By on October 26, 2010

Although the finished product works well enough, it’s also becoming increasingly apparent that the Volt missed two key project goals. GM’s oft-stated promise that the Volt would achieve 50 mpg in CS mode is history. The fact that GM felt the need to optimize the fuel consumption of the Volt by using premium (required, not just recommended) indicates how rather inefficiently its serial-predominant hybrid system works. It’s not a matter of ragging on about that; it’s just a surprise to those of us who argued endlessly which system (serial or parallel) was more efficient.

And now another long held Volt assumption is deflated. Based on GM statements made during the Volt’s long development, the universal understanding was that the Volt would use 8 Kwh of its 16 Kwh battery pack to achieve its 40 mile AER goal. It now turns out that 10.4 Kwh will be utilized. Sounds like small potatoes, but there are three not insignificant consequences as a result:

The very immediate and obvious one is that it will take more electricity to recharge the Volt. Given the losses of conversion at the charger and in the battery, it will probably take 12 to 13 Kwh of metered electricity to recharge a depleted Volt battery, so that the electric “fuel” costs in calculating the Volt’s operating costs need to be increased by some 20%-25%.

The more serious issue is that this deeper rate of discharge will stress the battery to a greater degree. Unsurprisingly, GM says, and presumably believes, that this is not a significant issue, and has confidence in the battery’s long-term health over its projected life. GM has said that the battery will lose between 10% to 30% of its capacity during the 8 years/100k miles of the warranty period. Whether the consumer or GM are hurt more if the Volt battery eventually turns out to age more rapidly is unknown, but it does increase the odds of there being an impact as a result of the deeper discharge.

Why was this change made? The Volt wouldn’t have met its nominal 40 mile AER without it. This and the Volt’s lower gasoline economy are interrelated. Both early Volt goals (40 mile AER on 8Kwh and 50 mpg in CS mode) were not met, because the Volt turned out to be less efficient in both modes.

Whether that’s the fault of excessive weight (some 3800 lbs), or less-than sterling aerodynamics (Cd: .28, same as a W124 Mercedes of 25 years ago), or other inefficiencies, is not known. Yes, the Volt works, just not as efficiently as hoped for, by both its maker and those that have followed its development.

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80 Comments on “Volt Misses Another Goal: Battery To Discharge Deeper Than Planned...”


  • avatar
    Blobinski

    Wow. The real world experience keeps moving the needle south.  Does it matter to the mainstream user?…maybe not.  Would this mean the charging time to a full battery charge for a 120V connection may exceed the time the vehicle is parked overnight, say on an average worknight?

    • 0 avatar
      Steven02

      Shouldn’t effect the charge overnight.  It will take longer, but most people have about 10-12 hours to charge the battery.  I think the projections on 110V was 6-8 hours earlier.

  • avatar
    TrailerTrash

    Paul,
    I see why this is important professionally.
    As a search for the truth…. what TTAC stands for …this is important.

    However, the street reality is this; the only things that matter are IF people buy it and that the government awarded public money for development and public money for incentive to buy it.
    These last two are what piss me off.
    Not the concept or that people buy it.

    • 0 avatar
      mcs

      Don’t forget the infrastructure costs. If your neighbors start blowing out transformers with their plug-ins, guess who’s going to help pay for them.

    • 0 avatar
      SVX pearlie

      I see very little “truth” here, to be honest. The fact is that the Volt gets 40 miles, and they project that the battery pack will be OK. So why all the sniping and snideness?

      All I see is that GM is being penalized for trying to be transparent with the media by providing details as to the Volt system. It’s like a huge “gotcha” game.

      I can imagine that, after this “debacle”, no carmaker will be nearly as forthcoming on details of any sort until the vehicle goes into production.

    • 0 avatar
      TrailerTrash

      SVX pearlie

      OK.
      Work with me here.

      Why is this car?
      Environmentally it is nothing if not average.
      Affordability takes it out of the reach of 75 percent of the buying public.
      Economical? Really?
      41 THOUSAND dollars. The next person who tells me I need to spend 41K to be economical will drive me to drink!

      Oh, wait…I am drinking. 

      Can you tell me why to buy THIS car over a diesel Golf or Jetta?
      If not using gas is the ONLY reason, I think you need to do more.
      I don’t have a phobia with gas stations.

