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The Tesla Roadster - Electric Car



  • terry92270terry92270 Posts: 1,247
    "Good is not the enemy of perfect."

    Perfect quote! :P
  • You are correct in concluding that I feel (fairly strongly) that having a 50-100 mile electric driving range, with an efficient motor generator to provide extended driving range, will be the solution for the near term. Diesel is one option although I believe a flex-fuel option might be nice as an option. I admit that my preference is to be able to have a single vehicle that can satisfy most (if not all) of my specific driving needs.

    More power to those that can (and do) accept an electric only solution!
  • So, what is gained with this serial thing?

    If using an ICE to charge a battery to run an electric motor is somehow more efficient than driving the wheels with an ICE, why hasn't someone just used this as the primary system long ago? That is, regardless of the size of the battery, the power from the ICE/generator could be used to drive the motor?

    I tend to think that this
    ICE-->generator-->battery-->motor, chain can't lead to a gain in efficiency. I guess aside from the simplified trans, what else do you get?
    Can you really get by with a smaller engine if you want a serial to be able to run completely on gas when needed?
    Seems to defy my rudimentary knowledge of physics.
    Engineers out there?

    On edit: Ok, I just thought of one advantage. The battery can be charged while the car is stopped in idle.
  • tpetpe Posts: 2,342
    I tend to think that this
    ICE-->generator-->battery-->motor, chain can't lead to a gain in efficiency. I guess aside from the simplified trans, what else do you get?

    I used to feel the same way and maybe you are correct. The gain might come from the fact that when the engine kicked in to re-charge the batteries it would always run at its peak efficiency in terms of power generation per fuel usage. And once the battery was adequately re-charged the engine would shut down. This is not the case when the engine is driving the wheels and is operating throughout a wide range of power outputs that don't represent optimum conversion efficiency.

    While using this IC generator won't be as efficient as charging the batteries from the grid in day to day use this type of vehicle could be more efficient than a pure BEV. The reason being is that it could be significantly lighter. Replace the Tesla Roadster's 1,000 lb battery pack with a 300 lb battery pack and a 200 lb generator and you'll save 500 lbs of weight. For trips less than ~70 miles you will still be able to run as a pure BEV but will have saved energy by carrying around less weight. So it becomes somewhat of a trade-off that will vary by individual. If you are someone that rarely drives over 70 miles then you will actually save more energy by going this series hybrid route. If you take a lot of longer trips than the large battery pack would provide the greatest energy savings.
  • Thank you 'tpe'.

    You've done what seems to be an excellent summary of why this type of serial hybrid will probably be with us until such time as we have much better battery technology (e.g., less weight, better recharge, cheaper, more capacity) and a more comprehensive recharging infrastructure for extended road travel. This type of vehicle will allow most of us to drive in electric only mode for limited range commutes, but still allow us to have the freedom to take longer trips as needed without having to resort to having multiple cars or renting one.

    While I know that there are a lot of families that already have multiple cars, there are also a lot of people that are single with only one car or where the driving needs are so disparate between couples that sharing is not a comfortable option. Has anyone ever gone to a rental agency and been given a choice of vehicles to rent, where there was nothing available that they would have picked if given a choice? Has anyone ever said to their significant other, 'just pick out what you want since it's really going to be "YOUR" car'? For those that don't fall into these groups, great, for others, I'm sure you'll want what you want and will want it with as little compromise as possible.
  • terry92270terry92270 Posts: 1,247
    "Has anyone ever said to their significant other, 'just pick out what you want since it's really going to be 'YOUR' car'?"

    By any chance would you happen to be single? :P
  • tpetpe Posts: 2,342
    What's nice is that with these new high power density batteries a 300 lb battery pack could provide bursts of power that would allow for extreme performance. The Altairnano batteries have a power density of 4000 Watts per kg. That's around 560 kW in a 300 lb battery pack or 3 times what the Tesla Roadster's motor is rated at. And you probably wouldn't need more than a 70 hp engine to keep the batteries charged.
  • LOL, No, but I am one of those that doesn't share very well, so I want what I want with minimal compromise and our tastes are a bit different.
  • I hope there are options for we who don't want to spend the money or add the complication of a dual system

    I emailed Tesla as to what they anticipate the replacement cost of a battery to be. No reply so far.

