Reverse engineering the i3 @ Munro

Hi guys,

if found this video through the German forum of Munro et al. reverse engineering (parts of) the i3:

http://www.forbes.com/video/3958851958001/

Regards, Steven

Stevei3 said:

Hi guys,

if found this video through the German forum of Munro et al. reverse engineering (parts of) the i3:

http://www.forbes.com/video/3958851958001/

Regards, Steven

Click to expand...

That video tell it all for me. Awesome report on what the i3 really is, simply makes me love mine that much more.

Thanks for posting.

Great video, I like the very last comment by Mr. Munro: "at 20,000 a year, this car is making money." If so, then the deal with CARB to emasculate the REx looks unnecessary as well as unfair....... If the i3 program is profitable in its own right, not needing to be subsidized by the ICE car lines, then there was no need to barter away their customers safety in exchange for carbon credits. That is, no need beyond profit seeking. We had hoped that the money from the carbon credits were going to support the i3 program, but perhaps they are just price supports for 7-series buyers after all.

Forbes.com posted a Joann Muller article on the teardown a couple of days after the video went up.

http://lifeforb.es/143rCKp

Definitely reinforces my decision to go with the i3.

<<<BMW’s battery is also unique compared to other electric vehicles. The 360-volt battery consists of eight independently controlled modules, each containing 12 cells. The advantage of BMW’s system is that when one cells goes bad, that module can be replaced, unlike in other EVs,>>

The VW e-Golf also uses a modular battery of 264 individual prismatic cells, which are integrated into 27 modules. What is unique about the i3 is the carbon fiber body in a volume car, although 6 majors are actively working on carbon fiber vehicles, including the VW XL1, Hyundai HED-9 Intrado, etc.

Although carbon fiber does save weight, it's much more expensive. VW in the e-golf has gone the route of ultra high strength fused steel panels to narrow the carbon weight gap by 50+ pounds, and their ownership in a carbon fiber company and the XL1 shows a strong interest but for now are playing it safe with the e-golf

Ron

cove3 said:

<<<BMW’s battery is also unique compared to other electric vehicles. The 360-volt battery consists of eight independently controlled modules, each containing 12 cells. The advantage of BMW’s system is that when one cells goes bad, that module can be replaced, unlike in other EVs,>>

The VW e-Golf also uses a modular battery of 264 individual prismatic cells, which are integrated into 27 modules. What is unique about the i3 is the carbon fiber body in a volume car, although 6 majors are actively working on carbon fiber vehicles, including the VW XL1, Hyundai HED-9 Intrado, etc.

Although carbon fiber does save weight, it's much more expensive. VW in the e-golf has gone the route of ultra high strength fused steel panels to narrow the carbon weight gap by 50+ pounds, and their ownership in a carbon fiber company and the XL1 shows a strong interest but for now are playing it safe with the e-golf

Ron

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And the Service manager at my BMW/VW dealership urged me to drive the e-golf; he said it is a dog compared to my car.

BUMWA said:

And the Service manager at my BMW/VW dealership urged me to drive the e-golf; he said it is a dog compared to my car.

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LOL. Quote of the day :mrgreen:

LOL What else would you expect him to say? The Golf was Motor Trend 2015 Car of the Year (Tesla in 2013) so you can hardly say it's a dog.

I drove both, own the e-Golf and can say he's dead wrong and most of the comparison reviews agree. For me, 7-10K cheaper, 2 full rear doors, 40% more cargo space, 4 levels of regen, 5 passengers, and a more traditional look (I know that's a minus to some, but you're not married to my wife) were the decision factors

Ron

I've had a Golf since 1994, it's been a good solid car. I'm not critical of it for what it is, but the differences between a steel ICE car converted to electric car and a ground-up re invention of a mass produced electric car are massive. Regardless of looks.

The advantages the e-Golf has are price and larger passenger capacity. The i3 takes most if not all of the rest of the cake.

Regarding looks, in these early days, electric vehicles need to stand out to be noticed by the market. The Leaf and the e-Golf don't do that, but the i3 and the model S both do that well.

Enjoy your VW, if it's anything like as pleasant and reliable as mine, it will be great.

<<<but the differences between a steel ICE car converted to electric car and a ground-up re invention of a mass produced electric car are massive.>..

I've read this argument numerous times, but except for the aluminum frame and carbon fiber body, I've never been able to figure out what these differences are.

Also. the 6th iteration 2015 Golf was redesigned with MQB architecture specifically to accommodate gas, diesel, LNG, electric and fuel cell drive trains, unlike the Leaf and others. So in one sense, it was a ground up re invention and certainly more than a conversion of an ICE platform to electric

Ron

cove3 said:

...4 levels of regen...

