Volt Car FTW

Moving transportation off of crude oil is vital; pick your reason: energy prices, national security, war, military spending, pollution, environmental devastation, CO2... Whether your political views run left or right, down the middle or indifferent, there are reasons to support moving off of gasoline. Tea Party members can support the reduction in this massively government subsidized energy source. Tree Huggers can support the cleaner air. The indifferent can enjoy the decline (or at least slower rise) in gasoline prices as demand is decreased and competition is increased.

Toward the goal of moving away from oil, the Chevrolet Volt is an important car for America for two primary reasons. First, it allows electricity to be the primary fuel without any of the concerns that many people have about pure electric vehicles. The Volt is a plug-in hybrid* that can be "fueled" by electricity or gasoline. If the car has been plugged in, then the Volt uses its battery power for the first 25 to 50 miles (usually about 35 miles) of travel. If you need to drive more and don't want to stop to plug in then the Volt has a gas tank and an on-board gasoline generator that can move you another 340 miles down the road. At that point it operates like any gas car in that you can fill up at any gasoline station and keep on driving. The next time you plug in the car, it goes back to using cheaper, cleaner electricity. It is the best of both worlds.

According to the U.S. Department of Transportation most Americans drive less than 30 miles each day. This means that with the Volt, most days will be completely gasoline free. Electricity will be used for commuting and all the in-town short trips, while gasoline will be there when you need it for a road trip to Vegas. If you are unsure of, or cannot use a full-electric car, then a plug-in hybrid with an electric range to cover "most days" is a great way to move the majority of your driving to electrical power and still have the safety net of all those quick-fill gas stations.

The second reason that the Volt is important, specifically to America, is that it is made by an American Company that has a loyal following. If a new technology like this had been introduced by a foreign car company, there are some people that would never consider it and even disparage it. The Volt has taken a couple of knocks from Rush Limbaugh, but Chevy diehards will ignore this completely. As their ads say "Chevy Runs Deep".

Americans know that General Motors is here to stay. As the recent US government bailout and resurrection IPO proved, GM is not going away. They will be here to honor their warranties and service their vehicles. Additionally, potential US customers know that the vehicles are being assembled in an American factory and that their payments are, at least in part, going in to the pockets of American workers.

The Volt reaches out to an audience that has never been interested in a car like the Prius. For example, when NASCAR's Rick Hendrick bought the first publicly available Volt in a charity auction, an entire segment of America was introduced to this car technology as something really cool. Yes, it is different technology than the Chevy that their Dad drove, but it comes from that same company and carries the same bow-tie logo that they trust.

The Volt will be the first opportunity for many people to experience an electric motor bigger than a golf cart. In a Volt you can feel the high-torque electric motor acceleration. The Volt will be the first chance for many to have the "EV Grin." In short, it is fun to drive. Plus it has a lower fuel bill and a quieter ride.

The Volt will also give people a choice of how they fuel their driving. They can plug in, filling up on locally generated electrons, putting money into their local economy. Or they can pump up, knowing that most of that money is going out of the country and some of it is going to regimes that don't like our freedoms or way of life. The point is the Volt gives them a choice.

Conclusions
The Volt is an eloquent machine that Americans can be proud of. When plugged in nightly, the Volt is fueled with enough locally generated electrons for most people's daily driving to be "energy independent." Because the Volt can be run on gasoline too, there is no need to be concerned about range limitations or charging times. Many people that would have ignored "yet-another-foreign-hybrid" will give a Chevy a chance.

References
Volt Specifications
Rick Hendrick Buys a Volt

Rick Hendrick fields 4 Sprint Cup teams:

• Five time consecutive Sprint Cup Champion in the Lowe's #48 Chevrolet Impala SS driven by Jimmie Johnson.
• Four Time Sprint Cup champion #24 Jeff Gordon
• #5 Chevrolet driven by Mark Martin
• and #88 driven by NASCAR’s most popular driver Dale Earnhardt Jr.

* Call it a range extended electric vehicle (REEV) if you'd like.