    You know what I think the biggest possible killer to EV/HEV vehicles is? Liability. Suppose we go for awhile and people get the idea that there are health risks to being around that much EMF. Think of what happened with cell phones and breast implants. Doesn't even have to be valid. The sharks will circle.
  • tpetpe Posts: 2,342
    I'd guess the replacement cost for the Tesla battery pack is upwards of $40k. If BEVs become more common place this is where the biggest savings will occur because the price of this type of battery should drop significantly due to economies of scale. If ultra-capacitors ever live up to their hype it won't matter how much they cost because they will never wear out.
  • I've heard 40k bandied about. How is that arrived at?
    I don't know what their cost structure is, perhaps they lose money on every roadster made. But to do these small production runs using a purchased Lotus chassis and pretty much customizing the rest, has to be pretty expensive...if you are arriving at it by trying to back out costs from a total. I may ask Tesla again and this time be a "potential customer."

    MSRP on a Viper is $85k and up.
  • tpetpe Posts: 2,342
    The Tesla Roadster has a 50 kWh Li-ion battery pack. The few companies that sell these type of large format batteries quote prices of around $1k per kWh so when I said $40k for the Tesla pack I was being conservative. Tesla is not making much money, if any, on these initial cars, IMO, they are looking towards the future.

    I'd take the Tesla over the Viper in a heartbeat.
  • I've found that the Tesla pack contains a qty of 6800, Li- Ion 18650 cells. I've found these retail on the web for $7.25 ea for 2400mAh and $5.29 ea for 2200mAh. I don't know if tesla adds a lot of value to these in term of what they do and additional hardware they might apply. Also I don't know about the quality of the product I priced.

    Probably pretty safe to say that the pack costs at least $25k+...taking into consideration the quantity purchased.
  • rockyleerockylee Wyoming, MichiganPosts: 13,993
    ROCHESTER HILLS, Mich. — Electric-vehicle maker Tesla Motors used the opening of its new technical center here on Friday to announce the launch of Project WhiteStar. Its goal is to develop and produce a five-passenger high-performance sedan, expected to reach the market around 2009.

  • roland3roland3 Posts: 431
    ... A "Plug In Extended Range", taking half the battery weight and expense off a car like the Tesla and installing a lightweight genset, say 300 CC's (18 cubic inch) preferably Diesel, might be a good idea while we are waiting for that superconductive type breakthrough.
    ... So you are going on a trip in excess of 125 miles, well here is one thing the computers are not doing yet. At the start of this trip you run both batt and genset power, after two hours the genset should have added 40 to 50 percent charge. This should be near 200 mile range.
    ... This would also save quite a bit of time looking for a charging location any time you were stoped on these rare trips. Yes, it has it's limitations. What is that old saying about making all the people happy all of the time or that pursuit there of.
    ... Allright, you left the vehicle in long term parking for three days with the lights on and when you open the door your not quite sure if that's a reflection or the domelight is on, but the genset does crank; however this (with some sophisticated switching to not charge the batts at this time) will only run the car 15 MPH, but it gets you accross the street to a restaurant where you leave the genset run for an hour or more and viola 20 to 25 percent charge, might get you home if you live 30 or less miles away.
  • tpetpe Posts: 2,342
    That doesn't sound significantly different than what GM is planning with the Chevy Volt. The major difference is that the Volt will have a generator capable of actually re-charging the battery while you're driving, not just reducing its rate of depletion. In addition the Volt's generator would only kick in when the battery fell below a certain charge level. So regardless of the length of your trip you would always be using the minimum amount of fuel. GM says that battery technology isn't quite there yet. I think the people at Tesla would disagree. Now I agree that battery affordability isn't there yet, at least not for the mainstream even in this reduced battery pack configuration.
  • I guess it will depend on how the battery price and power play out as to how big the engines will be. 40 electric miles a day translates to 14,600 a year. Folks who could plug in at work could get up to an 80 mile commute on electric. Granted, we don't drive the same amount every day, but that would certainly make the ICE or diesel power mode pretty scantilly used for most folks. I bet some people who filled their tanks might have to worry because they use so little that the same gas might be in the tank long enough to turn bad and clog their system.