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Hm.. my i3 comes with unlimited number of regen levels. It brakes as hard or as little as I want without any selections to be made. I think how hard I want to brake and it does that. No buttons needed, just some old plain muscle memory in right foot.

You are right and I am wrong. i didn't drive the i3 long enough to be able to compare the two approaches and form a judgement. Now that I think about it, I'm wondering what factors led to VW choosing their approach over the i3. I'd have to drive both cars for a while. The 4 e-Golf settings give you a predictable regen without having to worry about how much feathering to use, pus you can set it to not regen at all. My wife, for example, would likely not like any regen.


Ron

cove3 said:

Now that I think about it, I'm wondering what factors led to VW choosing their approach over the i3

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It's a simple error in operational design.

If you start with a clean sheet, you get further innovation compared to starting with an existing design. I think you will find many examples of this in the i3 compared to de-iced models.

My i3 could use another stronger Regen mode. Once you get used to it it could be a bit more aggressive. Ideally one would have AWD, strong Regen and never need the brakes at all. Let the computer sort out which of the 4 wheels gets the most deceleration for handling enhancement. One pedal driving is the future......

<<It's a simple error in operational design.>>

I really doubt that. The Golf was a clean design, VW had an electric car a year before the e-golf, plus tear downs of all the other evs like the LEAF, as well as hybrids, so they would have not overlooked it, but rather studied it and made a conscious decision.

Ron

cove3 said:

<<It's a simple error in operational design.>>

I really doubt that. The Golf was a clean design, VW had an electric car a year before the e-golf, plus tear downs of all the other evs like the LEAF, as well as hybrids, so they would have not overlooked it, but rather studied it and made a conscious decision.

Ron

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I don't doubt that it was a concious decision. It is still poor design compared to driver modulated regen via the accelerator pedal.

The Golf is not a clean sheet design. They started with an existing body structure, construction methods, running gear and interior. After removing the ICE they then went about installing EV mechanicals, battery and control gear. I'm sure they have done a great job of it, but what they have is not a new ground up clean sheet design.

Of the current mainstream EV's I think only the Tesla and the i3 are in that category.

If you reconsider from scratch every design decision and material and engineering of the car, you come up with a completely new design that is more efficient.



It's not just about the weight, but the resulting differences are significant. VW: 3,090 lbs BMW: 2,635 lb

I'm not having a go at VW, I think they have done a great job on the e-Golf. It just is not in the same design class as the i3. I expect the differences to reduce as time goes on as the ideas and design process adopted by BMW become mainstream (which is the suggestion of this thread based on the reverse engineering)

The 3090lb weight is an error in early VW press releases which got worked into many reviews. I wrote VW that this couldn't be that low, and they finally corrected it when they announced the price to show curb weight of 3391lbs, a 750 lb disadvantage. But 200 of that is battery, another 150 or so is a bigger longer car, and the rest the aluminum frame carbon fiber body.

That aside, I don't think the charts support the argument that a ground up design resulted in any particular advantage over e-Golf which to a degree was also ground up in that the Golf platform was designed to take accommodate all 5 drive trains. No doubt some compromises were made but they must have been minor and would have been more than offset by the benefits of a common platform

The bigger battery, longer car, and use of high strength steel rather than aluminum/carbon fiber were all cost/appearance/function trade off decisions not related to the i3s being a ground up design. I have yet to see anything specific pointed out as to what these ground up design advantages are.

Ron

I think one of the major design advantages is staring you in the face in the epa ratings. The i3 is the most efficient production EV on sale. If you can't see that, then there is nothing about the i3 that will impress you. Have you noticed that the i3 is about 3 seconds faster to 100km/h, do you think that weight has a factor in that too?

Perhaps you should join an e-Golf forum? Golfs are great, but they are not BMW i3's.

LOL. The thread included statements that the i3 battery technology was unique and that the BMW service manager said the e-golf was a dog. Does this not make part of the thread a discussion of other vehicles and make it fair game for rebuttal?

As far as staring me in the face, I think you are mistaken. i3 27 kw/100 miles and 124 mpg vs egolf 29kw/100miles and 116 mpg constitutes a 2-7% difference and hardly seems material, considering the e-Golf weighs 28% more. Naturally, a lighter smaller sub compact car will get better mileage than a heavier compact car, all other things being equal. But a car that gets almost the same mpg despite weighing 28% or 750 lbs more is the more efficient car

Designing a bigger longer car with more cargo space and resultant heavier battery will result in a car weighing more and with longer 0-60. Designing that car with steel rather than carbon fiber will also result in a heavier car but it will also contribute to the car costing 9600 msrp less.

But these are not the result of ground up design advantages but rather design choices. I'm still waiting for the ground up design advantages for the i3.

As far as joining the e-Golf forum, I've been in both forums since mid 2014 when I decided to buy an ev, with my early research/test drives being the i3

Ron