      And you missed my entire point about the public funds being used for these purposes.
      You want to buy these things…bless you.
      Go for it.
      Just leave me to hell out of the process.

    • 0 avatar
      HerrKaLeun

      Can you tell me why to buy THIS car over a diesel Golf or Jetta?

      Because buying a new battery even every 5 years still is cheaper than keeping up with VW repair and maintenance bills?

    • 0 avatar
      SVX pearlie

      *BUY* a 1st Gen EV? Not on my life. Tech will get better and cheaper, so why pay more now, for what will clearly cost less and give more later.

      The only thing stupider than buying a Volt outright is buying a Leaf. A Leaf with a degraded / dead battery pack will be an awfully expensive grocery-getter / paperweight. Worst case, a Volt with a dead pack ends up running in CS mode all the time.

      OTOH, lease for $360 a month? $4k a year isn’t a bad number, given that my fuel cost would be almost nothing, and I don’t risk any depreciation or battery pack degradation.

    • 0 avatar
      HerrKaLeun

      Sure, the Volt also will be useful with degraded battery, unlike the Leaf. but what is the life of the IC? Since it is designed as an emergency generator, IT likely is not made to run 200,000 miles. Maybe that isn’t necessary. Assuming my battery seriously degrades after 10 years (what is the warranty and it conditions anyway?), getting 5 more years of life out of the car may be good enough.

    • 0 avatar
      jkross22

      @SVX Pearlie,
      “I see very little “truth” here, to be honest. The fact is that the Volt gets 40 miles, and they project that the battery pack will be OK. So why all the sniping and snideness?”
      You’re kidding, right?  GM makes an engineering claim that is not exactly true (how many claims on the Volt has GM made that turned out to be outright wrong?), and you’re saying Paul is sniping and being snide.
      GM is not being transparent and there is no gotcha game.  If GM is concerned about reasonable scrutiny, as they should, then they should be more focused on producing accurate data.  Seems like they’re either sloppy or just playing more of the same shell games that has people reviewing this stuff in the first place.
      No need to shoot the messenger.

       

      `

    • 0 avatar
      SVX pearlie

      The facts are the facts, yes.

      How they’re presented and editorialized is where bias comes in.

      Sometimes, TTAC comes off like Fox News.

    • 0 avatar
      ALB-MAN

      ^ obvious troll is obvious

    • 0 avatar
      Steven02

      I agree with SVX here.  GM is announcing that it is taking more battery power to move the car from point A to point B.  Automatically people question the battery life and say GM is failing to meet another goal.
      But, if you read the article about the Leaf and the miles on EV it gets in different driving conditions, it seems to be far less nit picky.  And there were cases that the Leaf would only get 62 miles on EV.
      At the lease price, many people will be able to try out the Volt.
      The infrastructure argument is bogus.  It applies to all EV’s, not just this one.  And if the transformers get blown, the electric company will have to pay to replace them.  Yes, everyone will be paying the electric company for that.  But if someone damages a gas station, who pays for that?  I don’t see your point there.
      Also, the public funding argument is pretty dumb as well.  Correct me if I am wrong, many companies have gotten public assistance in one form or another, involuntary assistance is what I am talking about.
       
      I didn’t vote on cash for clunkers.  I didn’t vote on tax abatements for manufactures.  I didn’t vote on rebates for fuel efficient hybrids.  I didn’t vote for rebates on EVs.  Yet, all of the manufactures benefited from all of these, or will do so in the near future.

  • avatar
    HerrKaLeun

    We learn again:
    - leasing is the better deal here and takes the technology risk away from the owner
    - like with all new technology, wait for the 2nd generation. Just compare a 1st gen Prius (sedan) to the 2nd generation. Except that Toyota already has the 3rd generation and is light years ahead.
     
    As far as the battery goes, I can imagine there will be chip-tuners unlocking all the 16 kWh to be able to drive 50 miles (for some months anyway). How does that compare to the Leaf, i mean what is the rated battery ratio to actually used?
     
    Another question what is the standby consumption of the charger after it is done charging? does it use 0.5 W like ENERGY STAR rated ones, or is is sucking 20 W all the time?
     
    has confidence in the battery’s long-term health over its projected life.

