Weight Reduction

AC1K said:

the Model S is a tank when it comes to weight, if you can lighten the vehicle you can probably get much more range out of it.

How much reduction in mass do you think swapping all body panels to carbon fiber would yield?

Click to expand...

I don't know, but I do know how much other stuff I could buy for that much money.

AC1K said:

the Model S is a tank when it comes to weight, if you can lighten the vehicle you can probably get much more range out of it.

How much reduction in mass do you think swapping all body panels to carbon fiber would yield?

Click to expand...

If you were to reduce its weight in some significant way, acceleration would improve most, with negligible improvement in range. So CF panels would be very costly for no real gain.

However, if you could reduce its Cd / CDa / Frontal area, you would see a more notable improvement in range.


Here's a few other things you could consider :-

• Driving 5mph to 10mph slower on a highway (could yield 5 to 15%),
• Turning down the Air Con (up to +10% or so, depending on temp diff etc),
• skinnier tyres (3-5%),
• Lower rolling resistance tyres (10%+),
• fairing in the rear wheels (3-5%)
• removing door mirrors (maybe 4%+)
• … and many more.


How about covering the entire bodywork in golf-ball dimples ?!! … good old mythbusters tried this and had a remarkably good 11% result for the same highway speed …. Would look kinda ugly though

AC1K said:

the Model S is a tank when it comes to weight, if you can lighten the vehicle you can probably get much more range out of it.

How much reduction in mass do you think swapping all body panels to carbon fiber would yield?

Click to expand...

Not much. Aluminum panels will be very light already.

Mythbusters clip where they get +11% range gain! But it ain't pretty ..

11% niższe spalanie paliwa - Mythbusters Golf Ball Car. - YouTube


Stick-on dimple wrap ! … but in this review, it didn’t work. Maybe the dimples were too small

Fastskinz Test Drive: Can a Golf Ball Covering Improve MPGs? - Popular Mechanics

PV4EV said:

Here's a few other things you could consider :-

Click to expand...

- Only drive downhill on sunny days with the wind at your back.

brianman said:

- Only drive downhill on sunny days with the wind at your back.

Click to expand...

Not forgetting to put a mini wind turbine on the back, and a layer of thin film solar PV all over the body too …

Maybe try out some transparent rear wheel fairings to prevent it looking like the ugly 2000-2006 Honda insight …. :biggrin:

How about replacing the body panels with something even more aerodynamic?

Weight reduction is probably most effective on unsprung weight like your wheels, brakes, and suspension. Additionally, it helps the most when the car is making speed transitions - like suburban 0-45-0 mph stop and go driving. I'd be itnerested in seeing if the car can be retrofitted with something like ceramic bearings to reduce the frictional coefficent of the drivetrain.

Like others have said, air resistance is the largest enemy when talking about cruising as it scales to the cube (I think) of velocity.

Wouldn't it be better to try to get lighter and bigger batteries to increase range?

AC1K said:

ideally super capacitors with the same energy density as gasoline, this would solve every problem, 1-5 min recharge time, rechargeable past 50,000 cycles, ultra high discharge speeds so you can use more powerful motors, stable, reliable, enough energy to go over 1000kms for range.

EDIT: capacitors have charging cycles of well over 100,000, it would last longer than your natural life.

Click to expand...

VERY NICE!

But when these super capacitors will be available for mass electric cars?

AC1K said:

ideally super capacitors with the same energy density as gasoline, this would solve every problem, 1-5 min recharge time, rechargeable past 50,000 cycles, ultra high discharge speeds so you can use more powerful motors, stable, reliable, enough energy to go over 1000kms for range.

EDIT: capacitors have charging cycles of well over 100,000, it would last longer than your natural life.

Click to expand...

Hint: Store energy in the form of magnetism, not electricity. Extraordinary energy density (look up the experiments). You just have to know how to control it. :wink:

AC1K said:

oil companies will kill this for sure

http://www.gizmag.com/nanoscale-supercapacitor/11297/

these super capacitors give 3000 wH/kg,
the article says that gas engines are 15% efficient tank to wheel giving it 1800 wh/kg

these capacitors will be better than gas/diesel/conventional chem batteries in every single possible way, faster refill/recharge, longer range, cheaper, cleaner, more power and even shape, its flexible so it can be any shape really, rectangle, round, cylindrical, whatever you need.

the only thing holding us back from this technology is greed and money, oil companies want to maintain their hold, everyone is poor and cant afford to spend the money on RD/infrastructure/etc,

Click to expand...

There's a lot of hand-waving away of serious engineering issues in this post.

Let's say the super-capacitor is perfect and charges 85kw in 5 minutes.
85 kilowatt hours = 306,000,000 joules
(306,000,000 joules) / (5 minutes) = 1020 kilowatts

That's 11.3x current supercharger capacity. Other than that, cables to support that are probably going to have to be much, much thicker that you want to deal with (I don't know what something with that capacity would look like).

Don't forget that the Tesla has one of the lowest CDs for any car built - .24

PV4EV said:

• skinnier tyres (3-5%),
• Lower rolling resistance tyres (10%+),
• fairing in the rear wheels (3-5%)
• removing door mirrors (maybe 4%+)

Click to expand...

Those are some good choices there, though I don't necessarily agree with the percentages. The huge wheels/tires are the biggest target:

Bang for the buck: Pizza tray aero wheel covers - someone already did that and found over 5% improvement at 60 mph: Aero wheels - Page 39

Combined with slighly narrower tires/wheels (will 18" wheels fit over the brakes?) with some good LRR tires and you'd be great. Fairing over the rear wheels is good as well, but you'd probably need narrower tires in the rear to make them really work well.

Mirrors are always a good bet, but tough to do cheaply as you need some decent cameras LCD displays to make up for them.

You might be able to taper the trunk line down more if you are willing to extend the trunk some. Tough to do and still be aesthetically pleasing unless you are good with body work. Maybe a spoiler like what you see on top-speed race cars, but any more downward taper on the trunk area and you will be increasing lift at the rear of the car unless you can also bring up the trunk floor up a similar amount.

Concur that CF body panels are a waste of time/money given that the existing ones are aluminum. Perhaps taping up the seams will help? Also often done on top-speed race cars.

neroden said:

Hint: Store energy in the form of magnetism, not electricity. Extraordinary energy density (look up the experiments). You just have to know how to control it. :wink:

Click to expand...

... and when you can control it use it to contain the anti-matter particles!

There is good research on magnetic energy storage -- it certainly will be cheaper than batteries, but I'm not sure about the energy density (kWh/kg). Lots of work being done in this area by, e.g. ABB.