Tesla Motors

[JohnM]

6,831 lithium-ion cells

Range - 250 miles

top speed - 130 mph

Zero to 60mph and back to zero in 9 seconds

Fuel efficiency: 1 to 2 cents per mile

http://wired.com/news/wiredmag/0,71414-0.html?tw=wn_index_1

[polo_pro]

And all those batteries are going to have to be replaced in 2 or 3 years. Any estimate what it costs to replace 6000+ cells? I think the segway's Li-Ion have 60 cells, or is it 120 cells? And that car uses at least 50 times more?!

Figuring the cost has to be in the ball park of what Segway pays even with volume discouting, I'd guess the battery replacement costs would run between $20K annually!

[bystander]

6,831 lithium-ion cells

Range - 250 miles

top speed - 130 mph

Zero to 60mph and back to zero in 9 seconds

Fuel efficiency: 1 to 2 cents per mile

http://wired.com/news/wiredmag/0,71414-0.html?tw=wn_index_1From the 3rd page of the article:(When connected to a special 220-volt, 70-amp outlet, recharging takes about three and a half hours.)
JohnM, thanks for posting this. I'm not finding fault with your post, just some of the "facts" the author of the linked article is trying to pass along.

220 v x 70 a = 15.4 kw
15.4 kw x 3.5 h = ~54 kwh

The Tesla motors car will take around 54 kwh to "fill the tank"? At 15 cents per kwh, that's around $8 per "tank". If that ran the full 250 miles, that would be around 3.2 cents per mile. True, that's an improvement over a typical gasoline powered car, but it's not "Fuel efficiency: 1 to 2 cents per mile". What's wrong with the math? Or is it just a hype malfunction on the part of the press or PR department? By the way, if a car is rated for 80 mpg, and it costs $3 per gallon for fuel, that's 3.75 cents per mile.

There is a white paper at the Tesla motors website,

http://www.teslamotors.com/media/white_papers/Tesla%20White%20Paper_2006_07_19.pdf

That quotes an energy consumption of 110 wh per kilometer. That's equivalent to 177 wh per mile. 250 miles x 177 wh/m = 44.25 kwh. Can one assume the total battery capacity is around 44 kwh?

The white paper goes on to state that the charger is 86% efficient, so a 44 kwh capacity pack will take 51 kwh to charge completely.

51 kwh = 250 miles = $7.67 (@ 15 cents per kwh)
767 cents / 250 miles = 3.1 cents per mile

So I have to think that the real world cost is at least 3 cents per mile, not "1 to 2 cents per mile", unless you pay 5-10 cents per kwh of electricity. A large business might pay that little during off-peak hours, but an end-user consumer-type pays more due to fees and taxes.

Another interesting read in the white paper is that the car's range is estimated to be 200 miles per "tank", not 250. If you read the fine print on the website, it would seem that the term "250" mile range is actually "up to 250 miles".

That changes the math a bit:

200 miles x 177 wh/m = ~ 35 kwh

and 35 kwh / 86% charging efficiency = ~ 41 kwh need to go in for a full charge.

But the cost per mile doesn't change much:

41 kwh = 200 miles = $6.17 (@ 15 cents per kwh)
617 cents / 200 miles = 3.08 cents per mile

I'm not against electric cars per se, just figures that misrepresent the economics. My estimation of the pack capacity could be off a little, but I don't think it's off by a factor of two it would take to support the "1 to 2 cents" hype. It would be simpler if Tesla motors would state the capacity of the pack and the figure they are using for the cost of electricity. Ironically their website mentions they can hook people up to solar - either an on-site installation or using utility company "green power" (either of which turns out to cost a lot more per kwh).


Heh, heh, remember this old thread?

New battery tech -- 80% charge in 1 minute (http://forums.segwaychat.com/showthread.php?t=9456)

If your house has an electric oven and an electric water heater, you're already wired to handle this kind of high-capacity load. (just don't try to take a hot shower or bake anything while the car is charging! - lol)

[bystander]

And all those batteries are going to have to be replaced in 2 or 3 years. Any estimate what it costs to replace 6000+ cells? I think the segway's Li-Ion have 60 cells, or is it 120 cells? And that car uses at least 50 times more?!

Figuring the cost has to be in the ball park of what Segway pays even with volume discouting, I'd guess the battery replacement costs would run between $20K annually!I am under the impression that there are 184 cells in a pair of Saphion packs.

Costs per cell might not be comparable as Saphions may have a price premium over plain Lithium-ion. And part of the Saphion cost on the HT includes the cost of the charging and load-balancing circuits built into each pack.

More importantly, how good is the fire extinguishing system when the 6000+ plain L-ion cells start a thermal runaway event? The driver of a racecar wearing a fire retardant suit often survives a burning fuel fire, but how about molten Lithium? What kind of a suit do you need for that?

[polo_pro]

I am under the impression that there are 184 cells in a pair of Saphion packs.

More importantly, how good is the fire extinguishing system when the 6000+ plain L-ion cells start a thermal runaway event?

Even using 180 Li-Ion cells costing $1K as a basis for the estimation, I'm seeing annualized battery replacement costs in the $10K to $15K range. I realize these may not use Saphion technology, but they've gotta be considering using this technology. As you said, what happens when you have thermal run away or worse, a crash!

I wonder how fire departments are mitigating the risks now that every tenth car on the highway is a hybrid with nasty battery chemicals that spill out in an accident?