    When a manufacturer says that without telling me what the projected life is,that scares me. Of course the battery will live as long as it lives. the question is, will that be 15 years or 5? and what is the performance warranty? do they guarantee 80% capacity after 100,000 miles / 10 years? I mean technically the battery still works and is not replaced under warranty. My range is limited to 2 miles, but it still works…
     

    • 0 avatar
      SVX pearlie

      “How does it compare to the Leaf?”

      In the Volt case, we learn that GM is using 60-70% of the pack rather than the planned 50%.

      For the Leaf, nobody except Nissan really knows. Nissan plays their cards close to the vest, and only releases the positive information that they choose to reveal. For all we know, the Nissan uses 99% of its pack to get to 100+ miles, but they aren’t telling anyone.

      A good example of this is the 100+ mile “real world” round trip route that Nissan selected. It is a leisurely city-speed drive with no battery-sapping high-speed highway driving, and a 55-mph maximum speed limit that never was exceeded. I wonder how long it took Nissan to hunt that route out to ensure the Leaf would make it with some battery reserve.

      When the Leaf has the same level of scrutiny and independent real-world testing as the Volt, then we’ll know for sure. Heck, I’d even settle for some ham-fisted Motor Trend-type “testing” of the Leaf’s range.

    • 0 avatar
      HerrKaLeun

      There also is the question of efficiency. If I need 12 kWh to charge the 10 kWh usable battery when it is new. How many kWh do I need to put in to get 8 kWh out when the battery is old. Still 12 kWh? Maybe my usable capacity drops to 5 kWh over time. If I still need 10 or even 12 kWh to charge, my economics really get bad. Any battery specialists here?

    • 0 avatar
      Paul Niedermeyer

      Nissan has already stated that the Leaf will use 19.2 Kwh of its 24 Kwh battery. But that is comparing apples to oranges.
      One: the Volt will more often use its full EV range, since it has a shorter range. Nissan is basing its assumptions on drivers generally using substantially less than the full capacity per cycle.
      Two: the two companies use different batteries; they’re not the same chemistry and construction.The smaller the capacity of the battery, the more heavily it will be stressed per cycle. That’s also, in part, why the Volt uses liquid cooling, and the Leaf air cooling for their batteries.
      I’m not predicting that this change in the Volt’s battery will necessarily cause any problems with it; but it is a change worth noting, as I have done here.

    • 0 avatar
      Daanii2

      Any battery specialists here?

      I can’t answer all battery questions, but I can answer this one. If your battery gets old and only holds 5 kilowatt hours instead of the 12 it held when new, you will not need to put 12 kilowatt hours in to get the 5.

      Most charging systems lose between 10% and 20% of the electricity as heat during charging. So to put 12 kilowatt hours in your battery will cost you about 14 kilowatt hours at the meter. To put 5 kilowatt hours in will cost you about 6.

      Your other questions about batteries are good ones. But I don’t think anyone knows the answer. If they do, they are not telling.

      For example, I’ve been trying to find out about the battery performance in the Tesla Roadster. My bet is that the people who got the first Roadsters almost three years ago have lost over half their range.

      Anyone have any hard data on that? Or soft data? Or vicious rumors? I’m very curious.

  • avatar
    rudiger

    Does anyone know how deeply the batteries are discharged in competitor’s hybrids? I know that the original Honda Insight went pretty deep, resulting in great fuel mileage, but shortened battery life.

    • 0 avatar
      HerrKaLeun

      For the Prius it stays around 70-80%, which they claim is the optimum for the life of the battery. Even considering the first generation wasn’t so up to date, I haven’t heard of significant battery degradation. If nothing else, millions are on the road and many of those sure have seen more than 100,000 miles already, which we can’t say about too many EVs.
       
      Judging from our experience with laptops and cell phones, battery degradation is real. This might not matter for my 4 year old phone since it is obsolete anyway (or not). but a car has a much longer life.

    • 0 avatar
      SVX pearlie

      For the Prius, battery capacity isn’t the same issue as the Leaf or Volt. If the Prius goes from 2 miles to 1 mile, it’s not a big deal, as the primary mover is the gas engine.

