# BMW i3: ?The most advanced vehicle on the planet? taken apart and reverse-engineered



## PhantomPholly (Aug 20, 2008)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*

... and ugly, too...


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## twright (Aug 20, 2013)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*

I agree with the "ugly" comment. However, it's not ugly when you drive it. Great handling, nice power and I loved the adaptive cruise control.

If they made these things look like a 3 series, they wouldn't be able to build enough of them.


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## PhantomPholly (Aug 20, 2008)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*



twright said:


> I agree with the "ugly" comment. However, it's not ugly when you drive it. Great handling, nice power and I loved the adaptive cruise control.
> 
> If they made these things look like a 3 series, they wouldn't be able to build enough of them.


Yeah that's the part that bothers me. Why make them look geeky - are they doing it on purpose? They can make all-carbon frames now to get what looks like a normal 3 series, or even the 2 series, they wouldn't be able to keep one on the floor.

It's not just BMW, they all seem to be doing it except for Tesla.


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## favguy (May 2, 2008)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*

Yeah, I don't know why they have to be so damned ugly either, why not make them look cool and futuristic 

At least they got the i8 right. They can make a pretty car when they want to, this would have made a nice i3:


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## kennybobby (Aug 10, 2012)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*

It has a nice looking battery pack made up of 8 modules with 12 fairly large prismatic cells, 96s. He called it a 360 Volt pack and individual modules can be replaced with just 4 bolts. Each module has a somewhat simple looking BMU board with 12 resistors for using some sort of bleed-to-balance scheme, probably similar to what Tesla does if not a direct rip out of Elon's patent base... 

So they are more like the Leaf though with no active thermal control system.

These might make great DIY packs when they start hitting the salvage yards.

Edmund's is doing a long-term project on one.

22kwh pack, 18.8 usable, so about 60 Amp-hr cells.

Test ride got 270 W-hr/mile, weight was 2859 lbs. (~Jack's 10% rule of thumb)


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## PhantomPholly (Aug 20, 2008)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*

That is an awesome looking Bimmer!


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## eldis (Sep 3, 2013)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*



kennybobby said:


> It has a nice looking battery pack made up of 8 modules with 12 fairly large prismatic cells, 96s. He called it a 360 Volt pack and individual modules can be replaced with just 4 bolts. Each module has a somewhat simple looking BMU board with 12 resistors for using some sort of bleed-to-balance scheme, probably similar to what Tesla does if not a direct rip out of Elon's patent base...


The Tesla BMS is not really anything revolutionary - before photos of the Tesla BMS system were available, people talked about it like if there are some distilled unicorns, giving it magical powers 
At the end they are using a chip from TI, available to anyone since 2009 - we've been using it for our robotic car back in the university days. Six years after that, and this chip is still the best the industry has to offer (not a joke!)


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## PhantomPholly (Aug 20, 2008)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*



eldis said:


> The Tesla BMS is not really anything revolutionary - before photos of the Tesla BMS system were available, people talked about it like if there are some distilled unicorns, giving it magical powers
> At the end they are using a chip from TI, available to anyone since 2009 - we've been using it for our robotic car back in the university days. Six years after that, and this chip is still the best the industry has to offer (not a joke!)


Does the chip do the job well? Just sayin', if it ain't broke don't fix it...


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## eldis (Sep 3, 2013)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*



PhantomPholly said:


> Does the chip do the job well? Just sayin', if it ain't broke don't fix it...


Exactly. Texas did the job right the first time  Chevy Volt BMS is a joke compared to this.


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## kennybobby (Aug 10, 2012)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*

Tesla S is using the TI bq76PL536A chip which can handle 3 to 6 cells in series. The bleed resistance is 39 Ohms so only about 100mA current and it can bleed the pack of 0.9 to 1 kWh in a day.

Does TI make another chip to handle 12 in series--i can't read the board from the video...


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## eldis (Sep 3, 2013)

*Re: BMW i3: “The most advanced vehicle on the planet” taken apart and reverse-enginee*



kennybobby said:


> Tesla S is using the TI bq76PL536A chip which can handle 3 to 6 cells in series. The bleed resistance is 39 Ohms so only about 100mA current and it can bleed the pack of 0.9 to 1 kWh in a day.
> 
> Does TI make another chip to handle 12 in series--i can't read the board from the video...


I don't think that TI makes 12 cells version. Some other manufacturers do sell a higher cell count chips, but they are usually less advanced in terms of stacking capability (needs external optocouplers etc). TI has unique SPI current bus to communicate up and down the stack. Hard to say from this single picture how the BMW BMS is done. Could be double sided board, could be 12S chip.


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