EV Range High Anxiety: Normal Driving May Cut Range In Half

Paul Niedermeyer
by Paul Niedermeyer
ev range high anxiety normal driving may cut range in half

Would you set out for a drive with your low fuel light on, knowing there was no place to buy gas? That’s the painful reality many EV drivers are going to be faced with every morning after unplugging their fully-charged battery and heading out on the road. Most conventional cars have about 50 to 60 miles left after the gauge hits empty, plenty of time to find a gas station. But according to a Consumer Reports test of a Mitsubishi i-MIEV, the stated range of 100 miles with a full battery is more like 60 or 50 under typical conditions, if you consider using lights at night, indulging in heat or A/C, or driving at 65 mph typical. I do. And so will most drivers. Disappointment with their $40k electric mini-car is inevitable. Just don’t say Darryl Siry or I didn’t warn you:

I wrote about the potentially misleading and confusing issue of EV range here, and former Tesla exec Darryl Siry has gone public with his concerns of EV makers’ unrealistic claims here, and more specifically, he took Nissan’s 100 mile claim for the Leaf to task here. The problem is well understood by EVers, but not at all so well by the public. Here’s the sixty second capsule version explanation:

IC engines operate at very low efficiency levels, from effectively zero% at a stop light, to maybe in the teens or low twenties at high speeds. We’re used to getting better mileage (range) on the freeway than in the city. But the amount of actual energy required to propel the car is much higher at speed; this is masked by the improved efficiency of the gas engine at those higher speeds.

An electric motor operates at close to 90% efficiency pretty much all the time, so there is essentially a direct correlation to the energy required to move the car, and the mileage (range). And since EV’s use no energy at a standstill (if the heat, lights and radio are off, as in the tests), city driving patterns are dramatically more favorable to EVs.

That explains why EV makers like Nissan and Mitsubishi are using the EPA City”, or “UDDS” driving cycle. This test cycle assumes an average driving speed of 19.59 mph and in the 22 minute driving cycle, it assumes you only break 40 mph once, for about 100 seconds, and never exceed about 58 mph. Not exactly a typical commute from the ‘burbs.

If the EV manufacturers used the US06 driving cycle, which more closely resembles typical US driving patterns, the projected range would be significantly less. But that wouldn’t look good in all the PR and ads. We’ve said it before and we’ll say it again: EVs potentially make great city cars. But head out on the highway, and you’ll be looking for an adventure all too soon.

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  • Guyincognito Guyincognito on Dec 18, 2009

    I'm a firm believer (despite my often skepticism) that EV's are the cars of the future. However, they are nowhere near ready (or needed) now. I always hear the average commute is 40 miles stat bandied about, and I'll accept that as fact. However, I would venture to guess that most people need to get groceries and pick up the kids from school a couple of times a week, nevermind regularly taking the kids to sports practice or going out to dinner, etc. A 70 mile range would not be feasible for such people. Will they exist as a niche vehicle for those rich enough to afford an impractical but likely not very fun second car? Sure. But we'll need another breakthrough before they are adopted on a wide scale.

    • Daanii2 Daanii2 on Dec 18, 2009

      I agree that electric vehicles are the way of the future. But also that they will have to be different from what we have now, or what the current carmakers will put out in the next five years. I think a serial hybrid electric car can be made that gets 0 to 100 miles per hour in 10 seconds, that burns diesel to generate electricity and gets 100 miles to the gallon. That kind of car will work much better as a drop-in replacement for our current gasoline cars.

  • Seabrjim Seabrjim on Dec 18, 2009

    Well put, Robert.

  • NotMyCircusNotMyMonkeys for that money, it had better be built by people listening to ABBA
  • Abrar Very easy and understanding explanation about brake paint
  • MaintenanceCosts We need cheaper batteries. This is a difficult proposition at $50k base/$60k as tested but would be pretty compelling at $40k base/$50k as tested.
  • Scott ?Wonder what Toyota will be using when they enter the market?
  • Fred The bigger issue is what happens to the other systems as demand dwindles? Will thet convert or will they just just shut down?