Meeting with Bosch

[flecc]

Is there anything - technically or patent-wise - to stop another company producing a pattern replacement battery?

Possibly not, since there is a precedent for doing just that. The second series Panasonic unit also has much sophistication with a five connection battery managed jointly by the BMS, motor unit software and charger software.

At one point Kalkhoff started buying only the power units from Panasonic and fitting a battery jointly designed by BMZ and themselves, using the existing Panasonic mountings and connections with the same battery management, even copying the dual purpose metering arrangements and sleep mode facility. Since I've no doubt a giant like Panasonic would also try to protect their designs, clearly there are ways past that.

 

[Martin@e-bikeshop]

Doesn't that make all this talk of the sophisticated electronics in the Bosch system nothing more than a myth then? It mustn't be that difficult to get the Bosch system to work with a none Bosch battery set-up.

I don't know the in's & out's of how he was doing it, this was not explained. However as a dealer he probably had access to advanced diagnostics tools and diagrams. He could even have been using BMS's out of old battery's with new cells.

I'm sure with advanced knowledge / skills of the Bosch battery it can be done. In fact we are not saying that it is impossible as it clearly is not. But none of it with the stamp of approval from Bosch, so therefore no back-up and CE certification.

Regards
Martin

 

[Martin@e-bikeshop]

It just so happens that I do have a spare brand new 400Wh PowerPack still in the box at my Alton store.
I'm sure if you paid me a visit this side of Xmas I may be feeling jolly and in the Christmas spirit.
This could possibly leave me at an advantageous price and maybe even a mince pie on the side

Who would have thought this comment would have prompted a few PM's in the last half hour haha.

Regards
Martin

 

[RobF]

Who would have thought this comment would have prompted a few PM's in the last half hour haha.

Regards
Martin

Well you can all naff-off - hopefully - as I've just pinged through my order.

My thanks to Martin for sorting the job on a Sunday evening.

 

[El Champiero]

Good advice by Martin there on the battery. Only attempt modification if you have a very good understanding of how battery packs work and how BMS circuits function - and that you are prepared to take the risks.

Very cheap "new" Bosch batteries will NOT have the correct cells inside them. You can actually get hold of Bosch empty cases, called "dummy batteries". No doubt someone was being very devious with that perk and filling the cases with poor quality cells.

Only high quality, high drain cells can be used which are capable of handling 10A and greater discharge currents. Anything less really wont less very long.

 

[tillson]

On the face of it, these batteries do seem expensive when compared with budget Chinese offerings, and I used to think that we were being screwed by the likes of Panasonic and Bosch with their seemingly high replacement replacement battery cost.

With time, I have learnt that quality batteries with a decent guarantee give a good service life. I can only speak for Panasonic, because that is the only brand that I have owned, but I suspect that Bosch are probably similar in quality. My Panasonic battery is 5 1/2 years old and has done more that 15500 miles. It still copes easily with my 20 mile round trip commute and looks like it will last through this 2013 /2014 winter. If it does live until the spring, then I will be confident that this battery will pass the 6 year mark.

I think that it is reasonable to pay £500 for this sort of mileage and life expectancy from a battery. The numbers make sense and an Ebike becomes a realistic option as a means of transport.

 

[Martin@e-bikeshop]

Well said tillson,

Its the old saying - You pay for what you get.
By buying cheap, you often buy twice and this can work out unpractical & expensive in the long run.
P.S nice review of the Panasonic battery there. I have been selling Panasonic systems for just over 5years now and am yet to have a customer back for replacement..

Regards
Martin

 

[El Champiero]

True - the cells themselves (i.e. Panasonic or Samsung etc - Bosch uses Samsung cells in the 2011 and 2012 batteries) are relatively expensive to purchase and make up into a pack. You then have to connect up the electronics and Bosch then got someone to make the BMS which is pretty sophisticated. Volume wise, they can probably get the cost price down to about £250 per battery. Add on the profit margin and there you have the £500 price tag.

You are paying for the reliability for sure. The BMS inside these batteries has a discharge cut off of about 3.4V per cell. This is one of the reasons they last a very long time.

Not so sure about the longevity if you de-restrict your Bosch or if you have the Sport model of the motor. Speaking from experience, I can say that my battery pack after 18 months of use (about 12 in de-restricted mode) started to drop noticeably in capacity. This was used about 3 times per week for a 24 mile commute (12 each way). When I started using it de-restricted, I used to be able to do a 24 mile round trip in Tour 1 mode on one single charge. After 18 months, I had to charge it after the first 12 mile leg of the journey to work as it then started to drop to 3 bars from 5 (instead of 4 bars from 5). I did used to also use it when I was riding it de-restricted quite often in Sport 2 mode and charge it once a work and once at home. This obviously didn't do it much good.

Basically, the more hard use a battery has and the subsequent increased amount of times you then need to charge it won't do it much good.

If anything, the Bosch motor is fine handling the extra burden of being de-restricted. The battery is not as forgiving. Therefore, Bosch do have a valid point to discourage tampering with their system - there are risks involved.

 

[El Champiero]

At peak power the motor (even the restricted motor) can draw over 500W in Speed 3 going up a steep hill for example. At 36 Volts this gives a current draw of 13.8A.

 

[Artstu]

At peak power the motor (even the restricted motor) can draw over 500W in Speed 3 going up a steep hill for example. At 36 Volts this gives a current draw of 13.8A.