[citivolus]

And all those batteries are going to have to be replaced in 2 or 3 years. Any estimate what it costs to replace 6000+ cells? I think the segway's Li-Ion have 60 cells, or is it 120 cells?
Li-ion battery cells operate at a different voltage than the 1.2 V of NiMH and NiCad. Standard Li-ion cells are 3.6 volts each which gives only 20 cells for a 72 V package. My understanding is that the chemistry in the Saphion is slightly different and gives 3.2 or 3.4 V / cell, I don't recall the exact number but I know it is slightly lower than the usual 3.6. (It may be this voltage difference and charging requirements that partially accounts for the slow adoption.)

That said, I find the stated 6831 cells to be a laughable mistake. Consider the weight of each cell and the fact that the total voltage would be 24.5 kV... not likely.

[QuadSquad]

Just for your information where you live often times as a huge impact on your electricity rates. For instance in St. Louis we pay less than five cents per kilowatt hour. A little higher in the summertime a little less in the wintertime.

That would make electricity costs less than two cents per mile if you lived in St. Louis.


From the 3rd page of the article:
JohnM, thanks for posting this. I'm not finding fault with your post, just some of the "facts" the author of the linked article is trying to pass along.

220 v x 70 a = 15.4 kw
15.4 kw x 3.5 h = ~54 kwh

The Tesla motors car will take around 54 kwh to "fill the tank"? At 15 cents per kwh, that's around $8 per "tank". If that ran the full 250 miles, that would be around 3.2 cents per mile. True, that's an improvement over a typical gasoline powered car, but it's not "Fuel efficiency: 1 to 2 cents per mile". What's wrong with the math? Or is it just a hype malfunction on the part of the press or PR department? By the way, if a car is rated for 80 mpg, and it costs $3 per gallon for fuel, that's 3.75 cents per mile.

There is a white paper at the Tesla motors website,

http://www.teslamotors.com/media/white_papers/Tesla%20White%20Paper_2006_07_19.pdf

That quotes an energy consumption of 110 wh per kilometer. That's equivalent to 177 wh per mile. 250 miles x 177 wh/m = 44.25 kwh. Can one assume the total battery capacity is around 44 kwh?

The white paper goes on to state that the charger is 86% efficient, so a 44 kwh capacity pack will take 51 kwh to charge completely.

51 kwh = 250 miles = $7.67 (@ 15 cents per kwh)
767 cents / 250 miles = 3.1 cents per mile

So I have to think that the real world cost is at least 3 cents per mile, not "1 to 2 cents per mile", unless you pay 5-10 cents per kwh of electricity. A large business might pay that little during off-peak hours, but an end-user consumer-type pays more due to fees and taxes.

Another interesting read in the white paper is that the car's range is estimated to be 200 miles per "tank", not 250. If you read the fine print on the website, it would seem that the term "250" mile range is actually "up to 250 miles".

That changes the math a bit:

200 miles x 177 wh/m = ~ 35 kwh

and 35 kwh / 86% charging efficiency = ~ 41 kwh need to go in for a full charge.

But the cost per mile doesn't change much:

41 kwh = 200 miles = $6.17 (@ 15 cents per kwh)
617 cents / 200 miles = 3.08 cents per mile

I'm not against electric cars per se, just figures that misrepresent the economics. My estimation of the pack capacity could be off a little, but I don't think it's off by a factor of two it would take to support the "1 to 2 cents" hype. It would be simpler if Tesla motors would state the capacity of the pack and the figure they are using for the cost of electricity. Ironically their website mentions they can hook people up to solar - either an on-site installation or using utility company "green power" (either of which turns out to cost a lot more per kwh).


Heh, heh, remember this old thread?

New battery tech -- 80% charge in 1 minute (http://forums.segwaychat.com/showthread.php?t=9456)

If your house has an electric oven and an electric water heater, you're already wired to handle this kind of high-capacity load. (just don't try to take a hot shower or bake anything while the car is charging! - lol)

[byped]

51 kwh = 250 miles = $7.67 (@ 15 cents per kwh)
767 cents / 250 miles = 3.1 cents per mile



There's a blurb about it being the PG&E off-peak rate. Assumption being that you would plug in overnight.

[macgeek]

NOW, all we need is a Fuel cell that uses organic materials to charge it,
or a wind turbine (hey dean's house is perfect for one of these cars!)
And we HAVE something...

HOW much are one of these cars.. NO ONE IS TALKING PRICE

Jonathan

[bystander]

Li-ion battery cells operate at a different voltage than the 1.2 V of NiMH and NiCad. Standard Li-ion cells are 3.6 volts each which gives only 20 cells for a 72 V package. My understanding is that the chemistry in the Saphion is slightly different and gives 3.2 or 3.4 V / cell, I don't recall the exact number but I know it is slightly lower than the usual 3.6. (It may be this voltage difference and charging requirements that partially accounts for the slow adoption.)

That said, I find the stated 6831 cells to be a laughable mistake. Consider the weight of each cell and the fact that the total voltage would be 24.5 kV... not likely.The nominal voltage of each Saphion cell is around 3.2v. In a HT's battery pack, 4 cells are combined in parallel, and then 23 of the 4-unit groups are in series for a nominal pack voltage of about 75 v. Combining the cells in parallel gives the pack a higher "C" charge and discharge rate.

I would assume that Tesla motors is also paralleling some of the cells to get a fairly high amperage in/out of the pack.

[bystander]

Just for your information where you live often times as a huge impact on your electricity rates. For instance in St. Louis we pay less than five cents per kilowatt hour. A little higher in the summertime a little less in the wintertime.

That would make electricity costs less than two cents per mile if you lived in St. Louis.
There's a blurb about it being the PG&E off-peak rate. Assumption being that you would plug in overnight.
Thanks for the FYI.

I suppose there may be concern that if electric vehicles catch on in a big way, that electricity prices won't vary as much regionally, and may creep higher overall.