At Witz' End: My night with range anxiety
I left the dinner meeting around 9:00, with home roughly 60 miles away...no challenge for an engine-powered vehicle, even relatively low on fuel. You can always find an open station.Not so on this 1997 night. I was driving an EV1 development vehicle freshly equipped with an experimental nickel-metal-hydride (NiMH) battery pack. We were developing NiMH - which was promising double the usable energy of our '97 advanced lead-acid (PbA) packs in about the same (nearly 1200-lb.) package - for the '99 model year.
As GM Advanced Technology Vehicles' test and development manager at the time, I routinely drove PbA EV1s home and back, re-charging overnight, during the summer. My 60-mile mid-Michigan commute was easily doable in warm, but not cold, temperatures.
When the mercury sank, so did range, due partly to reduced PbA performance but mostly to lost vehicle efficiency. Our 50-psi Michelin low-rolling-resistance tires became just average at low ambient temperatures. Cool seals, bearings and lubricants have more friction. The air flowing over and around our 0.19-Cd electric bullet got thicker and more viscous as temperatures fell. Then there are accessory loads: lights, heater and (in wet weather) wipers.
But this was a hot, dry summer night, my NiMH pack should have been good for 120 miles, and my after-work meeting was only 30 miles from work. Should have been a piece of cake to get home afterward, even with lights on at 70-80-mph freeway speeds. But it wasn't. (post continues after the jump)
I missed a turn at the first freeway split and wasted maybe eight miles driving to the next exit and back, but something else was not right. As the EV1's very accurate range gauge turned pessimistic, telling me I would not get home before running out of volts, I shut off the A/C and incrementally reduced speed. But I couldn't risk turning off the lights or going too slow on the freeway. I pondered how thrilled my wife would be come out to rescue me, and the risks of leaving the car on the shoulder overnight.
Shortly before my exit, the EV1 went into its limited-speed, "limp-home" low-range mode. I crept along the shoulder a couple more miles to my exit, then - ever more slowly - eight more to my garage. No fun, not safe, but it got me there. Whew!My one-hour drive had taken more than two, elevated my heart rate and caused serious sweat production. And what if I'd had to make a stop, or pick someone up, on the way?
The problem was traced to a NiMH trait (at least at that early stage of development) of which we had been unaware: it lost energy capacity when hot. Because of this, our engineers added battery cooling ducts around the pack for '99, and the NiMH option was not offered in hot-weather Phoenix and Tucson.
This was the first time I experienced serious range anxiety. We've all had the experience of running low on fuel in conventional vehicles with no station in sight. And we've either found fuel in time or had to get out and walk to bring a can back to the car.
Unfortunately, we can't carry a can of volts. If an EV goes dead, you leave it. If you're really lucky, you might get close enough to a home or business whose owner will let you plug in, but what will you do for the next few hours while it slowly charges on house current? The other option is to retrieve it later with a tow truck or flatbed. And forget the rest of your trip.
In my opinion, range anxiety is the single biggest obstacle in the way of widespread consumer acceptance of battery electric vehicles. Every EV at any price can carry only a finite amount of energy and will consume it at a (highly variable) rate dependent on its size, weight, feature content, load, operating efficiency, weather and, yes, operator skill.
Our original EV1 carried 16 kilowatt-hours (kWH) of energy – roughly half-a-gallon of gasoline – in a large, 1170-lb. T-shaped pack of 27 PbA batteries that ran down the wide center console and behind its two bucket seats. Given that an electric propulsion system is about three times as efficient as a typical internal combustion engine (ICE) powertrain, you could think of that gasoline equivalent as more like 1.5 gal.
How far will your car go on 1.5 gallons? To achieve a reliable real-world range of even 60-70 miles, our EV1 was designed and built from the tire patches up to be the most energy efficient practical vehicle that ever rolled down the road. Some skilled drivers could feather-foot 90, or even 100, miles out of one on flat surface streets on a warm day. Our optional '99-model NiMH pack could virtually double that.
