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I wonder whose platform they'll use for the future under 50k dollar sedan...

WarpedOne

Supreme Premier
Aug 17, 2006
4,326
6,319
Slovenia, Europe
I see a problem here. When you are building a high performance car, cost isn't of high importance. You can use more exotic materials, like kevlar, aluminium chasie and such. Then the whole car weighs 800kg, with batteries 1200kg. Job well done.

But if you are building larger and cheaper car, cost becomes a limiting factor. Now you have to use cheaper, more mainstream materials and build a bigger car. That is going to be much havier. Say around 1200kg without batteries. Add current roadsters bat-pack and you have 1600kg bodywaight. And you have another goal - larger range. Same bat-pack, higher weight gives lower range, so you must use more batteris. Which is again more costly and again havier. Not good sittuation.

The only sollution that I can see is to use some other, lightier battery technoly. EEStor's ultracaps maybe?
 

danny

Administrator
Aug 15, 2006
1,386
445
California
another problem with the sedan is that it will undoubtfully be less aerodynamic which will
worsen the fuel economy or efficiency, or mpc.
 

dnavas

New Member
Aug 17, 2006
2
0
>But if you are building larger and cheaper car, cost becomes a limiting factor. Now you have to use
>cheaper, more mainstream materials and build a bigger car. That is going to be much havier.

I don't buy it.

My Saturn is certainly larger than the Roadster (though it is NOT a large car), but it weighs
about the same as the Roadster does. No fancy aluminum chassis. No carbon-fiber (though
dent-resistant panels are a definite plus for me).

Cars have become FAR too heavy in the last ten years.

-Dave
 

danny

Administrator
Aug 15, 2006
1,386
445
California
Yah, its all about the battery technology ;D, if they can double the capacity of the batteries, we should be seeing heavier electric cars around in no time ;)
 

tonybelding

Active Member
Aug 17, 2006
1,472
778
Hamilton, Texas
GreenSpeed said:
Yah, its all about the battery technology ;D, if they can double the capacity of the batteries, we should be seeing heavier electric cars around in no time ;)

I don't think so.  Even with double the capacity, it would still have a small fraction of the energy in a tank of gasoline.  And I've got to say I'm skeptical about doubling the energy density of Li-ion batteries.  Improvements in battery storage tend to come slowly, in small increments, and most chemists would say we're already pushing close to the natural limits.  I hope they are wrong, because doubling the capacity would help electric cars a LOT, but I'm not sure anybody should bet their business on that happening Real Soon Now.
 

Zoom

Member
Aug 18, 2006
6
1
Weight is one of the biggest mileage killers. We definitely need to get the whole auto industry to change over to composite body parts. Probably isn't going to happen in the next 10 years. Oh well. In the meantime, I'm holding out for the optimal chemical battery/ultracapacitor combination in the next 10 years to help reduce the weight of electric cars and/or extend their range. I know, forever the optimist. ;D
 

Zoom

Member
Aug 18, 2006
6
1
tonybelding said:
I don't think so. Even with double the capacity, it would still have a small fraction of the energy in a tank of gasoline.

True, but that's not the only factor at work here. Between the two, electric cars are (ballpark figure) roughly at least 3 times as efficient as our gas cars of today. So, while gasoline has about 10 times the stored energy as current lithium batteries, the gas powered engines/drive trains/etc. are only one third as efficient (meaning today gasoline stores usable energy of 10/3, or about 3.4 times that of batteries). So if battery energy was double, gasoline would only have a 1.7 times the usable energy equivalent. And considering our gas engines have had 100 years of development, whereas the lithium battery has only had 15 years(?), and ultracapacitors even less, I would bet that usable energy storage density in batteries will surpass gasoline quite soon.
 

tonybelding

Active Member
Aug 17, 2006
1,472
778
Hamilton, Texas
WarpedOne said:
My bet is on ultracapacitors.