      If the Leaf goes from 100 to 50, or the Volt goes from 40 to 20, that’s a much bigger problem for the owner. The half-range Leaf owner may no longer be able to commute back-and-forth without charging at work, or he may need a second car for those days which he wants to do an errand. The half-range Volt owner is now stuck with spending a lot more for gas than he had planned on.

  • avatar
    Steinweg

    That’s disappointing.
    But what’s creepy is that I was reading about the W124 yesterday and noted the 0.28 cD too, it’s good for a modern, it’s as good as a new Sonata. Stop following me. You wouldn’t think it given its trad three box look and relatively square everything, but I guess they honed those panel gaps and chose appropriate wheels and tires. Get away from my house. I’m not a big M-B fan and the W124 sedan is probably the newest Merc I’d ever want to buy, but the way they last it’s plenty new enough. I see you in the hedge there. Beat it!

    • 0 avatar
      SVX pearlie

      I’d be very curious to see what independent wind tunnel tests would calculate for real-world Cd. It’s the sort of thing that I wish Consumer Reports had the budget for.

    • 0 avatar
      Ooshley

      A 1935 Tatra T77A has a better Cd than just about anything on sale to the public since, but that doesn’t make the majority of last 75 years of car body shapes all terrible designs.
      Plus Cd means 3/5 of SFA for directly comparing the real-world aero-efficiency of cars, CdA which takes in to account frontal area is the truly important yard-stick.

    • 0 avatar
      JimC

      Cd is only half of the picture for wind resistance.  You need to multiply that by cross-section area…

    • 0 avatar
      benzaholic

      Still, props to the W124 for being ahead of its time while still very mass produced.
      You could pick them up used for 10 or 12 thousand dollars after several years, and they really did make outstanding long term daily drivers.

  • avatar
    SunnyvaleCA

    If the Volt could achieve 50 MPG in charge sustaining mode, then why even bother with the huge-capacity battery and plug-in?  Ditch the huge battery and recharging and instead go head-to-head with the Prius with a cheaper and simpler vehicle.  (Or the flip side argument:  Of course the Volt wasn’t going to get 50 MPG… otherwise Toyota wouldn’t have gone through all that effort just to achieve the same thing.)

    • 0 avatar
      Paul Niedermeyer

      I’m not getting your argument. The Volt project goal from the beginning was to build a better (first) plug-in hybrid, one that drove electrically for 40 miles and then got 50 mpg.

  • avatar
    Blobinski

    GM does it to themselves.  Releasing hopeful tidbits of info to the public and then having these claims be ‘un-truths’ in the end is so predictable for them. GM Guys..leave the horses in the barn longer and you won’t be stuck eating your reputation time and time again.

    The Asian companies, of which I have worked with for years, quite often never commit unless they are solid or they under-commit and then over-deliver…..

  • avatar
    John Horner

    GM never has figured out the under-promise, over-deliver way of doing things. With GM it is more over promise, get maybe sort-a close, then complain when people don’t bow down and worship.
     
     

  • avatar

    @svx pearlie
    Automotive sites that are worth anything exist to critique cars, not to be cheer leaders. I’m getting exactly the kind of stuff I want to know from this post. Furthermore, I don’t have any sense that Paul is going all Fox News on us. He’s giving us facts and analysis. Fox is more of a cheer leader to the conservatives and a trash talker to the Democrats.

  • avatar
    DenverMike

    How much does a replacement battery cost? $10,000? It could get damage by driver error, debris in the roadway or whatever. Theft recovery, perhaps.
    Will it cost more than the Volt used car value 2 years from now? What about at 100,001 miles? I guess I could drive it with a permanently dead battery but can I ditch the battery altogther at that point since it’s dead weight? Bypass circuitry?

    • 0 avatar
      Steven02

      Replacement costs isn’t documented yet, as it will likely go down before anyone actually needs a replacement.
       
      But, if the driver buys a car and accidentally damages it, that is what insurance is for.  If it isn’t an insurance thing, 100,000 mile warranty is what you have.  You can probably get an after market warranty or extended warranty if you want as well.

  • avatar
    Amendment X

    If my laptop battery is any indication of how crappy battery technology still is then GM is in big trouble.

