Three EV Lessons for Nissan from Tesla Motors

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In the all-electric Tesla Roadster, Tesla Motors has done an amazing job of designing and producing a car that shows the world how to build a great electric vehicle that is reliable and fun to drive, creating a driving experience that is far superior to that of a comparable gas-burning high end sports car.

Despite having Tesla's example, I'm concerned that Nissan is going to do a poor job with the Leaf. They've already made three missteps which I think need to be corrected before they start selling electric cars.

Overstating the Leaf's Range

Nissan has been saying the Leaf will have a 100-mile range, but they are basing this claim on the LA4 city driving cycle, not on a highway or combined cycle. Tesla says the Roadster's range is 244 miles, and that's a real number. If I drive 55 mph on level freeway, I get energy use consistent with that 244-mile range. From what Nissan has said, I suspect that going 55 mph on level freeway with no heat or A/C will yield somewhere around 80 miles. That's still an awesome range that will meet the needs of many drivers, but it's a disappointment that they entered the game by overstating their range with a number that requires driving even more conservatively than a steady 55 mph.

The vast majority of people who've had the opportunity to drive electric on a daily basis prefer it to driving gas. The only people I've heard of complaining about the electric driving experience are people who purchased an EV with inadequate range for their driving needs. The EV consumer has to take some responsibility to understand their real driving needs and the capability of the EV they are considering purchasing, but any automaker that does anything less than conveying a conservative and realistic picture of the car's capabilities is going to end up with a lot of unhappy customers and a public relations disaster.

Nissan: Get real range numbers out there now. Tesla Motor's detailed page on range information could be better by being far more visible on their site. Make sure the one or two numbers that are most visible to the public are representative of what consumers can realistically expect to get under conditions that are clearly stated. Beyond a simple number or two, also put lots of technical detail out there to satisfy the people who want all of the information and will be the early adopters that clear the path for the mainstream buyers.

Update: I arrived at the 80 mile figure by adding a generous 10% to the 70-mile range for 55 mph with A/C on as reported by Forbes. A MotorTrend article pointed out by mwalsh and evnow on the MyNissanLeaf forum after I published this post quotes Nissan Leaf chief engineer Hidetoshi Kadota as saying normal freeway driving at 60-70 mph without climate control yields a range of 105 miles. So maybe the Leaf's range is better than suggested by the negative Forbes article, but it's still the case that Nissan is not making any of this information available on their web site.

Not Fully Exploiting the Advantages of Driving Electric

Nissan is apparently making the Leaf drive like a gas car rather than fully exploiting the advantages of driving electric. Specifically, they are putting little or no regenerative braking on the accelerator pedal. Tesla does a beautiful job on this. As you press down on the accelerator pedal, the car accelerates more, just as you'd expect. As you let up on the pedal, you get to the point where the car is just coasting before the pedal is completely released. As you release more, the car starts using the motor as a generator to charge the battery, the more you release the stronger the effect. When the pedal is fully released, the regenerative braking becomes quite strong and will slow the car down almost to a stop. (This effect is stronger at slow speeds where you're likely to want to slow more quickly, and lighter at freeway speeds where you want a more gradual slowing to match traffic.) To slow the car more quickly or bring the car to a complete stop, you press the brake pedal to engage the car's friction brakes, just like driving on gas.

After getting used to driving a 2002 Toyota RAV4-EV, which puts only a little regenerative braking on the accelerator with more on the brake pedal, I was dubious of the Tesla scheme. (The Honda Insight and Toyota Prius are similar to the RAV4-EV in this regard.) After driving the Roadster for a few days, I found the Tesla scheme to be much better than the RAV4-EV. It has two big advantages over more closely emulating a gas-burner. For the sake of driving efficiency, I want to slow the car with regenerative braking as much as possible, every time you touch the friction brakes you are wasting energy by converting momentum into heat and brake wear. With the Tesla scheme, I know exactly when I switch from efficient regenerative braking to wasteful friction braking: when my foot moves from the accelerator to the brake pedal. Aside from helping me drive more efficiently, and reducing wear on the brake pads, the Tesla scheme is simply a better way to drive. I can control speeding up, maintaining speed and slowing down all with one pedal. With just a little bit of time behind the wheel, it quickly becomes a more natural and comfortable way to drive. This is especially nice when driving downhill, it's just so easy to control your speed, driving a gas car seems primitive. The only complaint I've ever heard from a Tesla owner about how this works is that they want more regenerative braking on the accelerator, enough to fully stop the car at a light. Personally, I think what Tesla has done is perfect: the mostly one-pedal driving is familiar enough that a first time driver won't have any problem driving the car, with a bit of practice it's a better experience, and the occasional use of the brake pedal keeps my brain-foot connection trained to use both pedals, reinforcing the old skills that puts your foot on the brake pedal instantly when required to slow or stop quickly.

