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Discussion Starter #1
The i3 really grabbed my attention because the chassis is built out of a strong carbon fiber reinforced plastic that weights 1/2 the weight of steel. They know what I have known for a long time now; less weight requires less energy to move it. I have done everything that I know how to reduce weight in my own car. Every component has weight and almost everything can be made lighter. Many people have the idea that weight does not matter because the car is rolling on wheels. Every good engineer knows that the opposite is true; the car can be built light with aluminum, carbon fiber, or Kevlar. The battery and motor should also be as light as possible. Batteries with the highest energy density will reduce weight, reduce charge time, and extend range. I like many aspects of the BMW i3 but, the price is too heavy for me. We also need a car that we can afford. This last point is why I think that the Chevy Bolt will be a winner with a longer range and a lower price tag.
 

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Discussion Starter #3 (Edited)
Although the chassis is aluminium.

BMW had or, has a partnership with SGL Group to manufacture the carbon fiber chassis. The i3 has a curb weight of 3,124 lbs. Aluminum would be a good material but, I have not read that BMW has an aluminum chassis for the i3 or the i8. The M5 Series does have an aluminum chassis. Google search "BMW i3 carbon fiber"

What I find interesting about this is that my own car weights approx. 2600 lbs and goes 62 miles in a mixed driving using a 16.8Kw battery. It makes me wonder what I did right. However, the BMW has 150Hp and my little car runs on 73Hp or Hamster power.
 

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Discussion Starter #5 (Edited)
@satronev This will be highly illuminating i3 Teardown

BMW use aluminium for the flat battery and drivetrain, and the CFRP builds the passenger cell on top.
CFRP = Carbon Fiber Reinforced Polymer. Just wanted to clarify this.

Side note: I have been working with composites to build aircraft. Most people are horrified by them or, by anything that looks like plastic. I recently replaced the hood of my own electric car with lightweight carbon fiber and fiberglass composite. So, you can see that I am really onboard with the concept of weight reduction and lightweight materials. The carbon hood is not so out of place since the car is a Saturn SC2 with fiber plastic body. I am always comparing the best technology out there with the specs of my car to see if I should have spent $42,000. to buy verses the $18,000 to convert.
 

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SGL only make the fibre spools, its formed in Leipzig. The Quandts' made a large investment in the SGL CFRP process specifically for the i3 and future BMWs - they are building a new factory next to the current one at Moses Lake to meet future demand.

Both BMW and SGL refer to the product as CFRP...
 

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Discussion Starter #7
SGL only make the fibre spools, its formed in Leipzig. The Quandts' made a large investment in the SGL CFRP process specifically for the i3 and future BMWs - they are building a new factory next to the current one at Moses Lake to meet future demand.

Both BMW and SGL refer to the product as CFRP...
Good info. Thanks Jack. What do you think about the possibility of recycling the material or, are huge CFRP landfills in our future?
 

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Nearly all recyclable, the offcuts from forming are used in the dashboard - so there is reduced waste in production too. Its also possible to repair the CFRP cell where a traditional vehicle might be declared a total loss, and it loses no structural performance.
 

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Does the i3 have any steel at all? I would expect the steering and suspension system to be steel.
 

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Does the i3 have any steel at all? I would expect the steering and suspension system to be steel.
The springs should be steel. Wheel hubs and lug bolts should be steel. The shock absorbers probably have some steel.

I would expect most of the suspension to be aluminium. Even my 1990 535i had some aluminium suspension components.
 

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Nearly all recyclable, the offcuts from forming are used in the dashboard - so there is reduced waste in production too. Its also possible to repair the CFRP cell where a traditional vehicle might be declared a total loss, and it loses no structural performance.
I saw somewhere that the roof panel was also made of the offcuts as it's not structural that would make sense.(y)
 

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Nearly all recyclable, the offcuts from forming are used in the dashboard - so there is reduced waste in production too. Its also possible to repair the CFRP cell where a traditional vehicle might be declared a total loss, and it loses no structural performance.
How do you repair it? I've seen glider repairs and they were quite a pain to do and added weight.
 

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How do you repair it? I've seen glider repairs and they were quite a pain to do and added weight.
I don't think you do, I think you replace the panels that are damaged and if it's the shell itself there are joints at strategic places so you just cut the whole section out and glue in a new section, it's easy when you have the right tools/facilities.

It seems that the ease at which it can be repaired is reflected in the insurance prices, if it was hard/expensive to repair premiums would be much higher.
 

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How do you repair it?
When the i3 was launched I was taken to the BMW showroom in Park Lane to discuss the technical aspects of the i3 and I was told that the life cell can only be repaired in one place in the UK... I don't know if that has changed.
 

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I was told that the life cell can only be repaired in one place in the UK
Can be repaired at any i agent workshop, with appropriate repair kit (CFRP strips and bonding agent)

There is no good video or picture for but should any part of the CFRP shell is damaged it can be repaired by putting another CFRP repair pack over the top with a specifically designed bonding agent. Repairs such as this do no damage the integrity of the CFRP and a much cheaper than an equivalent repair to a conventional vehicle if such a repair was even possible.

However, this comes with a massive but. Whilst the CFRP is easy and cheap to repair, should you have been in an accident that damages the CFRP you will have quite likely had a very serious incident indeed, one that if you have walked away from the CFRP has done its job but the car would be damaged beyond economic repair. So it might not be worth repairing at all.
 
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