You Don't Know EVs

Mass market electric vehicles (EVs) are coming soon to a dealership near you*. The Nissan LEAF and Chevy Volt are both scheduled to begin delivery in early 2011. These vehicles are very different from the gasoline powered cars that most of us are used to driving. EVs are new to the mass market and people are asking questions. These questions, however, often come from their gasoline driving experience. For example, when I am showing my EV to the public the typical questions are:

• How far can it go on a charge?
• How long does it take to recharge from empty?
• How fast is it? (top speed & 0-60MPH)

These seem like important things to know about a car, and they are; however, most people are asking them without really understanding the question. I'll explain. If you are willing to take a step back, and look at personal transportation from a fresh perspective, EVs are a whole new opportunity.

"How far can it go on a charge?"
When people ask this, what they often really want to know is, "Will this go far enough for my needs?". Most people don't know how far they drive on a typical day. The numbers that most people know are: one, how many miles they get on a tank in their current vehicle and, two, how far it is for that long annual trip they take. Neither of these numbers apply to a commuter EV, yet the EV range value will be compared to them. When they hear that an EV can travel 100 miles or 120 miles, this is compared to the 300 plus miles that they get per tank or the 580 miles to grandma's they drive every other year. This makes the 100 mile EV range sound far too small and EVs are dismissed as unusable or "not yet ready". They don't realize that 80% of people drive less than 40 miles per day.

Less than 40 miles per day for most people means that a 100 mile range is more than 2.5 times the distance that most people need on most days. And unlike a gas car, EVs can be conveniently charged overnight in your own garage and start out each day fully topped up.

Viewed another way, how often are you filling up that gas tank? If a tank carries you 350 miles, and you are filling it up once per week, that is an average of 50 miles per day; well within the capabilities of modern EVs.

If you want to quickly map your driving, try the Nissan 100 mile drive test. Plug in your own locations for a busy day. Try home to work, to the gym, errands, dinner, and back home. Or try home, school, shopping, pick up kids, soccer, dance, then back home. Can you do these with miles to spare? For most people the answer is 'Yes'. This means an EV can fit most people's lifestyle well. If your answer was 'No', read on, option #5 below might work for you.

What to do about that annual long trip? There are several options.

1. Keep a gas 2nd car around. Use your EV whenever you can and the gas car when the EV won't work. See Hybrid Driving without a hybrid car. If you drive the gasser less than 5k miles per year, you may be able to put it on recreational insurance rates.
   
2. Borrow a gasser. Swap cars with a friend for a week. They get to try out an EV and you can take your trip.
   
3. Rent a car. The annual savings you get from not buying gas will allow you to rent a nice vehicle for an extended period of time and still come out ahead.
4. Ride Share. Programs such as Zip Car have been expanding. If there is one in your area, this can complement EV ownership well. Just log-on, find a car parked near you, reserve it with a click and it is yours when you need it.
5. Buy a PHEV: Rather than buying a pure EV, buy a plug-in hybrid like the Chevy Volt, the 2012 Prius PHEV, or the Fisker Karma. You don't get all the benefits of a pure EV, but you can utilize a gas station when needed.

The new perspective on range is how far per day, not how far between fill ups. On to the next question.

How long does it take to recharge from empty?
No one wants to be stuck for hours waiting for their car to charge before they can go someplace. Vehicles represent our freedom. When you drive an EV, you can be less restricted, not more.

Going to the gas station is inconvenient, so we tend to put it off until it cannot be avoided. Therefore a gas car is usually being filled up from empty. Don't assume the same with an EV, in fact, the opposite is usually true. For an EV, the charging station is right there, in your garage, the one that you are already driving to when you go home. It is not a side trip that you have to make to fill up. This means that you can plug in each day, even if you only drove a few miles.

Until you stop going to gas stations, you may not realize what an inconvenience they really are. Compare this to your cell phone. You plug in your phone overnight and it is fully charged, ready for all your needs the next day. That is convenient. By contrast, what if you were not allowed to plug in your phone? Instead, you had to take it to a "phone station" each week for a "fill up". This would be intolerable, yet it is OK for our cars because most people don't know of any other way.

Continuing with the cell phone analogy, do you know how long it takes your cell phone to charge up? Probably not, it depends on how much you have used it that day, and most likely you don't really care because an overnight charge is more than enough. The only time you pay attention is the few seconds it takes to drop the phone into the cradle and then to grab it the next morning.