Nissan: talk to some Roadster owners about the pedals. Drive a Roadster for a week or a month. It's important to get this right, it will give your owners a great driving experience sell a lot of cars.

Yielding to Unreasonable Demands for Artificial Traffic Noise

Nissan has yielded to the hysterical calls to add noise to electric vehicles. So far, Tesla Motors has resisted doing the same. All modern cars are quiet when driving slowly; the difference between a pure-electric car and a modern sedan is only audible in very quiet conditions. If quiet cars are a safety issue, then we should be looking at requiring all cars to make a minimum amount of noise at low speeds rather than singling out electrics and hybrids. There is no credible research to suggest that quiet cars are any more dangerous than other cars. Cars are only quiet at low speeds, when both drivers and pedestrians have enough time to react and avoid any problems.

Even if we make electric vehicles noisy at low speeds, they will still be inaudible in noisy environments. If anything, noisy cars that drown out the normal sounds of tires, fans, and pumps are more of a danger than quiet cars. So, if we're really worried about sound-related risks between automobiles and pedestrians, we should have strict laws for all cars that require minimum sound levels at low speeds, and prohibit sounds loud enough to drown out those minimum sound levels. But actually, that wouldn't help either. Just imagine what a parking garage would be like if all cars had to make a constant continuous sound, it would be like having a stadium full of vuvuzelas creating a cacophony that makes it impossible to discern any individual sound while training everyone to ignore the annoying buzz.

Instead of squandering an opportunity to have quieter cars, we should be taking real steps to improve safety for all pedestrians, bicyclists, and everyone else on the road. We should be studying the whole situation to find out if quiet is a real problem for pedestrians, considering all cars -- not just electric and hybrid -- and also the impact of natural or artificial traffic noise on quality of life. Does adding noise to all cars benefit anyone, or does it just crank up the level of background noise and make it harder to hear what's going on nearby? Does adding a constant warning noise to a car just train drivers to expect that pedestrians will automatically scatter out of their way?

I've been driving electric for two years and I have surprised exactly one pedestrian: a woman who was walking backwards into the driving lane of a parking lot while carrying on a conversation with someone across the lot. I stopped and waited for her to realize she was walking into an occupied traffic lane and she eventually saw us waiting for her. She was surprised, but I wasn't, and there was never any danger to anyone. She was clearly embarrassed by what she had been doing and tried to blame her reckless behavior on my quiet car. If I had been going fast enough that her foolishness could have created a dangerous situation, my car would have been making the same tire noise as any other car, which may or may not have been audible depending on the environment.

I'm quite sure that I don't need my neighbor's electric car waking me up at 5 am just because people are scared of unfamiliar technology. I propose that we solve a real problem, like driving while phoning or texting, before we rush into squashing a quiet car advantage in response to uninformed hysteria.

Nissan: Please give your drivers a manual way to alert pedestrians with something less obnoxious than a blast of the car horn. GM did this with the EV1 and owners loved it. Hold off on making a constant noise until there's enough research to show quiet cars are a danger and we have a validated way to improve the situation for all cars -- electric, hybrid, or gas-burning.

Edited July 5, 8:46 am: corrected technical error in description of Tesla's regen algorithm and clarified pedestrian surprise story.

Edited July 5, 3:20 pm: added update on more optimistic Leaf range numbers as reported by MotorTrend.


About this Entry

This page contains a single entry by Tom Saxton published on July 4, 2010 1:45 PM.

Electric Vehicle Range and Charging was the previous entry in this blog.

Tesla Roadster Charging Rates and Efficiency is the next entry in this blog.

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