Honva
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Re: B mode vs e-padel efficiency

Wed Apr 04, 2018 9:21 pm

Found this page from Nissan with more details on how e-pedal function.

https://www.nissan-global.com/EN/TECHNO ... Pedal.html

From the description, it appears that friction brake is not normally used until stop. Only engaged on slippery road.

It should have as good efficiency if not better. I am going to try more comparison test with more careful driving on b vs e-pedal.

Honva
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Re: B mode vs e-padel efficiency

Fri Apr 13, 2018 8:44 am

Ok, did more driving in e-pedal mode and here is my observation.

e-Pedal mode could be as efficient as B mode, if not more. What I observed is that e-Pedal do not apply the brakes if you don't let go the accelerator completely. Even, if you just leave the accelerator very slightly from complete release, the car will keep rolling until the last bit of momentum is consumed. When you car is very slow, it is like putting it in neutral. If you let go completely, brakes will engage.

So, if you want to gain efficiency, try moderate the speed with reduced pedal rather than let go completely. Only let go completely when the car almost fully stop to engage the brake to hold it. The manual although not explaining the details, also suggested not to let go completely but to moderate the pedal position. I have been able to get ~13Kwh/100km in bad stop and go city traffic in e-Pedal mode. Not bad at all.

I found that the major advantage of e-Pedal over B mode in traffic is that I could rest my foot instead of holding the brake pedal when stopped. Also, there is a convenience that when you put the car in gear, you do not need to do it twice to get to B mode. In e-Pedal mode, there is no difference between D and B.

Eco mode does not really save traction motor energy. It just give you a different response curve for the pedal range to promote slower acceleration. You can get the same slower acceleration with less foot movement. One area Eco mode save energy is that it seems to made the car use less of the resistive heater when you first start from cold. It will shut off the resistive heater earlier and relies more on the heat pump. Yes, it will take a little bit longer to warm up but you save a bit of power. When it is cold, I do now start the car in Eco mode and switch it off after it warms up a bit.

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IssacZachary
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Re: B mode vs e-padel efficiency

Fri Apr 13, 2018 9:39 am

Honva wrote:Eco mode does not really save traction motor energy. It just give you a different response curve for the pedal range to promote slower acceleration. You can get the same slower acceleration with less foot movement.

Sorry, I have to disagree.

Anytime you use regenerative braking you are turning momentum energy into electric energy AND heat energy. That's a loss of energy, an inefficiency, because nothing is 100% efficient. And the more regenerative braking you use the more energy you lose and the less efficient it is.

Try speeding up to 60mph/100kph and then slowing back down to half that many many times in B mode or E-Pedal mode and then try the same thing in D mode without ECO and then try it coasting in neutral and see which gives you the best miles/km per kWh.
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Honva
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Re: B mode vs e-padel efficiency

Fri Apr 13, 2018 10:06 am

IssacZachary wrote:Sorry, I have to disagree.

Anytime you use regenerative braking you are turning momentum energy into electric energy AND heat energy. That's a loss of energy, an inefficiency, because nothing is 100% efficient. And the more regenerative braking you use the more energy you lose and the less efficient it is.

Try speeding up to 60mph/100kph and then slowing back down to half that many many times in B mode or E-Pedal mode and then try the same thing in D mode without ECO and then try it coasting in neutral and see which gives you the best miles/km per kWh.


Unfortunately, not everyone lives in the desert where your car is the only moving object. Try the experiment you suggested in the city and the only two places you end up are either the hospital or police station. :D (Ah...I may be wrong! Could be in the morgue too). It is no different to say if we live in outer space, once I set in motion in the right direction, I can even turn the car off and go far far away!

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IssacZachary
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Re: B mode vs e-padel efficiency

Fri Apr 13, 2018 10:51 am

Honva wrote:Unfortunately, not everyone lives in the desert where your car is the only moving object. Try the experiment you suggested in the city and the only two places you end up are either the hospital or police station. :D (Ah...I may be wrong! Could be in the morgue too). It is no different to say if we live in outer space, once I set in motion in the right direction, I can even turn the car off and go far far away!

Well, if your only choice is to slam on the brakes, what's the point in asking about efficiency? Just keep slamming on them and be happy.

But for me, I know there's usually a happy medium between using as much inefficient regen braking as possible and letting the momentum bleed off efficiently. And I'm going to use that as best as I can within a reasonable limit to increase my efficiency.

This conversation is like pointing out that going slower, down to 12mph, is more efficient than driving faster and someone saying that since they live in the city and it is not possible to drive 12mph that their only choice is to drive around at 100mph.
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Honva
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Re: B mode vs e-pedal efficiency

Fri Apr 13, 2018 11:29 am

I guess you may have read the title of this thread wrong. This thread is about "B mode vs e-pedal efficiency", not "which mode is the most efficient" or "how people should drive". D mode is off topic.

Each mode has its benefit and the driver will choose based on the traffic condition. This is why Nissan include different modes in the car.

