Model S range and efficiency info...

[saghost]

It looks like the "300 mile" Model S version will get an EPA 265 miles, if I understood the article correctly:

http://www.teslamotors.com/blog/mode...ency-and-range

They spend a lot of time talking about 320 miles, under the old 2 test version (pre-2008 EPA testing.)

It looks like the most efficient speed to drive a Model S without climate controls is ~22 mph.

If you assume a Leaf like ~85% battery utilization, that puts the EPA test consumption (miles per kWh of battery used) quite close to the Volt's. Very interesting...

[DonC]

Nissan marketing claims for the Leaf redux. This is very irritating. Using the unrealistic 2-Cycle EPA test for range, and then trying to CYA with the claim that you might get MORE or less, is simply BS. The discussion of the newer 5-cycle test is also misleading. AFAIK there is no 5-cycle test for EVs -- you just take the result from the 2-cycle test and reduce the range by 30%.

Real world with a 20 mile buffer -- you're not going to run the battery flat -- means that the actual range will be somewhere around 200 miles, give or take 30, mostly take.

The problem is that 200 miles wouldn't be that much better than 100 miles for me, and I suspect for most people (I'll say suspect but the data show this). Most of my driving in under 40 miles. Some is under 50 miles. And just about all is under 70 miles. After that we get into trip mode when we're easily at 250 miles a day. The 85 kWh pack is a tweener -- too large for 95% of the days and too little for 5% -- as opposed to the 40 kWh pack which will work for 93% of the days but not 7%. It will be interesting how many people go for it as opposed to the other options.

Also interesting that the article doesn't mention MPGe. I think the Roadster was assigned an MPGe of 119. That's very good. Since the article mentions that the Model S is almost as efficient as the Roadster, I was surprised not to see the MPGe number.

I simply doubt the .24 Cd number.

[cnicholson]

If the 265 mile range is on the same basis as the Volt's 35 mile range, then this seems quite good and entirely consistent with a real-world 300+ mile range (just as I tell people I get about 40 miles of EV range on the Volt).

I think the 85KwH Sig Performance version is VERY appealing. I very, very rarely drive more than 250 miles a day.

I am lucky to have room in my garage for an HOV-friendly commuter (Volt) and a luxury sedan. If I could have only one car, however, I think the Tesla would be very tempting.

The problem is that the one I would want for the all-in-one is $97K after rebates. The $50K entry model with 40 kWh wouldn't cut it in terms of range or performance/luxury. In that respect the marketing campaign is a bit of bait-and-switch, IMHO.

Finally, I'll bet the SOC window will be tighter on the small battery versions (need to assume more frequent near full discharge cycles). I wonder what the EPA range will be in it? Presumably a bit less than linear scaling based on battery capacity.

[DonC]

Finally, I'll bet the SOC window will be tighter on the small battery versions (need to assume more frequent near full discharge cycles). I wonder what the EPA range will be in it? Presumably a bit less than linear scaling based on battery capacity.

The usable SOC should be the same. You don't have larger cells just more of them. Performance aka acceleration times may change though.

I don't see a problem with cycle life. Over 12,000 miles you'd only do 120 cycles (based on my more pessimistic idea of the range not Tesla's). Moreover, these cells have a shelf life so time will take its toll before cycles do.

[saghost]

Finally, I'll bet the SOC window will be tighter on the small battery versions (need to assume more frequent near full discharge cycles). I wonder what the EPA range will be in it? Presumably a bit less than linear scaling based on battery capacity.

I don't know how valid they are, or where the gentleman got them, but in one of the comments off of the AutoblogGreen article that first pointed me there, a poster said this:

PeterScott
Bear in mind, that the bigger number is on the old EPA two-cycle test. This isn't the test the cars will be EPA certified with.

Calculating expectation for the other packs on old EPA 2 cycle:

85KWh - 320 miles
60KWh - 245 miles
40KWh - 170 miles


Calculating expecations for EPA 5 cycle numbers, the test the cars will actually be certified with.