    • 0 avatar
      gslippy

      Battery energy density is advancing, but not very quickly.  The popular notion that ‘technology gets cheaper over time’ doesn’t apply much to batteries, yet we hear it all the time.

      All EVs will suffer from this problem, proving again that EV popularity is driven mostly by politicians with greenies chirping in their ears, rather than consumers demanding such products.

      Battery research and manufacturing is exceptionally expensive, risky, and time-consuming to do.  The environmental impact of battery mfg is potentially high, which is why almost nobody in the US does it (the Volt’s cells are made in Korea).  Anyone investing in it could lose everything, as ‘success’ is measured both in the technology and the ability to sell it to someone – each very challenging.

      An interesting feature of the EV field is that [I think] nobody actually produces their own cells – all car mfrs are merely battery packagers.  This is unlike internal combustion engine development, and has the effect of forcing battery mfrs and car mfrs to engage in a strange kibuki dance in order to make a go of a product.  Things will improve once car mfrs take the plunge and actually build their own cells.

    • 0 avatar
      Daanii2

      Things will improve once car mfrs take the plunge and actually build their own cells.

      Maybe. But I don’t think so. Batteries have been around for 150 years. Over that time no one has made a success in the battery business. Gravestones litter the industry landscape. Even Edison spent a lot of time, sweat and money on battery technology, only to fall far short of what he sought and claimed.

      Interestingly, Magna wants to build a battery business. They hired Mike Reed to head up that new business, and appear to be throwing a fair amount of money at the problem. But Mike Reed ran two battery businesses into the ground already — Eagle Picher and Electro Energy — and I think will do the same at Magna.

    • 0 avatar
      musiccitymafia

      Didn’t Jaq Nasser go to a Battery firm for awhile after Ford? Cars and Batteries. But I think he left and is causing mischief somewhere else now (Bank One and then a bigger banking fish I think?)

      Speaking post Ford of course …. Is he just going where someone will hire him or is he leaving the dead ends.

    • 0 avatar
      Steven02

      You should be saying the same thing about the Prius, Leaf, and EV Focus that is coming out too.

  • avatar
    Amendment X

    On a side note, has anyone looked at the efficiency of an electric car with a built-in gasoline-to-electric generator, which would have the sole purpose of recharging while driving?
     
    It could be a tiny little engine and wouldn’t drive the wheels directly. The car would work sort of like a diesel-electric locomotive.
     
    Has anyone heard of a company looking into this concept? Any thoughts from engineers on its usability?

    • 0 avatar
      Brian P

      That is EXACTLY how the Volt works … with the exception that the Volt is capable of connecting the engine directly to the wheels in order to bypass the inefficiency of converting mechanical power to electricity to battery to electricity to mechanical power again, so it’s actually slightly *more* efficient than a pure series hybrid.
       
      That “tiny little engine” needs to be big enough to sustain the car’s average power demand when travelling at highway speed up a long hill. Undersizing the engine will result in more charge/discharge losses and will have poorer efficiency than a suitably sized engine.

    • 0 avatar
      Amendment X

      But it’s not EXACTLY how the Volt works. Does the Volt’s engine run while the car is running off battery? No.
       
      I’m talking about an electric car with a generator that would run all the time while driving, continuously recharging the battery.
       
      I wonder how many more miles per gallon GM could add to the Volt if there was a setting to run the engine in idle for the sole purpose of recharging the battery. The average consumer wouldn’t really understand how an “electric car” could have a gasoline motor running all the time, but it wouldn’t matter.
       
      I am picturing one of those TINY garage-type gas generators essentially shoehorned into a vehicle. Why not do that?

    • 0 avatar
      Daanii2

      Has anyone heard of a company looking into this concept?

      Our tiny electric car startup is building a proof-of-concept car that works that way. The problem is efficiency. That’s why no one else is trying it. Especially the big carmakers.

      We’ll see in about six months how well the concept works. On paper, it looks good.

    • 0 avatar
      John Horner

      Simply put, there is generally too much efficiency lost in converting from chemical to mechanical energy (the internal combustion engine), mechanical to electrical (the generator) and then back from electrical to mechanical energy (the electric drive motor). A conventional automotive power train converts directly from chemical (fuel) energy to mechanical energy.
      Perhaps there is a special case for long haul locomotives whereby they are able to make the energy conversion losses through reduced drive-line losses, but for automobiles I don’t think the math will ever work.
      Thermodynamics tells us that every energy conversion process inevitably entails losses.
       