It is the same with an EV, your attended time is just the few seconds to plug it in each evening and unplug it each morning. The charge duration is completed while you sleep. Most days the battery pack is more than half full at the end of the day, so charging to full has a head start. Public charging infrastructure is nice to have, but it is not required for EVs to be usable.

The new perspective for charge time is not how long does it take, but how much of my time does it take. EVs take far less of your time.

What if I am stranded with a drained battery, how long will that take?
Modern EVs such as the LEAF will show you on the nav system how far you can go. If your destination is not within the circle, you cannot get there without stopping to charge. When you do stop to charge, no one said that you must charge up all the way. If you are plugged into a standard 120V outlet this will give you about 7 miles of addition range per hour. A Level 2 outlet that you'll find at EV charging stations will give about 16 miles of additional range each hour you are plugged in. So a stop for lunch or dinner can give you the extra miles you need to get home or your stop for the night.

Tom Saxton is a Seattle area Tesla Roadster owner. He has blogged about driving his roadster down Highway 101. He stayed at the coast, charged overnight, drove into Portland to meet up with NEDRA, raced his Roadster, charged between races, and then headed back home. He was able to make the entire trip without ever waiting for the car to charge. Charging was always something that he could do in the background while he was sleeping or waiting for his next turn on the line. Granted the Roadster is out of most people's price range, but you can do the same thing in a LEAF on a smaller scale.

The new perspective on charge time is the charging rate in miles per hour, not hours till full.

How fast is it? (top speed & 0-60MPH)
I think most people that ask this question are wondering "Is this a golf cart or a real car?". There have been many low speed EVs and glorified golf carts that have been pitched as the solution to transportation. Skepticism here is well deserved. Low speed EVs have niches that they can serve very well such as retirement communities or commutes that can be done exclusively on residential roadways. However, when they are sold outside of these niches they fail to meet the needs and give all EVs a bad name.

Perhaps in part because of the "golf cart" experience, many people assume there are things that an electric motor is just not suited to do. In fact, other than burn gas directly, electric motors can do everything and more that internal combustion engines are used for today. Such as, the little white car shown in the picture to the right. It is an electric car that can run the quarter mile in 10.4 seconds. That is supercar territory. And it was done as a DIY project with a Datsun and two forklift motors.

What about big loads? Surely electric motors cannot handle hauling. Think again. Diesel-electric trains have moved big loads for years. The diesel is only used to generate electricity. It is the electric motors that do all the work of moving the load. The same is true for many types of giant hauler trucks like the one shown to the right. Large mining machines, NASA's huge Crawler-Transporters, some submarines and ships also use electric motors.

Assuming all electric motors are weak based on riding in a golf cart is like seeing a moped and assuming that a Dodge Viper is not possible.

Performance, hauling, & range are all possible if you are willing to pay for them. In the '90s, Ford and Chevy both made electric trucks. Ford, NaviStar and others have new generations of EV trucks planned.

The new perspective: EVs can be whatever we design them to be.


Conclusions
To truly understand if an EV would work for you, it should be compared to your needs, rather than to the gasoline car that you drive today. This means that you have to understand your current driving habits. How far do you drive in a day? Try resetting your trip meter each morning this week to see. How many hours does your car sit parked each day? If an EV was plugged in for just those hours, would it get enough range for your current driving needs?

EVs are a new tool for your transportation needs. They do not work in all cases, but they can work for many people and coupled with a 2nd car or a range extender, a large percentage of your driving can move off of gasoline.

Prius, Insight, or Volt?

The concept Volt looked cool. It had hard lines, it had an edge. The production Volt, however, looks much more like a Prius to me. Regardless of how cool these hard lines looked, they were not aerodynamic. Sure they had improve this, but does that mean that all cars must look the same.

The original Insight, although not too pretty, had a unique look. That once unique look is gone in the new "back from the ashes" version of the Insight. The new Insight looks like a Prius.

5000 csblog points (whatever those are) if you can correctly identify each car below.

Comparing them side by side, like this, the Volt still stands out. It is just not as cool looking at the concept cars was (few production models are). There are more important things about a car than how its looks, but car purchasing is a bit of an emotional experience, even for a numbers-engineering guy like me.

