doug

http://www.autobloggreen.com/2007/04...t-wont-be-met/

Pretty big news.

doug

The car will weigh an additional "several hundred pounds!" I'm less concerned about how this affects the range, and more concerned about how this affects the acceleration and handling.

DDB

EV buyers know that they'll be getting something close to what Tesla claimed from the beginning. And I think they won't have a problem with the range, especially since 250 to 200 isn't that big of difference. My question is, will they meet their target date for production?

__________________
Dave

'05 Passat powered by Biodiesel
'54 Corvette

doug

Again, the range doesn't concern me. But how much exactly is several hundred lbs. Could that mean 500lbs? If so that's 20% of the originally estimated 2500lbs. That would mean a 0 to 60 time of closer to 5 seconds than 4. and handling that's less nimble.

tonybelding

According to Martin Eberhard, the additional weight is "a couple hundred pounds".* It wasn't any one big thing, it was about thirty little things that added up.* I've seen a long laundry list of changes including, but not limited to: a bigger coolant pump, stronger mounting brackets for the motor, the whole redesigned transmission, changes to the motor housing, changes to the ESS, and even things like improved stereo speakers and door latches.* Then as the weight crept upwards, it was necessary to go back and beef up the suspension and brakes to handle it.

Acceleration shouldn't be negatively impacted due to improvements in the power train.* Cornering will be affected, you can't get around the laws of physics -- but it'll still be a lighter weight car than, for example, my Esprit V8.

I have been reading about this for a couple of days on the forum for Tesla buyers, but didn't want to say anything until the news became public.* (Also I didn't actually get my letter until this morning.)* It's obviously disappointing. So far I haven't heard from any buyers who consider the range reduction a deal breaker.

tonybelding

While I'm on the subject. . .* * I did my own analysis based on my own needs for the car.* The longest trip I make on a semi-regular basis is from my home to Waco Texas and back.* It's 68 miles, a pretty good road, there are no big hills to climb.* Assuming I have no good opportunity to charge up in Waco. . .* *That's a 136 mile round trip.* I have to add a comfortable margin to that, so I can drive around town, possibly take some short side trips, or drive a little faster maybe.* So I arbitrarily added 20 miles to my requirement.* Now I need a 156 mile range to make this trip with confidence.

The battery pack degrades with time and usage, and we can assume it's due for replacement when it gets to 80% of the original capacity.* With a range of 200 miles when new, that would be down to about 160 miles before the end of its service life.* So. . .* *Even as the battery ages and degrades, it should still just about handle my trip to Waco and back -- but we're starting to cut it close.* If the range were reduced any further, I would have to start reconsidering my options.

Fortunately, I don't think it's going below 200 miles.* Tesla seem very confident that they can promise 200 EPA highway miles "or better".* According to the letter:

We continue to drive engineering improvements to increase range, and explore options that would allow you to choose between increased range and enhanced performance.* There are still some unknowns and variables that will become known as we develop and test our VP cars, so we have chosen to communicate a floor of 200 miles and strive for upward revisions in the future.

Also, some have noted that when the ESS comes due for replacement, it will be surprising if the new ones don't bring in better technology and longer ranges. So for buyers this may only be a temporary setback.

Iz

tonybelding: The ESS replacement in 5 years may be something other than Lithium-Ion. If EEStor can deliver on their ultra-capacitor and if it can be adapted to the Roadster, the temporary setback might not be so bad.

tonybelding

That would be a pretty large adaptation. . . The whole ESS and PEM would have to be replaced with something completely different. Not saying it can't be done, we'll just have to wait and see how it goes with EEStor. If they produce something miraculous, somebody will find a way to get it into the car. :)

I'd be amazed if there aren't significant improvements after five years (in my case that's six years from now -- my delivery date is still over a year away) that can be incorporated into the Roadster, even with li-ion technology. I believe 3.6 Ah li-ion cells are just now becoming available. Even moving to those would increase range from 200+ to 325+ miles. That's about the most conservative scenario that I can possibly imagine. There is also going to be a lot of work on improving their durability and service life. The first battery swap just might be the last one it ever needs.

Iz

That 125 mile range increase would be a nice improvement. The 3.6 Ah li-ion appears promising. It would be wise for Tesla engineers to plan this in WhiteStar.