch battery in there). The motor unit, however, does require some kind of special setting up to make it work if a new one is put in. I think the dealer has to input some kind of code.

Most problems with the Bosch unit will surely come from the motor unit due to mechanical wear - not the battery itself. The motor unit is where Bosch have had the vast majority of warranty issues.

So in conclusion, if people want to do this and save about £200 then by all means do it.

I took the bike out today with the new battery (running in derestricted mode as usual) and did a total 4 mile trip in Tour setting 1 going up a few hills to my gym and then back again. Starting voltage was 41.7. After finishing the ride I left the pack for 20 minutes and measured the voltage at 40.9. In total, a voltage drop of 0.8V. (I don't know how much current the motor draws). No range bars on the HMI or the battery have yet gone below 5 lights.

Before putting the pack back together I took time to balance charge each group of 4 cells so they were all reading either 41.3 or 41.4V (it may well be worth me getting a proper balance charger if there is a next time)

Ill be taking it out on much longer rides to see exactly what I can get out of it using my standard commute in comparison with my existing 288wH battery. I reckon a few long runs on it in Tour 1 setting and subsequent recharges will then give me a reasonable measure of how it is performing.

 

[Deleted member 4366]

Thanks for sharing that project.

There's a couple more things I'd like to know to complete the story. Is there some sort of hand-shaking between the controller and the BMS that prevents the use of an alternative battery? I thought I heard that something is logging charge cycles, in which case there's still the possibility that the battery could shut down after a fixed number of charges like some laptop batteries do " for safety reasons".

Another thing that I can think of. Two of the wires from the battery are the main power wires. What would happen if you cut them, and wired in a different battery. leaving the old BMS powered and connected to any data lines? Any intelligence in the BMS wouldn't see any discharge.

 

[Electrifying Cycles]

Charging cycles are logged, this is part of the diagnostic report. D8veh not sure wiring another battery would work. I know someone who tried to wire Bosch battery to a different motor and even when using official Bosch wiring to the motor it did not work. They did not want to use Bosch bikes and instead wanted to borrow batteries to use on older bikes.

I can understand people wanting to make repairs to save money. We would all love the prices of batteries to come down. We will be offering discounts on battteries if people buy a bike from us but what is really needed is a price decrease. However I can not see this happening.

Anyway interesting read.