    • 0 avatar
      Paul Niedermeyer

      John Horner,  Diesel-electric locomotives accept losses in exchange for traction control and reliability. Mechanical and hydraulic transmissions were used, especially in Germany, where efficiency is more important. And the German locomotives were tried in the US in the sixties, but they didn’t have the superb reliability of the American diesel-electric approach. American locomotives are expected to run months and years on end, with very little or no maintenance.
      It would be quite a challenge to build a mechanical clutch/transmission for a 6000hp locomotive with steel wheels, where slippage is a serious concern. Using electric motors allows for superb traction control during the critical start-up phase of a train.
      It wouldn’t surprise me though, to some day see a more efficient design be tried again for locomotives.

    • 0 avatar
      Daanii2

      Thermodynamics tells us that every energy conversion process inevitably entails losses.

      You’re thinking of heat engines. Thermodynamics doesn’t apply to conversions between electrical and mechanical energy. In generators and motors, you can limit losses to only a few percent.

      So although it’s not easy, you could have:

      – a heat engine getting over 50% efficiency changing chemical energy (in diesel) to mechanical energy,

      – a generator getting over 95% changing that mechanical energy to electrical energy, and

      – a motor getting over 95% changing that electrical energy to mechanical energy (at the wheels).

      A car with a system like that could get 80 miles per gallon.

    • 0 avatar
      thehomelessguy

      Back to the trains, they have made them a bit more effiecient and “hybrid” over the years. Most diesel electrics do run the wheel motors in reverse (as generators) like a hybrid to provide braking force and reduce the workload on the “real” brakes. However, traditionally, nothing was done with the power generated. It was simply routed to coils on top of the train and radiated away (there are basically giant electric heaters on top of most trains in the US).
      GE (they’ve advertised these on TV) now has diesel electrics with a crazy molten sodium (really really hot) battery that is able to store the energy from regenerative braking and actually does reduce emissions/increases fuel economy.

    • 0 avatar
      Morea

      You’re thinking of heat engines. Thermodynamics doesn’t apply to conversions between electrical and mechanical energy.

      Nope.  Thermodynamics applies to everything.  Heat engines are just the examples used in undergraduate text books.  That’s why they are the Laws of Thermodynamics and not the Suggestions of Thermodynamics.

    • 0 avatar
      Daanii2

      Thermodynamics applies to everything.

      You’re right that thermodynamics applies to everything. I should have been more careful in what I said.

      What I mean is this. The second law of thermodynamics describes the limits on efficiencies of heat engines. It is hard to get very much efficiency out of a heat engine. The most efficient that have been demonstrated are about 60%. Over 90% efficiency may well be impossible.

      The efficiency of generators and motors is limited mainly by heat losses due to i squared times R. Over 90% efficiency of these machines is not only possible, it has been demonstrated.

    • 0 avatar
      Steven02

      Amendment X,
      What would be the point of plugging the car in at that point?

  • avatar
    Beerboy12

    Personally I think they should have used diesel and not gas. Diesel engine produces much more torque for the revs and the motors are typically simpler and stronger than a gas motor therefore making a far better generator. Kind of like a diesel electric with a battery.

    • 0 avatar
      psarhjinian

      Torque doesn’t matter for a gen-set this small, and to get reasonable power from a diesel you need turbocharging and a much heavier block. On top of that, most hybrids run their engines at their most efficient state anyway and wouldn’t benefit from diesel’s efficiency at less than WOT.
       
      I think, but I’m not sure, that diesel fuel doesn’t have the same shelf-life that gasoline does. In something like the Volt that might be an issue. Total conjecture, though.

    • 0 avatar
      gslippy

      @psar: Yes, the torque this car needs already comes from the electric motor.  Diesel does suffer from shelf life issues, and that would be a problem with the Volt.

      The bigger issue for diesel is that it’s a niche product in the US that only enthusiasts yearn for.

