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Battery pack revision for Bosch 400

Posted: Aug 18 2019 1:35pm
by ThomasEekels
Hi,
I have dismantled my Bosch 400 active line battery pack, as it was dead.
Finally, from the 40 batteries, 4 were still good, 4 were not so good and the remaining 32 were dead, zero volt or even minus 0.04.
It is a 40 battery pack, 10s2p

Is my assumption that also the BMS is faulty reasonable?

I want to replace all batteries and the BMS. The BMS is not the most expensive part I this renovation.

The Bosch BMS has not only 13 balance wires , it also has a 3wire to the bicycle connector, that I don't see on regular BMS boards.
From the 13 wires, 2 are short circuited and the rest are wired to the 10 plus and to one minus.

Can I buy any 11 wire BMS and forget abut the 3wire to the bicycle ?

advice is appreciated.
Thomas

Re: Battery pack revision for Bosch 400

Posted: Aug 18 2019 2:34pm
by Joachim
dont waste youre time and money...dead bosch battery: 99.9% the bms is also damaged and the bosch drive system
needs the signals from the bosch bms to wurk.

use Search: bosch battery

Re: Battery pack revision for Bosch 400

Posted: Aug 18 2019 2:35pm
by neptronix
Your Bosch has a special communication system between the battery and bike. Therefore, you need their BMS ( unless someone's hacked it! ). You're going to need to decide whether to stick with their parts, or dismantle their proprietary system and run a DIY setup to drive the bosch motor. Unless they'e also screwed you by not putting a 3 phase motor in the case.. :lol:

Re: Battery pack revision for Bosch 400

Posted: Aug 18 2019 3:37pm
by ThomasEekels
Can I buy the original BMS somewhere ?
Has anyone bypassed the 3wire control to the bike ?

Re: Battery pack revision for Bosch 400

Posted: Aug 18 2019 5:29pm
by flippy
As soon as a single cell gets below 2v the bms commits suicide. You cant buy blanks because a unpowerd bosch bms means a dead bosch bms.

This is done to force you into the bosch ecosystem and dealership for maximizing profits. Its the apple of the ebike world.

Fun fact: the 300 and 400 powerpacks use the same cells, the bms just artificially caps the usable capacity on the 300 model.

Re: Battery pack revision for Bosch 400

Posted: Aug 18 2019 5:48pm
by neptronix
I have a pack here with a suicided BMS and all cells above 3v. Sometimes the die because they feel like it!

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 12:13pm
by ThomasEekels
flippy wrote:
Aug 18 2019 5:29pm
As soon as a single cell gets below 2v the bms commits suicide. You cant buy blanks because a unpowerd bosch bms means a dead bosch bms.

This is done to force you into the bosch ecosystem and dealership for maximizing profits. Its the apple of the ebike world.

Fun fact: the 300 and 400 powerpacks use the same cells, the bms just artificially caps the usable capacity on the 300 model.
Well, that was expected. It's dead.
so either I get hold of a new Bosch BMS, or I hack the bike to discard of the 3wire control ?
I can charge the new built with any 10s bms, but the bike needs the Bosch I understand....

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 4:02pm
by flippy
ThomasEekels wrote:
Aug 19 2019 12:13pm
so either I get hold of a new Bosch BMS, or I hack the bike to discard of the 3wire control ?
I can charge the new built with any 10s bms, but the bike needs the Bosch I understand....
1: good luck with that.
2: yes, welcome to the bosch ecosystem.

next time buy a bafang.

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 4:28pm
by neptronix
Option 3 is to bypass the proprietary stuff and free your bike like I mentioned.. IE run a new controller to the motor.

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 5:58pm
by flippy
neptronix wrote:
Aug 19 2019 4:28pm
Option 3 is to bypass the proprietary stuff and free your bike like I mentioned.. IE run a new controller to the motor.
and how would you do that? the controller is inside the motor. i got a bunch of detailed photo's of most used mid drives and apart from the bafang they all have the controller on the inside on a extremely custom pcb. only the bafang is universal.

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 6:59pm
by neptronix
flippy wrote:
Aug 19 2019 5:58pm
and how would you do that? the controller is inside the motor. i got a bunch of detailed photo's of most used mid drives and apart from the bafang they all have the controller on the inside on a extremely custom pcb. only the bafang is universal.
If it has 3 phases, there's a way to drive it.
Drill a hole in the drive and run phase wires out.

If you're lucky, it'll have hall sensors too. :)

Here's a guy who is driving it with a VESC ( some people have also played with other setups )
viewtopic.php?t=93831

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 8:37pm
by flippy
doing so would break the water seals, not something i recommend as the motor has zero protection for water or crap on the inside of the case.
the bafang is brilliant, all the electronics on the inside are driven by a potted box on the outside. its stupid easy to replace that controller.
and the bosch has a crank sensor, its useless without the magic sause from bosch and twitchy as hell if it is mounted even slighty wrong.

Re: Battery pack revision for Bosch 400

Posted: Aug 19 2019 9:03pm
by neptronix
flippy wrote:
Aug 19 2019 8:37pm
doing so would break the water seals, not something i recommend as the motor has zero protection for water or crap on the inside of the case.
You might not even have to drill holes out of the case. There's likely some thickish power wires going to the unit. Those could be reused and sealed with RTV or something else.

Re: Battery pack revision for Bosch 400

Posted: Aug 20 2019 8:03am
by ThomasEekels
Another out-of-he-box. idea.
If I can not get the original battery BMS, but rebuild the battery pack with ordinary 10S bms,
can I put the DIY pack parallel to an original Bosch pack ? Like charge it separately, but connect the decharge in parallel before the ride?
Just piggy bag both battery packs. The original pack will communicate with the bicycle, the 2nd pack will supply power in parallel...

is that feasible ?

Re: Battery pack revision for Bosch 400

Posted: Aug 20 2019 9:04am
by flippy
no, you cant because the bms is already dead.
neptronix wrote:
Aug 19 2019 9:03pm
You might not even have to drill holes out of the case. There's likely some thickish power wires going to the unit. Those could be reused and sealed with RTV or something else.
the connectors to the outside and its weather seals are on the controller board so that aint gonna work.

Re: Battery pack revision for Bosch 400

Posted: Aug 20 2019 8:48pm
by Hillhater
ThomasEekels wrote:
Aug 20 2019 8:03am
Another out-of-he-box. idea.
If I can not get the original battery BMS, but rebuild the battery pack with ordinary 10S bms,
can I put the DIY pack parallel to an original Bosch pack ? Like charge it separately, but connect the decharge in parallel before the ride?
Just piggy bag both battery packs. The original pack will communicate with the bicycle, the 2nd pack will supply power in parallel...

is that feasible ?
Sound like a strong possibility of killing the 2nd pack as well :roll:

Re: Battery pack revision for Bosch 400

Posted: Sep 01 2019 6:10am
by ThomasEekels
flippy wrote:
Aug 20 2019 9:04am
no, you cant because the bms is already dead.

Maybe my question was not clear: I intended a new battery with good BMS. and put the rebuilt battery, (without BMS) in parrallel after charging.

Re: Battery pack revision for Bosch 400

Posted: Sep 01 2019 8:20am
by flippy
ThomasEekels wrote:
Sep 01 2019 6:10am
Maybe my question was not clear: I intended a new battery with good BMS. and put the rebuilt battery, (without BMS) in parrallel after charging.
you understand that as soon as you disconnect a single balance wire from the new bms it is also toast?

swapping boards will require one massive wire-dance if you want to keep all the wires connected to anything all the time.