What is the Volt's MPG?

In August '09 GM launched the "230" marketing campaign. They claimed that the Chevy Volt will get 230 MPG. Soon after GM launched the campaign, the EPA said that it could not support these claims, and Nissan pointed out that using the same calculation scheme the all-electric LEAF would rate at 367 MPG.

Plug-in hybrid cars are scheduled to be on the market in 2011. They promise to have significantly better gas mileage than traditional hybrids. These will be partially 'fueled' from the electrical grid with the balance of propulsion coming from gasoline (or ethanol). If a car uses electricity and gasoline, how do you rate its MPG when not all of the Ms are using Gs? How can an all-electric car even have an MPG?

PHEV, EREV, REEV; what are they?

The above questions are further complicated by the fact that PHEVs come in two different types. There are parallel-series plug-in hybrids such as the plug-in Prius and BYD cars and there are series plug-in hybrids such as the Chevy Volt or the Chrysler Envi line. Plug-in series hybrids are referred to as extended range electric vehicles (EREV) by GM and range extended electric vehicles (REEV) by Chrysler.

A series plug-in is propelled exclusively by an electric motor. The electricity comes from batteries for an initial range and then after the batteries are exhausted, the electricity comes from an on-board generator.

• AER-All Electric Range
• CSM-Charge Sustaining Mode (i.e. the flex fuel generator provides most of the electricity required to propel the car.)

For a parallel plug-in, it is not as clear when the gasoline engine will run. It will run when the batteries are low just like a series plug-in but it can also run when the vehicle is at high speed, during acceleration, or when climbing hills.

Given that multiple fuels will be used, how can you measure fuel efficiency? Some methods include: energy equivalence, pollution, and cost. Since the focus is currently on the MPG ratings, we'll use energy equivalence.

disclaimer

For the rest of this article, let's examine the 2011 Chevy Volt as presented in the sticker above from gm-volt.com. It is unofficial but matches all the data that is known at this point. I must point out, that despite the big 230 MPG marketing campaign, real answers about the Volt's performance are still being held close to the vest, so many of the assumptions below may turn out to be incorrect. I'll leave comments below if/when I am made aware of any discrepancies.

assumptions

The first thing to note is that GM claims a 40 mile electric range for the Volt. However, to ensure the battery life they are only going to use ~10kWh of the 16kWh pack for the electric mode. This means that you can only get the promised 40 miles in city driving (or congested freeway driving). Aerodynamic drag and rolling resistance reduce the efficiency at higher speeds. For this exercise we'll assume that all 40 miles can be traversed with just 10kWh using the better city performance values. Note that if your first 40 miles of daily driving includes some high-speed driving, you might not get the full 40 miles before the generator kicks in.

Since we are already dealing with the complexity of two fuels, let's assume a 50/50 split of city and highway driving for the charge sustaining portion of the drive. Averaging the 50 city and 45 highway yields 47.5 miles per gallon after the battery is depleted. Given that the car changes operating modes at the 40 mile mark, we'll need to examine different distances. I'll use 25, 50, 100, & 200 miles assuming each starts out fully charged.

While these single trip numbers are helpful illustrations, a month of driving with commuting and an occasional longer trip is more interesting. For this example month, Mon-Friday driving will be 30 miles (all-electric). On most weekends, we'll use 25 miles per day unless we go for a longer drive to the beach or the mountains. For these long weekend journeys, we'll use 200 miles round trip and assume that you can charge at your destination.

Example Month:

23 weekday commutes = 690 miles electric

6 short weekend trip = 150 miles electric

1 long trip weekend = 200 miles = 80 miles electric + 120 miles gas

Example Total = 1040 miles = 920 miles electric + 120 miles gasoline

Miles	Electricity (kWh)	Gasoline Used (gallons)
25	6.25	zero
50	10	0.2
100	10	1.3
200	10	3.3
1040*	230	2.5

* one example month

energy equivalence

This method of comparison converts all fuel sources, be it watts-hours or gasoline, to an energy unit such as Joules. One gallon of gasoline is 132 mega-Joules. A kilowatt-hour of electricity is 3.6 mega-Joules. With this you can convert the battery energy and gasoline used on a given drive to get a Joules per mile rating. Most people don't have an intuitive feel for Joules per mile, so this would generally be converted back into MPG and noted as MPGe, regardless of the energy source or how silly that result sounds. While this does give you an interesting efficiency number, it hides the sources of the energy. It is an over simplification that often adds confusion especially when the 'e' is missing. The energy source is an important factor in both the cost and pollution of those miles. And in cases where majority (or all) of the 'fuel' is electricity, stating a MPG rating is just not right, as Nissan illustrated when they stated the all-electric LEAF would rate at 367 MPG.

