Range Info, Pedal Behavior and Artificial Noise

I think there are three things that Nissan could be doing better with the Leaf: providing clearer, more accurate range info, taking full advantage of regenerative braking from the accelerator pedal, and holding off on making constant artificial noise.

More details on my blog here: http://www.saxton.org/tom_saxton/2010/07/3-ev-lessons-for-nissan.html

Tom, excellent, informed and well thought-out. I hope someone at Nissan is listening. IMHO they could significantly improve their chances of success with the Leaf by taking your specific advice.

Or....we can continue to make it up as we go, just between ourselves!

From a marketing standpoint - +1 for jumping on a forum and getting people to read your blog.

Nissan: Get real range numbers out there now.

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I generally agree, but think the 'range abuse' blog posts are unnecessary. The company just had a bunch of drive time with pre-production cars. I don't know if they have a full production vehicle on any roads yet. Therefore, they CANNOT give any of us 'real' range numbers today. Eventually we will. I don't recall Tesla publishing real-world range numbers until they had production cars on the road. Yes - they have plenty of info and charts available today. And in a year or two we'll have the same for the Leaf.

Regen on the accelerator pedal: I absolutely do not want the car to have regen on the accelerator pedal. I plan to drive this car - this is going to be my primary daily driver. This is not a sports car, or something with obscure 'personality quirks' that I'll put up with in order to enjoy0-60 in 3.9 seconds. I want the car to go when I stop on the accelerator pedal. I want it to coast or have very light 'engine braking like' regen when I'm off the accel pedal. I want 'real' breaking to happen when I touch the brake pedal and not before. I do not want foot cramps because I'm trying to feather the accel pedal to feel the different modes.

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.

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While it's true that friction brakes equals lost energy, there is no reason to expect that the friction brakes will be part of the brake equation during the first portion of brake pedal travel. It's easy enough to start with regen then bring friction in as more pressure is applied to the brake pedal. In addition, coasting is much more efficient than regen.

Nissan has yielded to the hysterical calls to add noise to electric vehicles.

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One might not agree with the calls to assist folks with vision problems, but Nissan is in the car business and has to comply with the laws in place (or expected to be in place) when they bring their product to market. Not complying means they cannot sell the car. Rail against the politicians or start a lobbying organization of one feels so inclined, but pushing against Nissan is misplaced. Before doing anything, though, put on a blindfold and take a walk. It'll open your eyes, so to speak...

With respect, Tom, your points might be useful if Nissan was courting Roadster owners for the Leaf. Since we know that's not the target market, I think Nissan is absolutely on the right track. They need to court ICE drivers. It's not in their best interest to require transition training. There is already enough public perception that EVs aren't 'normal' - it's in Nissan's best interest to be very conservative with this vehicle or they might not get another chance.

Andy

Technically, there is no need for a brake pedal, but to take one's foot off "the" speed-control pedal and have it spring loaded to "jump" to a "full, strong braking" condition is NOT SAFE.

So, if there is one pedal, it must "spring-return" (foot off) to a neutral point, neither go-faster nor go-slower.

So, a two pedal system is commonly used, so that there is:

1. A very "safe" division between suddenly going faster and suddenly going slower. It must be an intentional movement of the foot, not just a slip, bump in the road, etc.

2. There are times when driving with the mechanical brakes engaged AND one foot on the go-faster is needed: primarily useful when starting up on a steep hill. There is no mechanical "emergency" or "parking" brake to use in the LEAF, I believe.

AndyH: I thought exactly like you until I drove the Roadster. I thought having more regen on the accelerator than the light feel of the RAV4-EV was a bad idea, until I tried it. But it's really great. It's not strong enough to be startling, but it is enough to slow you down most of the way as you approach a stop light if you're paying attention. It's really outstanding driving down a hill and holding a steady speed by allowing just enough regen. It doesn't take some uncomfortable effort to hold a steady speed, after a little while you don't even think about it.

garygid: The regen level is not "full strong braking", it's more like soft braking and very smooth. There is still a brake pedal for strong braking. When you need to slow or stop in a hurry, you push on the brake pedal, just like any other car. All of the gas cars I've driven have required me to keep my foot on the pedal to hold a steady speed, so it's really no different on the Roadster except I can hold a steady speed on a road that goes up and down hills without shifting my foot between the two pedals. It's also an improvement to be able to slow down at an appropriate rate as you approach a traffic light or exit onto a long off ramp without wasting any energy on the friction brakes. On a short off-ramp, or if you wait until you're too close to a traffic light, you use the brake pedal just as you'd expect.