85KWh - 265 miles
60KWh - 203 miles
40KWh - 141 miles

Note the numbers don't correlate 100% to packs size, as the smaller packs are lighter they gain some efficiency from that.

[kickincanada]

Just saw the Tesla S up close for first time. See my post on Canadian tread. Really, really nice car. I think Tesla made some good points in their blog and really I'm not getting too twisted into a pretzel over 2 cycle vs 5 cycle. There is no arguing Tesla has biggest battery pack and you can go long distances between charges as long as you keep the speed down to 50mph range (which is the speed limit on many secondary roads in Canada). With strategically placed fast chargers, really the Model S is the future and just as ground breaking as the Volt. Further comments in link below.

http://gm-volt.com/forum/showthread....478#post148478

[cnicholson]

The usable SOC should be the same. You don't have larger cells just more of them. Performance aka acceleration times may change though....moreover, these cells have a shelf life so time will take its toll before cycles do.

Good pont on shelf life being an important factor. I was thinking that if you assume that deep disharges will be infrequent, you could tolerate them and that the larger the battery, the less frequent the deep discharge cycle. Given small size, EREV like Volt need to assume virtually daily discharge cycles. if true, I was assuming that the larger packs could afford to go pretty deep in a "range challenge."

Especially for the Tesla which allows for VERY high discharge WOT acceleration, the 5-cycle test may prove too conservative for normal driving. I guess it depends on whether EPA tests with WOT hard acceleration or a normalized factor (like 0.3 average G's).

It seems like in highway driving, mass shouldn't matter very much.

[Epares]

Just saw the model S as well in NYC today, a very slick car... lots of interior room, my kids can fit comfortably in the back seat with plenty of room for luggage in the back as well as the front. I found it interesting also that it has its charger inherent in the car. If you plug into 110v it will charge 9 miles per hour, if it plugs into the volts j1772 connector it will charge 21 miles per hour, if you hardwire their proprietary plug into a 50 amp breaker it will charge 31 miles per hour ( according to the sales guy at Tesla ) .
One other thing that struck me was how clean everything was on the vehicle. I looked underneath the car and It was smooth with no wires or other anomalies. When I recently had my volt recalls done at the dealer I looked under the volt and saw quite a few exposed wire harnesses in the back of the vehicle underneath and I must say that it was a bit unnerving to think that all those wires are exposed to the elements... just a few random observations!...

[jomo25]

DonC, You seem pretty negative on Tesla and Elon. I won't begrudge as I'm assuming you have your reasons. But just as I think people need to have an open mind about the Volt, I think the same for the Tesla.

As for 2-cycle vs 5-cycle tests, I believe that the new standard test is a 5-cycle test. That only older cars that were certified under the 2-cycle could opt to do the 70% factor, or re-submit under the new 5-cycle test. But I'm no expert in this.

265 is only about 10% off from the claimed target. And given that they used the roadster's numbers (and tests) as a benchmark, given the new standard, that's pretty good. And depending on your drive style, 300 is very possible. (Just as I can get 40+ regularly out of my Volt, even though its officially 35 or so.)

I'm looking forward to the Model S. Not just as a potential purchaser. But as a believer in the EV movement. I think it presents another viable alternative. It will be great to have another choice for another segment or other drive situations. The Volt is one great solution to the movement away from petroleum-fueled vehicles. But it doesn't (and shouldn't) be the only one. The Leaf and FFE present another. And the Model S presents yet another type of solution.

[Jedi2155]

Tesla cells are basically laptop battery cells from Panasonic. The Volt's and most other EV's uses purpose built automotive grade lithium ion cells that can withstand the cycle life much better than the Tesla's. I do not expect the Tesla battery to last anywhere near as long as the Volt's or the Leaf's however since the range is much longer, I don't expect to hit the energy limitations anywhere near as often as you would on a Volt or Leaf. Due to that, I am still considering the Tesla vs. Volt 2.0 in my personal future.