These are not exchangeable items; it is like reporting how many miles per banana it gets. But MPG is a unit that the public is used to hearing and anything over 100 MPG is attention getting. That is impossible for the marketing types to resist. Don't be fooled by this, demand to know the consumption numbers in both modes and do your own math for your driving patterns.

Here is our table of examples expanded to add energy consumption:

Miles	Electricity (kWh)	Gasoline (gallons)	Total Joules (MJ)	Miles per Megajoule	MPGe **
25	6.25	zero	23	1.1	147
50	10	0.2	62	0.8	106
100	10	1.3	208	0.5	64
200	10	3.3	472	0.4	56
1040	230	2.5	1158	0.9	119

** use MPGe with caution, and please don't drop the 'e'

You can see in the table above that there is no MPG equivalent that is close to the 230MPG that GM is reporting for the Chevy Volt, not even the all electric 25 mile trip. While I could not find the exact calculations that GM used, I think I found the cause of the discrepancy. The DoE formula includes a multiplier, called the Gasoline-Equivalent Energy Content of Electricity Factor (Eg), to compensate for upstream efficiencies in the fuel source. Currently, the government is promoting the idea of getting off of foreign oil (sounds good to me), so this compensation factor is very favorable for electrically powered transportation (you can read the full EPA explanation here).

The value being used for Eg is 2.42 in 2000 and it might be higher in the 2008 version of this specification currently in use. This means that the electrically powered mileage is getting extra credit at a significant rate.

Applying this factor and you can see in the table below that the 230 MPG number that GM is reporting is achievable for a trip just around 50 miles.

Miles	GM MPG
25	355
50	226
100	100
200	72
1040	267

This is much closer to what the 230 campaign is claiming (as incorrect as that might be). And you can see how the Nissan Leaf scored over 360 MPGe. My understanding is that the EPA test track is a 10 mile loop with various speed, acceleration, stop & start zones. For a plug-in car like the Volt, they will drive it until the batteries are depleted and then do one more lap around the track with the generator running. This corroborates that the 50 mile calculation is the one closest to the magic 230.

The 106 MPGe for the 50 mile trip in the second table or the one month of driving example at 119 MPGe would still be a very impressive number to launch a marketing campaign around and it would not have the backlash that quickly branded the 230 MPG campaign as unrealistic hype. You can see the reception that Conan O'Brien gave it on The Tonight Show in the video below.

If you are a regular reader of this blog, you know that I support plug-in vehicles. And I have discussed the importance of "well-to-wheel" consideration. Well-to-wheel is looking at the full life-cycle of the fuel that you use. However, hiding this in a single MPG number is not the right thing to do. This is really more of a pollution value than a vehicle fuel efficiency value. Presenting it simply as MPG, sets up unrealistic expectations. I like the idea of a pollution indication per mile, especially if were applied to all vehicles. On a regular gas powered car with a 32 MPG rating, when you look at all the energy used to process, refine, and move the fuel, you might see that it has a pollution rating of 120 pounds of CO2 per 100 miles. Whereas a grid powered 110 MPGe PHEV might have only 15 pounds of CO2. That would stop the "long tailpipe" argument quickly. And as crude moves from easy to extract light sweet crude to the to deeper and heavier forms, the gasoline numbers will get worse, whereas as the electricity grid will improve as new wind turbines, geothermal and solar thermal plants come online.

The consumer could decide how important each the fuel economy value and pollution factor value is to them and shop according to their own values. They might decide that only one of the numbers matters and simply ignore the other or they may try to find a balance.