Driving up a steep hill is actually much easier in an electric car. The problem with a gas car is that it has no torque at low RPMs, so it's a real pain on a hill where you have to use the brake to hold your position while you quickly build up enough RPMs to have enough torque to climb a hill. In an EV, you get full torque at very low RPMs, so it's easy to just move your foot from the brake pedal to the accelerator and give it just enough juice to move you up the hill. It's a real joy to be able to easily start going up a steep hill and have full control over your speed. In a gas car, you have to do some trickery with the brakes, then you end up lurching forward; in an electric you just smoothly glide up the hill. This is just as true in our RAV4-EV as in the Roadster, so I expect it will be the same in the Leaf.

tomsax said:

I think there are three things that Nissan could be doing better with the Leaf: providing clearer, more accurate range info, taking full advantage of regenerative braking from the accelerator pedal, and holding off on making constant artificial noise.

More details on my blog here: http://www.saxton.org/tom_saxton/2010/07/3-ev-lessons-for-nissan.html

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From the blog ...

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.

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But, if you take a look at information Nissan has given, this kind of driving seems to actually give 105 miles ragne in Leaf (see scenario 10).



As to regen, I think there are valid reasons why people prefer one over the other. I suspect, people in geologies like ours with few flat roads and endless hills will prefer regen on accelerator pedal. It would be interesting to see how this works out in the years to come.

In anycase, I think whatever they have now can't be changed. Too late for that. Also, we need to await more test drive reports on how the eco mode works ...

The low speed noise is indeed puzzling. Apparently the talks have been going on for sometime - without involving anyone from EV community. This amendment passed in the Senate/House committee working on Driving Safety act unanimously. Japan already has laws on books to make the noise mandatory. So we are kind of losing the battle here ...

evnow said:

But, if you take a look at information Nissan has given, this kind of driving seems to actually give 105 miles ragne in Leaf (see scenario 10).

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I hadn't seen that chart. In the Roadster and RAV4-EV, the A/C gives about a 10% penalty on range, so I was interpolating Scenario 9 to a generous 80-mile range without A/C.

Is that chart on Nissan's site somewhere? I looked and didn't find it. Scenario 10 surprises me, but it's great news if it's reproducible. I'd love to have a link to that chart with its original source.

evnow said:

As to regen, I think there are valid reasons why people prefer one over the other. I suspect, people in geologies like ours with few flat roads and endless hills will prefer regen on accelerator pedal. It would be interesting to see how this works out in the years to come.

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I think it's difficult to really grasp the benefits of significant regen on the accelerator pedal until you've driven with it for a few days. I realize not everyone will share my opinions about the driving experience, but I have a hard time being convinced by someone saying they prefer what they are used to without ever having tried the alternative. I hear nothing but praise from Tesla owners about how Tesla did it. I know a good number of Tesla owners who are not sports car fanatics but just interested in supporting the company that was pioneering production EVs, so I think it's a mistake to dismiss the opinion of Tesla owners as somehow being different from everyone else.

I just found out that regen is even stronger on the MINI E vehicles from the one-year test drive lease program, and those drivers seem to be at least as enthusiastic about how the MINI E drives as Tesla drivers are about the Roadster.

mwalsh said:

With respect, Tom, your points might be useful if Nissan was courting Roadster owners for the Leaf. Since we know that's not the target market, I think Nissan is absolutely on the right track. They need to court ICE drivers. It's not in their best interest to require transition training. There is already enough public perception that EVs aren't 'normal' - it's in Nissan's best interest to be very conservative with this vehicle or they might not get another chance.

