# Tesla module 12s conversion - succesfull prototype!



## boekel (Nov 10, 2010)

only half of the connections installed during test


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## Boxster-warp (Jun 22, 2014)

Hello
Wonderfull 5,3 kW/h Energy Storage.
But you have Not the Full power from the Tesla Modul.

Make the victron 37-50v?
Greetings Greenboxster


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## boekel (Nov 10, 2010)

They're for in a car.

8 modules 12s gives about 400 volts, lots of motors / controllers need higher voltages like this.

Half a Tesla 85kWh pack is plenty for a lot of cars, and much lighter than alternatives like Calb cells.


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## boekel (Nov 10, 2010)

This is my route:


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## oudevolvo (Mar 10, 2015)

Great job and thanks for sharing all those details!


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## itchyback (May 28, 2014)

wow awesome. can you tell what tool you used to cut the module? 

Also, how did you attach the bolts to the board?

loving this!


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## boekel (Nov 10, 2010)

itchyback said:


> wow awesome. can you tell what tool you used to cut the module?
> 
> Also, how did you attach the bolts to the board?
> 
> loving this!


With a spiral groove cutter for aluminum in a router. Path is CNC cut. after cutting and cleaning up I filled the groove with electrical grade silicone caulk.

the bolts are attached with a stud welding machine (capacitor discharge).

Both tasks are quite daunting, and took a couple of weeks to optimize.

I have orders for converting 16 modules, after that I might take orders for more.


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## Boxster-warp (Jun 22, 2014)

Hello
I want to make a ev conversion in Germany with 250volts.
Hmmm a good idea, where do you come frome netherland?
Greetings Boxter-warp


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## jimwebo (Mar 3, 2017)

Thanks mate for sharing this valuable information.
Other experts should learn from you.
A greeting .
I left some questions in the other post.
Jim


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## boekel (Nov 10, 2010)

Boxster-warp said:


> Hello
> I want to make a ev conversion in Germany with 250volts.
> Hmmm a good idea, where do you come frome netherland?
> Greetings Boxter-warp


20 km above Amsterdam.


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## NickNok (Mar 31, 2017)

Using Tesla's Battery Monitoring and Management system with a 12s Module:

It is now possible to Monitor and manage the Voltages and Temperatures for a 6s configuration Tesla Model S Module using the original Tesla BMB and some clever recent reverse engineering of the communication protocol and daisy-chaining the Boards.

Can one use two Tesla BMB's to monitor the 12s configuration you have created? (6 cells for each BMB). 

How could this be implemented? 

Is each BMB powered by the Module itself? Would powering two boards per "half" module cause issues? I would imagine that you would want to draw current from each of the 6 cells evenly otherwise it would induce an imbalance in the module over time?

As the cell configuration has been altered for the 12s layout, would it require new voltage taps for ALL of the 12 cells?? (I am assuming that the 6 original voltage taps are no longer usuable.) Is it impractical to get enough access at the individual cell level to add/remove voltage wiring?(its probrably glued together pretty good)

From what I have read, there are two temperature sensors for each module, one on the positive terminal and one on the negative terminal of the module. Can the 2 BMB's share and report this same information? It seems pointless adding two more?


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## Tomdb (Jan 28, 2013)

First of all a big thanks to Boekel, a package showed up today for me. I was expecting more bms board, those I did get however one was still attached to a tesla module that had been converted to 12s 

The Boekel conversion allows one board to remain fit in the stock location and work normally.

Wired up the second board to the remaining cells.

Now I can test my tesla bms software with multiple slaves in series.


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## Tomdb (Jan 28, 2013)

I can confirm the following.

Wiring up the second slave is straight forward a top and bottom loom with 4 and 3 wires respectively. No need to connect a temperature sensor..

Attached print screen of my current bms diagnostics programme. As you can see slave 2 has an fault due to the missing temp sensors readings are also 4300 +/-


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## mpobor (Jul 9, 2018)

where can i find more pics and info on the 12s conv.? 

and where to find more on this bms rev.eng.?


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## boekel (Nov 10, 2010)

mpobor said:


> where can i find more pics and info on the 12s conv.?
> 
> and where to find more on this bms rev.eng.?


Ah yeah this f... forum 'update' threw out all my pictures 

here they are:
http://boekel.nu/foto/17/2017-06_tesla_12s/

what is it you want to do?