Despite the fact that GM has greatly oversimplified things and shown the best possible MPG that they could (without using all electric), they just might be able to get away with this. Looking at the example month, there is 1040 miles of driving, using just 2.5 gallons of gas. If one were to ignore all the watt-hours used, 1000 miles on 2.5 gallons is 400 miles per gallon of gasoline used. Miles per gallon of "gasoline used" is not the same as MPG, but if this is the number that people are seeing, they may just feel like they are getting more that the 230MPG promised. And if your concern is the reduction of oil use (and not vehicle efficiency), this is a valid number to consider.

conclusions

With plug-in cars, the game has changed. People are used to a single MPG number and change can be difficult for some. The marketing departments are going to want to fly these great MPG(e) numbers on a high flagpole, even if they don't apply to the real world because people will ask and they are great numbers. GM and other companies making plug-in vehicles should strive for integrity and rise above the temptation to hustle these as facts.

Consumers are going to have to consider more than just a single MPG number. There is a learning curve. Auto companies can help by creating tools such as a webpage where prospective buyers could input their driving patterns and information such as can they plug-in at work, etc. Then this webpage could generate a custom report with cost, consumption, pollution and other relevant information. Hymotion has a web tool to do just this for people that are considering a PHEV conversion. I hope GM creates one for the Volt too.

Now you are more aware and can be an informed skeptic when confronted with only an MPG number for a plug-in vehicle. Decide for yourself what aspects are important and do the math.

Links:

So Much For That; EPA Will Not Back Up GM's 230 MPG Claim

230 MPG? Stop the Madness! How the EPA Should Rate

Auto X Prize Throws Water on GM's 230 MPG Claim

Ignore the 230 MPG Claims by GMGreen Car Congress

Volt Specs

Argonne Study

Boston.com

Is The Chevy Volt Headed For The Trough of Disillusionment?

GM is planning to release the Chevy Volt in November 2010. Put simply, the Volt is a battery electric car with a built in generator. It can drive up to 40 miles per charge on just the batteries and then the generator kicks in. Like a conventional gas car, you can drive until the tank is empty and you can refill at any gas station and keep going as far as you like. Unlike a conventional car though, you can also plug it in, charge it up and then start driving from battery power again.

Did you catch the subtle wording above? The Volt can travel "up to" 40 miles. There is no guarantee that you get 40 miles out of that full charge. However, the "your mileage may vary" disclaimer is blatantly missing from press releases and other media. In fact, if you comb the mass o' videos and articles about the Volt, even the "up to" bit is often not present or only stated the first time. How far can you actually expect to really drive in electric mode? Who knows, that is not what GM is talking about.

GM recently kicked off the "230" marketing campaign. They claimed the vehicle would rate at 230 miles per gallon. That would be great, but it takes some creative accounting to get there. In electric mode, the EPA rated the Volt at 4 miles per kilowatt-hour. Using this number with the Automotive X Prize conversion to miles per gallon equivalent energy (MPGe) and the vehicle rates at just under 150 MPGe in all electric mode. Note that no actual gasoline is being used; this is just a measure of the energy spent. Then when the Volt turns on the generator, it does use gasoline with each mile. This is called Charge Sustaining Mode (CSM). When GM announced the Volt in 2007, they estimated that it would rate approximately 50 MPG in city CSM operation. GM has not updated this number for the actual production vehicle, so we'll use this estimate.

Using these two values, you can see that with short trips in the electric mode you can about 150 MPGe and as you continue past the battery range, the generator kicks in and the efficiency drops to 50 MPG. This means that all trips will fall between 50 to 150 MPGe. A 50 mile trip would be about 105 MPGe and a 200 mile trip would be about 55 MPGe.

Undaunted by this reality, the 230 flag was waved high. GM had a media event, did press releases, appeared on CNN Money and other TV shows to promote 230. But is this hype the right thing for them to do? I want the Volt to be a highly successful vehicle. It greatly reduces oil use and the associated pollution. This is good for national security and the air we breathe, but is building up the hype around the Volt only guaranteeing that it will be a disappointment?

Below is a graph of the Gartner Hype Cycle. This curve applies to many new technologies and the Extended Range Electric Vehicle certainly qualifies as new tech. The graph shows how a product can become highly anticipated and then not deliver on the wild expectations.