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Which of the following is going to sell more Leafs?

1. "The Leaf drives just like a gas car, except it has limited range. If you want to reduce your impact on the environment and reduce our dependence on foreign oil, and the range meets your driving needs, you should consider buying a Leaf."

2. "Driving a Leaf is a big improvement over driving gas. Now that I'm used to the electric experience, I greatly prefer it to driving gas burners, plus it's better for the environment and reduces our dependence on foreign oil. If the Leaf's range meets your driving needs, you should run out and buy one now."

I want the Leaf to be as awesome as it can be, for owners to be enthusiastic about how much better it is to drive electric, and for that enthusiasm to sell more Leafs and bring EV appreciation to mainstream buyers.

I suppose people will snort that I'm not a "real" driver, but as I have gotten older, and migrated to more modern cars, I find that I use cruise control quite a bit on the freeway except when traffic is heavy. I'd be interested in hearing how much regen people think should be in effect with cruise control in hilly driving. (Gary, you are excused from this discussion, since I know you believe in freewheeling down hills, apparently no matter how fast you end up going at the bottom!)

I ask because my non-hybrid Honda Civic seems to hold speed pretty well going down hill with cruise control on, though of course it is using engine braking rather than regen. But my wife's gen 2 Prius almost seems to freewheel down hill with cruise control on. Of course it doesn't freewheel in "B" shift but, to my surprise, it refuses to use cruise control in that mode. Prius "B" shift seems to work much like what tomsax describes for the Tesla, with heavy go-pedal moderated regen.

Clearly what I would like to see is cruise control moderated regen when going down hill.

tomsax said:

evnow said:

But, if you take a look at information Nissan has given, this kind of driving seems to actually give 105 miles ragne in Leaf (see scenario 10).

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I hadn't seen that chart. In the Roadster and RAV4-EV, the A/C gives about a 10% penalty on range, so I was interpolating Scenario 9 to a generous 80-mile range without A/C.

Is that chart on Nissan's site somewhere? I looked and didn't find it. Scenario 10 surprises me, but it's great news if it's reproducible. I'd love to have a link to that chart with its original source.

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Thats my chart - but compiled from various sources describing the presentations given by Nissan during the Yokohama test drive event, as noted. See this thread for details.

http://www.mynissanleaf.com/viewtopic.php?f=4&t=562

Yes, it is surprising that all of Nissan's scenarios without AC/Heater seem to give above 100 miles and with AC/heater below 70. I remember a comment by Perry specifically mentioning AC as the culprit in range reduction.

planet...
Your exaggeration (or misinformation) about my desire for useful, economic foot-off, no-regen coasting, mostly on the (almost) flat, is ... very much NOT my opinion.

I suspect that Nissan cares little about Tesla's "innovations", or about my opinion. Likely they want the driving-control experience to be as "normal" and consistant as possible, in a large part for "legal liability" reasons. They might want to be more innovative, but at this early point of entering a "hostile" marketplace, they probably feel that they should not.

But, since some people think Tesla's "more regen on the go-faster pedal" should be tried before it is rejected, I will suggest that the same applies to the uses and brnefits of "coasting".

I (and many, perhaps even most of us here) can adapt to just about any system of controls, including steering with the feet (rudder), and stopping with a "parking brake" lever. Many other people, like my wife, might be able to adapt (I am sure she COULD), but they do not WANT to HAVE to do it to be able to drive a new car. If the "driving" is unfamiliar, WE might like the challange, but SHE will NOT like it.

The technical solution is simple: allow for variable Regen (braking) on both pedals (and foot-off), and program the "slowing" profile to fit the user. Then, everybody's preferences could be accommodated.

However, there is a real safety (and liability) issue with somebody getting into a car with an unknown braking function distribution and profile.

I might suggest that Tesla owners TEND to be ones who want to GO unless they HAVE to stop. This kind of driver might not be so interested in using "hypermiling" techniques, or gentle "coasting" toward the next red light.