We know that today's li-ion batteries should pack nearly twice the energy of NiMH and quadruple that of PbA. But they are still fairly large, bulky and heavy and will likely be much more expensive. EV makers, as always, will face the decision of how much to carry on board -- how much cost, weight and packaging will be needed to achieve how much on-board energy?
Battery EV owners will have to fully understand how to operate within their vehicles' real-world range, which will vary with conditions, each day, and exactly where and when they can recharge. As the infrastructure grows (with heavy taxpayer, utility and maybe automaker investment), recharging at work should be possible for some, and large shopping and dining areas should offer public charging. But they won't drive them cross-country any time soon.
One well-proven (but expensive) way to eliminate range anxiety is to marry an ICE to the electric motor through a complex control and transmission system. This is the essence of Toyota's and Ford's parallel hybrid systems. Another is to add a smaller, lighter ICE for range-extending battery charging only. This is GM's (also expensive) series-hybrid Voltec (neé E-Flex) system everyone hopes will be available in the 2011 Chevy Volt and, in time, other GM cars.
GM says the Volt's li-ion pack will carry 16 kWH, exactly the same as our original '97 EV1's PbA pack, but will be much smaller and about a third the weight. And, because the Volt will be a practical four-seater, necessarily heavier and less efficient than the EV1, that energy will propel it only about 40 miles on a charge. Then that very efficient little ICE will crank up to help complete the trip, no matter how far. What range anxiety?

Click above for high-res image gallery of the 2011 Chevy Volt
Award-winning automotive writer Gary Witzenburg has been writing about automobiles, auto people and the auto industry for 21 years. A former auto engineer, race driver and advanced technology vehicle development manager, his work has appeared in a wide variety of national magazines including The Robb Report, Playboy, Popular Mechanics, Car and Driver, Road & Track, Motor Trend, Autoweek and Automobile Quarterly and has authored eight automotive books. He is currently contributing regularly to Kelley Blue Book (www.kbb.com), AutoMedia.com, Ward's Auto World and Motor Trend's Truck Trend and is a North American Car and Truck of the Year juror.

Reader Comments (Page 1 of 3)
Roy Mercers 12:18PM (4/01/2009)
Stupid ant-american comment from NOZ in 3...2....1
Reply
ronEbear 12:39PM (4/01/2009)
Americans are such ants.
(stupid ant-american comment)
paulwesterberg 1:24PM (4/01/2009)
American cars are pants!
Noz 2:13PM (4/01/2009)
How about an anti-douche comment dedicated to you Roy. Enjoy.
BlackbirdHighway 12:45PM (4/01/2009)
Yeah, I get anxiety every time I fill up my gasoline car. Am I sending more of our precious currency to another country? Are those dollars going to end up sponsoring some terrorist bent on attacking the USA? Or am I just helping another rich oil sheik buy yet another incredibly huge yacht? Am I contributing to another Exxon Valdez disaster? Am I helping to ruin the planet's climate? Are we headed for another economy destroying oil shock? Is that peak oil just on the horizon?
Give me an EV with at least 200 miles range that I can power from my rooftop solar panels and I don't think my range anxiety will be so bad, and all those other ones go away.
Reply
jpm 1:40PM (4/01/2009)
Well said, thank you.
Noz 2:16PM (4/01/2009)
And American, or for that matter, Western (i.e. French, British, Dutch, etc) oil corporations who are involved on in the oil business aren't culpable in this?
It's only the others who want to do harm...not us of course. We simply want to sow the seeds of peace and prosperity. Get off your fking high horses.
Yeah it's great that you want to change your ways and go electric. But don't do a whole song and dance about righteous you are while everyone else is out to get you.
Chris M 9:33PM (4/01/2009)
Blackbirdhighway didn't make it only about one country or even one region, Exxon is a multinational based in the US, and everyone everywhere is involved in climate worries and peak oil.