Note that these wild expectations don't even need to be from the company in question. The expectation could be set by the media or word-of-mouth. GM is saying 40 miles all electric and 230 MPG, there is a large portion of the population that are going to take this at face-value and expect it when this car hits the streets.

In hope of setting realistic expectations, here is a reality check, my attempt to cut through the hype.

1) The electric range will be less than 40 miles most of the time. And definitely less than 40 miles if:

• you have a lead foot - fast acceleration eats watt-hours
• your 40 miles includes highway driving - in other EVs, freeway-speed driving decreases the range by about 20%
• there will be some degradation as the batteries age - 80% capacity after 10 years would not surprise me

2) The gasoline mode (CSM) the fuel efficiency will be about 50 MPG. The official CSM MPG has not yet been published, you can expect highway to be lower than city. If you plan to drive the car 200 miles between overnight charges, you will only get about 55 MPGe. That is not bad (unless you expected 230 MPG).

Remember there are lies, damned lies, and statistics. The 230 number might have appeared in one obscure corner of an engineer's spreadsheet, but that does not mean it is what you will really get in daily driving. Much of the media and blogosphere called shenanigans on GM's 230 MPG claims. GM might think this was unfriendly media, but perhaps it has been the best thing that could happen.

More than ever, how you drive will greatly impact your consumption. You can get from 50 to 150 MPGe, still sounds like a marketable (hype reduced) car to me. Throw in foreign oil reduction and you have a car that can appeal to both flag wavers and tree huggers.

Related

"Patriotic Environmentalist", not an Oxymoron

Chevy Volt to be Sold on eBay

GM will do direct to consumer sales of the Chevy Volt using the online auction giant eBay. The online auction format would allow GM to sell the Volt at a premium without huge dealer markups. This would help GM to recoup the massive investment they have poured into Volt development.

Power is provided by a 16-kWh lithium-ion battery, which enables the Volt to travel up to 40 miles before the gasoline generator kicks in to recharge it.

The Volt should start selling online weeks before it is on the dealers lots with auction winners receiving their vehicles at about the same as the dealers get their first shipments.

Inner Workings of the Chevy Volt

Below is an animation from GM, presented by CarDataVideo, that shows how the Chevy Volt works. Plug-in series hybrids or Extended Range Electric Vehicles (EREV) have not been used for non-industrial retail vehicles so the concept is new to many of us. This is a good intro.

I was recently trying to explain to someone how the generator does not completely recharge the car, rather it keeps the batteries in a buffer zone around 25-30% charged. This animation shows that quite clearly.

So why do they keep the batteries in a buffer zone? Why not deplete the batteries completely and then run from the generator? A couple reasons. One to avoid fully cycling the batteries. Fully depleting the pack (or fully charging it) will reduce the lifespan of the pack. If you want the batteries to last for 100k miles, then need to avoid the 0-15% and 85-100% SOC range. So when you plug-in a Volt and it reports "full" it will really be at ~85% SOC. As long as it can deliver the promised range, this is the right thing to do for the life of the battery pack.

The second reason is that you may need more power than the generator alone can provide. The Volt has a 54kW generator and a 111kW motor. At first glance it mat seem like the generator is only about half the size it should be. However, it is rare that the engine will be at full capacity. Consider normal driving, how often do you have it red-lined? Even for aggressive drivers it is a very small percentage of the time. In the times that you do need the full power of the motor, such as passing on a hill, it is available to you because the batteries still have plenty of juice when the generator kicks in. Then as you go down the other side of the hill, gravity provides the acceleration and all of the generator's power can go to the batteries. And maybe more if you do some regenerative breaking. This means that the generator only has to provide more than the average amount of power used (even by an aggressive driver) in order to maintain the charge level in the buffer zone.

Another question, the video shows the generator turn off when the batteries hit the top of the buffer zone; why not have the generator charge the batteries all the way up to 85%? It could, but that would be using gasoline unnecessarily. There would be no advantage to the car's performance. The idea of a plug-in vehicle is to get as much of your mileage as possible from the plug-in power. By keeping the charge low, you get to fill it up with grid (or solar) provided electrons when you get home or to any charging station. This makes it cheaper to operate and reduces your number of trips to the pump.

Links:

ABG Volt Revealed

GM-Volt.com

Car Data.com