Ultracapacitors sound great.  If they could even get close to the energy density of today's Li-ion batteries, they'd be the way to go -- rapid charging, never degrade or need replacing.  But is it really possible?  I've heard some people say high-density ultracaps are coming soon, and I've heard some others say it's a pipe dream in the same category with perpetual motion.  I don't know who to believe on that score.

The enthusiasm for ultracaps reminds me a little of the enthusiasm for flywheel storage a few years back.  "In just a few years," they said, "we'll have flywheels improved to the point where they're practical for electric cars."  Now it's a few years later and you don't hear about flywheels anymore, while the companies that were promoting them have switched to researching battery-electric vehicles.
 

asdar

Member
Aug 17, 2006
26
1
Even if the storage was much less, say 80% of the Tesla's, and the car only got 150-200 miles it would be worth it to have the ability to recharge in a couple minutes. 150 miles would handle almost all commuting needs, and if it didn't then you charge it up.

Zero maintenance and a near infinite life would be a huge bonus as well.

All the same capacitors have been around for a hundred years, adding the word Ultra doesn't change the basic concept. They do appear to have made a huge breakthrough at MIT, but I'm not holding my breath until I see a single working prototype, the way Tesla has.
 

tonybelding

Active Member
Aug 17, 2006
1,472
778
Hamilton, Texas
WarpedOne said:
But if you are building larger and cheaper car, cost becomes a limiting factor. Now you have to use cheaper, more mainstream materials and build a bigger car. That is going to be much havier. Say around 1200kg without batteries. Add current roadsters bat-pack and you have 1600kg bodywaight. And you have another goal - larger range. Same bat-pack, higher weight gives lower range, so you must use more batteris. Which is again more costly and again havier. Not good sittuation.

At one of their presentations, a representative from Tesla Motors said the "White Star" sedan is likely to use the same kind of extruded-aluminum chassis.  That's not only because of weight, but it works well in a low-volume production vehicle.  He said if you stamp the chassis out of steel, getting machinery set up for that is so expensive you'd have to build 100,000 cars for it to make financial sense.

Plus, they have an established relationship with Lotus, and Lotus have got this: http://www.gglotus.org/ggrace/vva-chassis/vva-chassis.htm
 

Future

Member
Mar 13, 2007
11
1
WarpedOne said:
I see a problem here. When you are building a high performance car, cost isn't of high importance. You can use more exotic materials, like kevlar, aluminium chasie and such. Then the whole car weighs 800kg, with batteries 1200kg. Job well done.

But if you are building larger and cheaper car, cost becomes a limiting factor. Now you have to use cheaper, more mainstream materials and build a bigger car. That is going to be much havier. Say around 1200kg without batteries. Add current roadsters bat-pack and you have 1600kg bodywaight. And you have another goal - larger range. Same bat-pack, higher weight gives lower range, so you must use more batteris. Which is again more costly and again havier. Not good sittuation.

The only sollution that I can see is to use some other, lightier battery technoly. EEStor's ultracaps maybe?

EEStor sounds like a great product! I realy hope that they deliver on their promises. If they do, then we could soon have EVs that outperform ICE cars in every way! (performance, looks, range, fill-up time, and efficency!)

There are only two things that concern me about EEStor's product.

1.) How much does it cost?
2.) Is it real? Is this all just vaporware?

Hopefully they will pull back the curtain on their mysterious ultracap soon :-\
 

WarpedOne

Supreme Premier
Aug 17, 2006
4,326
6,319
Slovenia, Europe
EEStor is still a mistery...

>> (performance, looks, range, fill-up time, and efficency!)

Well, fill-up times won't go away. It is not a battery-tech that is limiting them but energy distribution.
10-minute capability is irrelevant when you only have 10kW (tipical home) connection. Even large factory connections in megawatt range will only suffice for filling-up **one** car in 10-20 minutes.

The best way is to just start thinking/operating on new terms. Instead of driving until batteries are empty and then waiting for them to fill up you plug it in the evening and unplug it in the morning. In this way fill-up time is practicaly reduced into few seconds of your time. It doesn't metter if it took one or five hours in the night when you were asleep.
 

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