    Even the 50 mpg in gas mode would be a quarter to a half less fuel used for most.

    Not saying anything new here. I want to see these cars of various modes on the road and competing. Can't wait.
  • tpetpe Posts: 2,342
    I want to see these cars of various modes on the road and competing. Can't wait.

    I don't think the wait will be that long. Within a couple of years we should also have a lot more high mpg diesels to choose from and maybe even some diesel hybrids. So something for everyone. And when the government suggest higher CAFE the auto-manufacturers can respond, "hey, the vehicles are out there, now make people want them".
  • I keep hoping that GM comes around to acknowledging that the battery technology actually is here now, but using today's technology will require them to increase their planned battery capacity to allow for a longer EV range in order to have an acceptable number of recharge cycles to ensure a reasonable battery lifetime.
    By the time the car is ready for production, I feel confident that the price would also be at a reasonable point, perhaps even to allowing options for increased EV only range to keep price down for short range commuters but allow longer EV commute for others as they wish.

    In summary, I see no reason for GM to express any doubts about the possibility of the vehicle being made production ready and available sooner rather than later.
  • roland3roland3 Posts: 431
    ... I was origanally going to post this in "plug in hybrids" but the Tesla numbers: production date, weight, range, and price are facinating. Of course, who does not think of adding or taking away options, not everybody wants the ride/handling of a Zo/6 Corvette, or the power so most order a more domesticated beast.

    ... Any engineers out there have an idea of what would happen to the four second, zero to sixty, with half the peak load, taken away in batt size? Keep in mind that the car might be two to three hundred pounds lighter even with the little genset. Oh yeah, would have ten to fifteen thousand dollars to put a genset in the vehicle.
  • tpetpe Posts: 2,342
    .. Any engineers out there have an idea of what would happen to the four second, zero to sixty, with half the peak load, taken away in batt size?

    I'm by no means an expert on this but here's a couple things I do know. The Tesla has a 185 kW motor and a battery pack that is around 450 kg. Cut this in half and you have a 225 kg battery pack. Given that standard Li-ion batteries have a power density of around 1 kW per kg I think that the performance wouldn't suffer. There are newer battery technologies from companies like A123 Systems and Altairnano that supposedly have a big advantage when it comes to power density. They claim their batteries produce 3-4 kW per kg. So potentially a relatively small battery pack, say 100 kg, could supply a very powerful electric motor producing incredible performance, albeit with limited electric range. If I were rich I'd love to build a car with a 100 kW motor powering the front wheels and a 150 kW motor powering the rear. I'd install one of these new technology 100 kg battery packs and a 1 Liter diesel generator to keep it charged. Granted the generator would be running almost non-stop, which wouldn't make it much of an EV but it would have performance that probably exceeded that of a Viper while getting at least 30 mpg.
  • roland3roland3 Posts: 431
    ... Thankyou, Tpe, I still think of batteries as weight and cube, have enough keeping a working conversion mode, between my ears, for metric to inches (lol). The Tesla might be a real "tipping point" vehicle. Where else have you seen conversation about taking out power or range in an eletric before ???
  • Some sources are reporting the Tesla sedan will be built in NM.

    Also reporting that the price will be "at least $50k." How many green mercedes drivers are there who will accept the limitations? They say they want to build 10,000 units a year.

    All good I guess.
  • gagricegagrice San DiegoPosts: 30,619
    I would not consider one for my driving car. I would like a plug-in runabout for the short trips to the store. I don't think there is anything practical or useful about a $50k car with the inherent limitations of an electric vehicle.
  • tpetpe Posts: 2,342
    "at least $50k." How many green mercedes drivers are there who will accept the limitations?