    • 0 avatar
      John Horner

      Torque is irrelevant in the context of a generator set. Power is all that matters. For a given power output, diesel engines are heavier and more costly than are gasoline fueled engines. Emissions control is also devilishly hard and expensive for diesels.

  • avatar
    mcs

    How many KWHs will it take to charge the battery when the thermal management is active? I think we’ll see  more than 13 kwh to recharge in that case.

    According to the official Volt web site: A liquid thermal cooling and heating system keeps the battery at a comfortable temperature as it’s being charged and discharged
    That won’t come for free. It will take additional power to heat or cool battery depending on the temperature and increase to cost to recharge the pack.

    • 0 avatar
      Steven02

      Sounds like this will depend on the environment that it is being charged in… a garage.  It could be minimal though depending on insulation of the battery and how much energy it takes to heat/cool it.

  • avatar

    3,800 lbs seems ridiculous to me. Yeah, I know, when you have two separate power plants, either of which can run the car by itself… but it still seems ridiculous. My Accord weighs about 3,200. Of course, GM has not exactly shown proficiency at shaving weight off. The Miata weighs just north of 2400 lbs, and the Solstice and Sky–same size, same concept–are about 400 lbs beyond that.
    I hope these things do better than it sounds like they will. I mean, it would be great for an American company to hit a home run; it would be great to shave something off of our use of carbon-based fuels, not to mention products of nasty little dictatorships. But I’m not very sanguine. I also can’t help thinking that had Toyota tried this concept they would have done a much better job.

    • 0 avatar
      musiccitymafia

      Maybe they tried ….

    • 0 avatar
      Steven02

      It is pretty high.  GM’s vehicles right now are generally overweight.  GM started making better vehicles, but paid less attention to weight.  Once of the reasons the Cruze is over weight and by association, the Volt.  It will have to get lighter to be more efficient.  It could have turned out better had GM not used an already existing overweight platform.  But the 2 drive trains do make up a good deal of the extra weight.

  • avatar
    Trend-Shifter

    Perhaps it is just part of their longer term marketing and engineering strategy.

    1.  Get the best numbers at launch.

    2.  After all the hype has worn down have a program update to add the screen option “maximum battery life” mode. 

    Help/About Volt – version 1.2 :o)

  • avatar

    “I also can’t help thinking that had Toyota tried this concept they would have done a much better job.”

    David, I think you nailed it there.

    And Paul… love the choice of picture to accompany this article.

  • avatar
    gslippy

    The Volt’s highway fuel economy has little to do with its Cd, and much more to do with weight (friction).  A 0.28 Cd is excellent, and many cars with such a Cd can get better fuel economy.

    My 05 xB is a smooth brick with a Cd of 0.35, yet gets 35 mpg highway @ 3000 rpm from a 1.5L engine.  The key is its light weight at 2400 lbs.

    At the other end of the spectrum, while towing about 1800 lbs this summer with a fully-loaded  09 Sedona, I only got about 12 mpg instead of the rated 23 mpg.  The problem: a total road weight of over 7300 lbs.

    Moreover, weight is why the Volt runs out of steam on big mountains, as found by other reviewers.  This car would be much more economical if put on a diet, but the driving experience wouldn’t be as nice.

    • 0 avatar

      I know I’ve already said it, and you’ve said it well, but the weight just boggles my mind. What were they thinking? Or ignoring?

    • 0 avatar
      Ooshley

      Aerodynamic drag is THE single greatest contributor to power required, and thereby fuel consumption for a given engine, to travel at highway speeds.
      Weight affects acceleration, so is important in stop/start city driving.
      As I mentioned earlier, Cd means nothing in isolation, it is a co-efficient for the drag created by a shape. e.g. It’s the same number for a sphere the size of a tennis ball as it one as big as a house but it’s pretty obvious which is harder to push thru the air (even if they weighed the same).
      CdA however, takes in to account the frontal area of a vehicle, THIS is the only measure by which a genuine comparison can be made.

    • 0 avatar
      John Horner

      Weight is a almost a non-issue at highway steady state cruising. Aerodynamic drag dominates. Weight is, however, a huge issue for climbing mountains. I said long, long ago that the Volt was going to have a big problem climbing long grades. Once the battery is depleted you are left moving a 3800 lb vehicle plus its occupants and luggage with about the same amount of power as a late model vintage VW bus. Did you ever drive one of those things fully loaded up a mountain?
       