If one is concerned about energy conservation, they will find "coasting" (without braking) useful, and also a very peaceful and "gentle" way to drive.

And, without making noise (or smog, or other pollution) is BEST, I believe.

You might enjoy trying it.

Very, very nice job, Gary.

garygid said:

planet...
If one is concerned about energy conservation, they will find "coasting" (without braking) useful, and also a very peaceful and "gentle" way to drive.

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Agree 100%. I started driving my V6 Camry that way about a year ago while waiting for an electric car. I get 28 MPG that way (combined Highway and City), and it is a lot more relaxing. I often see people speed past me just to stop at the light and find myself passing them in another lane after the light turns green.

Sorry ... but I am in the tomsax regen camp, and we'll just have to agree to disagree. And I have been in *both*/all camps (regular ICE, stick, automatic, hybrid hypermiling (for three weeks on a Prius rental, regular ICE hypermiling, etc). For the LEAF I'd love an adjustable regen, much of which (or as much as Nissan can program it) comes from the "go pedal". ( I realize it's too late to go completely Tesla or MiniE style (even if just from a technical perspective), but regen with lift-up/lift-off of the go pedal would be appreciated, and without the penalty of the "Eco" mode limiting acceleration. ) I won't further argue the pros/cons ... I'll just (try to :| ) wait patiently until Test Drive time.

garygid said:

planet...
Your exaggeration (or misinformation) about my desire for useful, economic foot-off, no-regen coasting, mostly on the (almost) flat, is ... very much NOT my opinion.

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Sorry, Gary, I didn't mean to step on your toes. I definitely should have put a smiley on that "excused" statement. I'm also quite relieved to see the "(almost) flat" qualification.

Stoaty said:

Agree 100%. I started driving my V6 Camry that way about a year ago while waiting for an electric car. I get 28 MPG that way (combined Highway and City), and it is a lot more relaxing. I often see people speed past me just to stop at the light and find myself passing them in another lane after the light turns green.

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Hypermilers call that "a reverse pass". And you can do that to someone 2 or 3 times in a ROW and they'll never notice. They will still jam the gas and then jam the brake while you smoothly glide along. It's actually sad how clueless some drivers are.

Stoaty said:

Agree 100%. I started driving my V6 Camry that way about a year ago while waiting for an electric car. I get 28 MPG that way (combined Highway and City), and it is a lot more relaxing. I often see people speed past me just to stop at the light and find myself passing them in another lane after the light turns green.

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Oh, yes, I definitely agree with that practice. My comments were directed to freeway driving in the mountains where I might well be traveling at the speed limit.

Jimmydreams said:

It's actually sad how clueless some drivers are.

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You should give them a high-five wave each time you pass them

Stoaty said:

Agree 100%. I started driving my V6 Camry that way about a year ago while waiting for an electric car. I get 28 MPG that way (combined Highway and City), and it is a lot more relaxing. I often see people speed past me just to stop at the light and find myself passing them in another lane after the light turns green.

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Me too. When I see a light turning red ahead of me I lift off the accelerator - it saves energy and saves the brakes - but the best part is that just about the time I have to start putting on the brakes the light often turns green again and I just continue on ahead in the other lane. Inevitably there's some poor noob who has to pass me so they can zoom ahead and screech to a stop at the light - and by the time they start back up again I've already glided on past them :lol: Sometimes, too, there are people who seem to notice how I usually come out ahead by driving intelligently, because they tend to switch to my lane and follow behind me

Personally, I would prefer that the Leaf will be able to have a pure coasting option, with regen only on the brake pedal. This is one thing I don't like about automatics is there's always that small amount of engine braking so I can't truly coast (of course, shifting into neutral works, but the transition from neutral to drive is suboptimal). But it's really not that big of a deal - wind resistance will slow you down anyway. True, I haven't tried the Tesla method - but that strikes me as potentially unsafe (what if your foot slips off the go pedal for a moment and there's a tailgater behind you). It's also something that would require a learning curve for most people (a big no-no when you're marketing a vehicle for the masses).

On the Tesla, when do the brake lights come on?