    Other questions would be, are there any owners of $50k vehicles that never drive over 250 miles? How many people that can afford a $50k vehicle have more than one car? If there are those that fit into these categories then there are really no relevant limitations. And if this would be your only vehicle and you rarely make the 250+ mile trip there is always the option of renting on those occasions. And any limitations also need to be weighed against the convenience of foregoing the 30+ annual trips the average motorist makes to a filling station. What about the situation where you didn't plan on driving 250 miles but ended up needing to? Well I've been driving over 30 years and that's never come up. What about people that don't have access to an outlet for re-charging? Remember this is still a $50k vehicle. Not exactly aimed at the apartment dweller.

    So, IMO, a 250 range will be a non-factor for enough people that this car will still have a market. No it won't have the mass appeal of Camrys and Accords that sell 400k units but since they only plan on making 10k a year the fact that its appeal will be limited is also a non-factor. But to even sell that many this $50k EV will still have to offer comparable performance, comfort, and amenities to the other $50k vehicles that buyers have to choose from.
  • It was disappointing to hear that it was now to be "at least $50k" rather than the $40k that was bandied about earlier. "at least" implies that we are probably looking at closer to $60k.

    I am just guessing at the mindset of the average buyer in that categary, but I don't think they are much concerned with saving gas or the planet. Any drawback such as a range limitation could well be a deal breaker, whether it comes into play much or not. It's all about convenience, luxury, performance and status. Still, 10k is not all that many units..perhaps there are enough folks with the money and incling to move them. Certainly hollywood has a few elligible buyers. I have little doubt that the Tesla will be tricked out and perform well for its class. Perhaps the unique factor will spur buyers to go with it. The status thing..the I got stuff you don't thing.

    I guess at this point, I will be waiting for the Volt.
  • tpetpe Posts: 2,342
    I guess at this point, I will be waiting for the Volt.

    I agree. I think the Volt is the more logical next step on the way to pure EVs.
  • knightskyeknightskye Posts: 9
    Phoenix Motorcars is releasing, what, 5,000 of their SUTs next year? Those will be $45,000 - a lot less than the Roadster, and even lower than the White Star that hasn't been built yet. They said they're making an SUV, too. I wonder if the SUV will be under $40,000.

    For some reason, I see Phoenix doing a lot better in the beginning than Tesla. Whether it be their lower prices, or their awesome batteries that fully recharge in 10 minutes and have 9,000 life cycles. The car goes 130 miles, but they said something about an expansion pack that would allow the cars to go for about 250 miles.

    You guys are right, though. The cars, for a while, at least, won't be too affordable to the mass market. There will be some people pushed over the edge by the gasoline prices. The prices will come down once they mass-produce them, though. And then the Volt will come out. I wish they gave us a price estimate for the Volt, though.

    Tesla added weight to their car for safety and durability reasons, so now they just say, "Over 200 miles."
  • fordenvyfordenvy Posts: 72
    gas stations should employ recharging stations that use a 220 maybe instead of a 110, that way you can recharge in 1/2 hour instead of 6 hours, then the electric car can really become.
  • tpetpe Posts: 2,342
    If the Tesla's 50 kWh battery pack was almost fully discharged it would take around 7 hours to recharge from a 220V 30 amp outlet. There are special charging stations that can deliver power a lot faster. The Altairnano 35 kWh battery pack can be re-charged in 10 minutes at one of these high capacity charging stations. However I don't believe the batteries in the Tesla can accept a charge this fast even if it was available.

    So basically your roadtrips will be limited to ~200 miles. Probably not a big deal. If you consider this car to be an electric Dodge Viper then ask yourself, how many 200+ mile roadtrips do people make in Vipers? Probably not many. These types of cars are toys and not meant to be practical and shouldn't be judged from that perspective. But even as a toy the Tesla will be a valuable proof of concept testbed.
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