       

    • 0 avatar
      musiccitymafia

      Don’t forget the Energy of Deformable Bodies. A former chief engineer at Goodyear (it may have been Bridgestone, he was a roommate of my dads a long time ago in university) once told me … 60% of the energy a car uses is to deform the tires as it rolls down the road. I’m sure this number has changed over the years … but it’s what we’ll pay for “comfort” and a little thing called “control”. Have you ever tried to deform an inflated tire? Obviously the deformation required is a direct function of the weight and has little to do with aerodynamics (unless you can create a little airfoil under the car with speed and/or a spoiler).

      PS – I just jacked up the tires on my truck to 40 psi to monitor the difference (and I’m adjusting my driving since I was bouncing all over the road at the beginning).

    • 0 avatar
      Daanii2

      No, even rolling resistance (of which tire deformation is only a part) is nowhere near 60%. And rolling resistance increases less than linearly with speed. But aerodynamic drag increases at speed cubed.
       
      That’s why drag takes so much energy at highway speeds. At those speeds, rolling resistance is almost just rounding error.

    • 0 avatar
      SVX pearlie

      Fun fact from automotive engineering: in most “normal” cars, somewhere between 45 to 65 mph, the aerodynamic drag and rolling drag balance, depending on the specifics of the drivetrain and aero package.

      I have no reason to doubt this rule of thumb still holds true for the Volt, Prius, or Leaf.

  • avatar

    How long will it take for the Volt to pay for itself for the average consumer?  What does GM project the  average life of the Volt to be?

    • 0 avatar
      mcs

      The problem is that for this class of vehicle, there is no average consumer. Too many factors like the local cost of electricity, terrain, and climate effect the cost per mile. In some extreme cases, the Volt could cost you more than an ICE vehicle. If you have California tiered electric rates and steep terrain, it could take $4.00 in electric power to go only 25 to 30 miles. Conversely, if you have a .06 rate and flat terrain that will take you 40 miles on 72 cents, it’s a different story.

  • avatar
    Rod Panhard

    When I look at GM’s terms for the Volt lease, it seems obvious to me that they want customers to lease the car. From my perspective, they’re turning over part of their R&D to the customers. That leasing is popular in the part of the country where we have higher percentages of wealthy eco-weenies really works out to GM’s advantage.

  • avatar
    M 1

    Another Volt article.
     
    I just want to know, WTF is that in the picture accompanying the article?

  • avatar
    philadlj

    The VW Phaeton was engineered to be capable of being driven all day at 186 mph with an exterior temperature of 122°F whilst maintaining the interior temperature at 72°F. Those were concrete goals that were set – and met – by Volkswagen.

    Highly-publicized, stat-based promises shouldn’t be made casually. If the Volt team had set low, achievable goals and met or exceeded them, they’d be looking a lot better right now. Every promise they break hurts their credibility and loses one or two well-informed customers who were already on the fence.

    • 0 avatar
      SVX pearlie

      I doubt they’re actually losing any *real* customers. The anti-chorus made up their minds long before the Volt Concept was ever revealed, way back when GM chose not to produce the unviable EV-1 electric car.

      You can see this with the jumping on news when goals *are* met, or positive news is announced. The 230 mpge criticism is a good example of this. GM didn’t pick that number out of the air, they simply applied the methodology that the government laid out. That 230 mpge is a valid number, but the anti-chorus went apeshit over it.

      In comparison, when Nissan picks a non-current test for the Leaf, hardly a peep.

      Fair and balanced is done better by Fox News than a lot of blogs on Volt.

    • 0 avatar
      Steven02

      You sure those were met?  Can it drive for 24 hours on its gas tank at 186 mph and 122F?  Honestly, that is the type of criticism that people have for the Volt.

  • avatar
    GarbageMotorsCo.

    Is the Volt going to be backed with a 100 thousand mile warranty?

    Sure would add a little comfort for those *guinnae pigs living with a brand new design with zero reputation for reliability, quality nor longevity. From Government Motors of all companies.

    Yikes.

    *The ones that aren’t giving it back after the 36 month lease is up…..


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