Almost every ride I do sees me going up steep hills in turbo, I've seen 4 bars of the display disappear on one climb! I guess my battery isn't going to last long.

 

[atheo]

This is exactly why ,as I ride derestricted,I purchased a second Bosch battery.

 

[Deleted member 4366]

Not so sure about the longevity if you de-restrict your Bosch or if you have the Sport model of the motor. Speaking from experience, I can say that my battery pack after 18 months of use (about 12 in de-restricted mode) started to drop noticeably in capacity. This was used about 3 times per week for a 24 mile commute (12 each way). When I started using it de-restricted, I used to be able to do a 24 mile round trip in Tour 1 mode on one single charge. After 18 months, I had to charge it after the first 12 mile leg of the journey to work as it then started to drop to 3 bars from 5 (instead of 4 bars from 5). I did used to also use it when I was riding it de-restricted quite often in Sport 2 mode and charge it once a work and once at home. This obviously didn't do it much good.

Basically, the more hard use a battery has and the subsequent increased amount of times you then need to charge it won't do it much good.

If anything, the Bosch motor is fine handling the extra burden of being de-restricted. The battery is not as forgiving. Therefore, Bosch do have a valid point to discourage tampering with their system - there are risks involved.

At peak power the motor (even the restricted motor) can draw over 500W in Speed 3 going up a steep hill for example. At 36 Volts this gives a current draw of 13.8A.

That's very disappointing, being a shorter life than most Cheap Chinese ones running at the standard 15 amps. My original 9aH Sunlova battery is still going after 3 1/2 years and 3000 miles at 18 amps, and the whole bike only cost £620.

I think that your cost of £250 is way too high. BMZ make other batteries with the same cells and the same standard of build, which they sell to other OEMs for less than that. The rise in price to £500 happens in several stages after it leaves the BMZ factory at a cost less than £200 (based on their other batteries prices).

Using a dongle on a Bosch doesn't change the peak current in any way, it only releases the speed limit, so it can't effect the battery in any significant way other than the fact that the battery will be used more above 15mph, so your wH/mile will go up,which will ultimately wear-out the battery sooner.

I think that you've also under-estimated the current flow. I've never measured the current, but I'd estimate that 18 amp would be more like it - maybe 20.

 

[trex]

Bosch batteries are fairly priced, no question about that.
But is a Bosch battery better than a Chinese one? this notion has no basis in fact. Many Chinese batteries are built with Samsung, Panasonic or Sony cells - same quality as the Bosch.
Unlike Bosch, none of the Chinese batteries have software lock.

 

[El Champiero]

Maybe it might be closer to 20A to 25A peak current draw. The new Panasonic cells can handle this sort of peak current so I am assuming they will do the job well.

Only time will tell how well the modified battery lasts well - it certainly looks like it should.

Taking a guess at the battery cost price - I don't really know how much Bosch can beat the price down on thousands of batches of 40 Samsung cells each made up into a pack with custom BMS. However, in my case - if I can get a re-cell done at about £230 with some electronics work on my part, and it lasts well then to me it's good value compared to spending over £500 for a genuine Bosch one.

 

[Electrifying Cycles]

I did find that battery story interesting when my collegue told it. I suppose it also shows Bosch will drop you in a shot if they find you doing something they do not like.

 

[Martin@e-bikeshop]

Morning guys,

After this interesting thread conversations yesterday. I decided to set out to write an article to explain how to extend the life of your Bosch eBike battery and how to maintain it.

To keep things clean I have started a new thread on this forum here - http://www.pedelecs.co.uk/forum/electric-bicycles/16441-how-look-after-maintain-your-bosch-ebike-battery.html#post201722

Regards
Martin

 

[Deleted member 4366]

Overall a very good instruction, Martin, but with two exceptions: The opening sentence is just sheer sales spiel, which is OK, but you need to add the word "some" in the second sentence to make it plausible.

They offer a superior range, reliability & longevity compared to some other batteries.

In the section "Can I open up the case and replace the cells inside myself?", you say that there's a risk of electric shock. I can't see how that can happen with only 36v even with the charger plugged in. The only health risk is burning your fingers if you short something out. I think that you should change it.

 

[El Champiero]

Whilst carefully cutting the nickel tabs in my battery (after first taking the BMS board off and using plastic covered cable cutters) I caused a small short. There was a extremely tiny blue spark which caused no charring on the tab. No drama caused to be honest. Batteries were then all tested in a torch and left to run to about 3V. All seemed to last the same time and they all charged OK too. My guess is that the cells have lost some capacity (maybe 10-15%) due to the large amount of use and charge cycles over the last 18 months. I think they'll be absolutely fine for someone using some of them for e-cigs or a torch. Bearing in mind that they are not individually protected from over discharge unless connected to a BMS.

 

[Martin@e-bikeshop]

Overall a very good instruction, Martin, but with two exceptions: The opening sentence is just sheer sales spiel, which is OK, but you need to add the word "some" in the second sentence to make it plausible.

They offer a superior range, reliability & longevity compared to some other batteries.

In the section "Can I open up the case and replace the cells inside myself?", you say that there's a risk of electric shock. I can't see how that can happen with only 36v even with the charger plugged in. The only health risk is burning your fingers if you short something out. I think that you should change it.

Morning Dave,

Thanks for taking the time to read it. Much appreciated.
I have made some amendments as advised. Should all be perfect now.

Regards
Martin