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## brian_ (Feb 7, 2017)

Image links (which no longer work because they are not encrypted) converted to plain links:


boekel said:


> Sneak preview:
> 
> http://boekel.nu/foto/17/2017-02-tesla/2017-02-18 19.19.42.jpg
> 
> ...





boekel said:


> http://boekel.nu/foto/17/2017-02-tesla/2017-03-02 20.45.36.jpg
> 
> http://boekel.nu/foto/17/2017-02-tesla/2017-03-03 13.54.23.jpg
> 
> ...





boekel said:


> This is my route:
> 
> http://boekel.nu/foto/17/2017-02-tesla/Tesla module 12s modificatie-Model.jpg


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## mpobor (Jul 9, 2018)

boekel said:


> mpobor said:
> 
> 
> > where can i find more pics and info on the 12s conv.?
> ...


A conversion with 8 Tesla modules and the big drive unit from Tesla... 
I can't afford and I don't need 85kwh.. 

Do you make this kind of transformation? I'm in EU and I have a good contact for module at a fair price..but I would like to have someone that can do a solid conversion.. I can try but I'm not an electrician.


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## mpobor (Jul 9, 2018)

brian_ said:


> Image links (which no longer work because they are not encrypted) converted to plain links:
> 
> 
> boekel said:
> ...




.nu what country is this? Do you make the conversion for your self or you can do it to a third party?


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## brian_ (Feb 7, 2017)

mpobor said:


> .nu what country is this? Do you make the conversion for your self or you can do it to a third party?


These questions are for boekel; I just re-posted his posts with the links modified so that you can see his images.


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## mpobor (Jul 9, 2018)

brian_ said:


> mpobor said:
> 
> 
> > .nu what country is this? Do you make the conversion for your self or you can do it to a third party?
> ...


 Thank you Brian!


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## boekel (Nov 10, 2010)

mpobor said:


> A conversion with 8 Tesla modules and the big drive unit from Tesla...
> I can't afford and I don't need 85kwh..
> 
> Do you make this kind of transformation? I'm in EU and I have a good contact for module at a fair price..but I would like to have someone that can do a solid conversion.. I can try but I'm not an electrician.


Yes I can do the conversion.
No I don't recommend it for use with a big drive unit. Busbar size and new connections get too small for this.
Big drive unit also works with 14 modules, probably even less, but I don't know what's the lower limit. It would limit top speed / end of acceleration speed.

Considering the conversion cost about €250 per unit...and you need to arrange bms (extra tesla modules or custom bms), I'd save the money and buy some extra modules.

If you don't have place for the modules, consider using other batteries like:
-Nissan Leaf 40kWh pack
-Chevy Bolt (Volt EV in europe?) 60kWh
-Kia Soul 30kWh
-??

these are usually cheaper than Tesla modules, easier to place into car (except for the Bolt probably(, less explosive, lower internal resistance (more percormance).


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## brian_ (Feb 7, 2017)

boekel said:


> -Chevy Bolt (Volt EV in europe?) 60kWh
> ...
> these are usually cheaper than Tesla modules, easier to place into car (except for the Bolt probably(, less explosive, lower internal resistance (more percormance).


The Bolt is apparently called the Opel Ampera-e in Europe (naming based on the Opel Ampera, which was the continental European version of the Chevrolet Volt plug-in hybrid).

The Bolt pack is huge, and the modules need a "cold plate" thermal management system for full performance, but the size seems manageable:
10s3p module

Battery Rated Capacity: 5.94kwh
Nominal: 37V 160AH
Length 17" 
Width 13.5" 
Height 5"
Weight 65 lbs

8s3p module

Battery Rated Capacity: 4.75kwh
Nominal: 29.6V 160AH
Length 15" 
Width 13.5" 
Height 5"
Weight 52 lbs
I assume there are eight 10s modules plus two 8s modules in the Bolt pack.
(from the thread 2017 Chevy BOLT Battery quick tare down)


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## mpobor (Jul 9, 2018)

boekel said:


> mpobor said:
> 
> 
> > A conversion with 8 Tesla modules and the big drive unit from Tesla...
> ...




Got it.. Pretty clear.. I know for sure that chevy volt battery even if is very small and actually not that light like Teslas battery.. They can give high discharge rate and it can run the big drive unit at its best. 

Do you recommend the smaller drive unit for Tesla? Maybe it will be less powerful but maybe in a light car can gives the right performance and a better milage when driven smooth? .. What do you think?


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## mpobor (Jul 9, 2018)

BTW in EU is very hard to find used ev battery... I just found a good contact for Teslas.. The others are rarer and to me looks heavier and pricy as much as Teslas...
I will take you suggestion seriously and think about it in any case


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