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IssacZachary
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Re: B mode vs e-pedal efficiency

Fri Apr 13, 2018 12:26 pm

Honva wrote:I guess you may have read the title of this thread wrong. This thread is about "B mode vs e-pedal efficiency", not "which mode is the most efficient" or "how people should drive". D mode is off topic.

Each mode has its benefit and the driver will choose based on the traffic condition. This is why Nissan include different modes in the car.

So the answer is NEITHER! Are you happy to know the answer?

If one provides less regen without causing you to need to use friction braking then theoretically it's more efficient. But then again it looks like they're practically the same. If there's a difference we're splitting hairs here. Both are inefficient and there's nothing you can do about it.

Sorry if it is too hard to comprehend how pointing out relevant comparisons with how other modes affect efficiency can help us all understand whether the e-pedal or the B mode could be more efficient than the other.

I'm not telling anyone how to drive nor what mode they should use. I am making a comparison. A comparison. Do you need to know the definition of a comparison? It's a way of illustrating a point. What's the point I'm making? That B mode could be a slightly more efficient than e-pedal. How do we know this? Through comparisons with other levels of regenerative braking!

There's no need to twist everything I say into that I'm some sort of city hating redneck that's using this thread to promote driving like an idiot when all I'm simply trying to do is illustrate the correct answer!
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Re: B mode vs e-padel efficiency

Tue Jul 24, 2018 5:02 pm

Hi everyone, looking into this old thread because I'm ordering a Leaf now. Just want to thank OP Honva for your testing.

IssacZachary you make good hypothetical points, but I think that one thing we should keep constant in this efficiency test is stopping distance, which in the case of most drivers, should be set at an acceptable city traffic distance. I think with OP's testing, e-pedal can achieve same or better B-mode efficiency with proper pedal throttling.

For highway driving, since you may have possibly infinite stopping distance, I agree with you. D is probably better. It looks like with e-pedal you can achieve D or even N level coasting with proper throttling to not activate the regen brakes, but nobody wants to hold it at a spot like that, so it would be better to go into D or N.

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Re: B mode vs e-padel efficiency

Tue Jul 24, 2018 5:38 pm

rchsun wrote:Hi everyone, looking into this old thread because I'm ordering a Leaf now. Just want to thank OP Honva for your testing.

IssacZachary you make good hypothetical points, but I think that one thing we should keep constant in this efficiency test is stopping distance, which in the case of most drivers, should be set at an acceptable city traffic distance. I think with OP's testing, e-pedal can achieve same or better B-mode efficiency with proper pedal throttling.

For highway driving, since you may have possibly infinite stopping distance, I agree with you. D is probably better. It looks like with e-pedal you can achieve D or even N level coasting with proper throttling to not activate the regen brakes, but nobody wants to hold it at a spot like that, so it would be better to go into D or N.


Yes. That's basically the point.

Stop as quickly as necessary, but no need to stop quicker.

I'm not sure which regen brakes more, e-pedal or B-mode, but yes, you can always "throttle" the regen.

The point about coasting to a stop isn't meant to mean that that's what you're supposed to do. It only illustrates the point that the less you brake, even regen brake, the more energy is conserved. It's like mentioning that 12mph is the most efficient speed to drive at. That doesn't mean everyone should drive at 12mph, but the closer you can drive to that speed, say 65mph instead of 70mph, the more efficient your driving will be.
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Stiemey
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Re: B mode vs e-padel efficiency

Wed Oct 10, 2018 9:10 am

I have done quite a bit of driving recently to test differing driving configurations:

B Mode - Eco Mode - e-Pedal - 1 Week
B Mode - Eco Mode - No e-Pedal - 1 Week
B Mode - No Eco Mode - No e-Pedal - 1 Week
B Mode - No Eco - e-Pedal - 1 Week
D Mode - Eco Mode - e-Pedal - 1 Week
D Mode - Eco Mode - No e-Pedal - 1 Week
D Mode - No Eco Mode - No e-Pedal - 1 Week
D Mode - No Eco - e-Pedal - 1 Week

For my test purposes only, I drive 19.5 miles each way to and from work. Of the 19.5 miles, approximately 2 of them are city streets, the rest is highway. Now, in my city, highway can be almost full speed the whole way one day and stop and go the next (people cannot drive here for nothing!) Here are my conclusions on my driving habits:

1) B-Mode with Eco on and e-Pedal off is the most efficient.
2) Not using the Propilot Assist is the most efficient.

1a) Switching on the e-Pedal as I am exiting the highway improved efficiency
2a) The problem with the Propilot Assist is that once traffic in front clear, it will floor the accelerator to catch up and slams on breaking to slow down as traffic does. Not using Propilot Assist, I am able to gradually increase speed when traffic clears and can anticipate slowdowns ahead keeping off the friction braking completely.

Just my 2 cents and wanted to share for anyone who may have a similar drive.

Cheers,
Eryk

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