Jeez, Noz, did you really have to go and prove Roy Mercers right?
You couldn't resist, could you. Just had to bite the hand that feeds you.
Noz 11:05PM (4/01/2009)
Prove him right? Are you warped or something?
Chris M 11:35PM (4/01/2009)
Well, he was expecting you to pop up with an anti-American comment, and you did.
QED
LloydChiro 9:44AM (4/02/2009)
I'm a little naive about this, but I think we already passed peak oil back in 2005, did we not?
Anyway, maybe I'm a sociopath, but I don't get anxiety when I fill up my tank. I am, however, making preparations to reduce my reliance on using a car to commute.
Noz 12:51PM (4/02/2009)
CHRIS M:
I'm doing what I think is right...I couldn't give a rat's ass what he thinks.
btenney 8:37AM (4/09/2009)
Your rooftop solar panels need to be about a half acre in area to reliably charge every day.
Snoopy 7:48PM (6/04/2009)
Blackbird makes a great point, no doubt.
One of the main reasons I'd like to move to an EV (when I get my own first car) is because I'll be able to produce my own energy via a solar panel I also plan to purchase. It might not be able to cover 100% of the charging, but we're on hydro anyway. 100% zero emissions folks!
steve ostling 1:31PM (4/01/2009)
Your car looks great... However, We are getting older.. now 69 years old
and need a car that is not so low to the ground.. more like the Honda CR-V
as It is about the right height off the ground... way easier to get into....
and better visability when you sit up higher.
You should have at least eight inches clearance off the ground.
I really don't believe that it will cause that much more drag.
Reply
LaughingMan 1:13PM (4/01/2009)
"And, because the Volt will be a practical four-seater, necessarily heavier and less efficient than the EV1, that energy will propel it only about 40 miles on a charge. Then that very efficient little ICE will crank up to help complete the trip, no matter how far. What range anxiety?"
My problem with this logic is that if driven correctly, the conventional engine, the gas tank, the emission control system in the Volt are dead weight. Just a few hundred pounds of steel, plastic, and gasoline that only serve to exist for the maximal case, and weight down the car to perform less efficiently in the average case.
People blast modern day full hybrids like the Prius for carrying around "dead weight" in the form of the traction batteries... they make the mistaken claim that the extra weight of the battery reduces highway mileage, assuming that the hybrid system does no good in a highway case...
But where are the people making the inverse argument about the "range extender" feature on cars like the Volt? If the hundreds of pounds dedicated to the engine, the gas tank and emissions control were swapped out for batteries, you'd have a 300+ mile range vehicle that performs better to boot. Guys at Tesla have *proved* that.
I understand range anxiety... but is sacrificing tremendous range because you need to huck around dead weight worth relieving that anxiety?
Reply
UH2L 4:12PM (4/01/2009)
Aren't extra batteries meant to extend range beyond what we typically drive in a day dead weight too?
It would be interesting to do a comparison of lb per mile of range for extra batteries versus the IC engine. I know the 1.4 L engine is probably bigger than the Volt needs, but for GM to develop and tool up for a completely new engine would make the business case for the Volt even worse. If the Volt sells, well, I would think that GM will put in a smaller engine. I also see people dismantling their Volts and doing it themselves, like by putting in a motorcycle engine.
Paul 10:25AM (4/07/2009)
Sure would be a sweeter package if the ICE+tank was a removable module that could be easily and safely popped out and left in the garage. Pop it in when you have a longer trip on your plate and save hauling the trash when you don't need it.
ug 1:23PM (4/01/2009)
The Volt, if it gets produced, will be like the Hitler-era VW Beetle because it will basically have to have been funded by the state. We've got much larger problems than reminiscing about EV1 range anxiety here, folks. GM is done and the rest of the auto industry is barely holding on for dear life.
Reply
ronEbear 1:27PM (4/01/2009)
The only difference - a big one at that - is that the Beetle was a car that people actually wanted and could afford.