Coasting consumes a kilowatt - crazy

[TickTock]

Interesting observation this morning. I don't usually do this, but on a whim, I threw the Leaf into Neutral to coast up to a stop sign (there was noone behind me and I was in a mellow mood ). Anyway, I was surprised to see that I was still consuming 1kW of power. It doesn't show up in the Energy Screen Nissan provided but I monitor the actual battery power out with CANary. Once the car came to a complete stop, the power dropped to zero (whether in Neutral or Drive) so it wasn't headlights, heater, etc. I was surprised so I repeated the experiment several times. The lowest power I ever saw while the car was moving in neural was 0.87kW but it does go to zero at a stop. So it appears even when in neutral, the inverter is still powered and burning a non-negligible amount of power. I can't think of any reason not to shut down the inverter in neutral since regen is also disabled and they clearly can turn it back on quickly enough when you touch the accellerator from a stop.

 

[mkjayakumar]

Thats interesting, because I have seen that I am able to get the highest efficiencies by coasting in N (rather than any regen), which led me to believe that there is hardly any energy spent just free wheeling. I haven't observed any Gid value coming down either during coasting, but maybe I haven't looked hard enough.

 

[TomT]

Odd since there is a long hill near me that I often cost down in N and when I do so (assuming only the entertainment systems is on and no lights or CC) I typically see a power draw of about .2 Kw on my meter... It's a fairly noisy reading but that is about the average...

 

[TickTock]

Odd since there is a long hill near me that I often cost down in N and when I do so (assuming only the entertainment systems is on and no lights or CC) I typically see a power draw of about .2 Kw on my meter... It's a fairly noisy reading but that is about the average...

What kind of meter are you using?

 

[TomT]

A Lincomatic version 1.3.

Odd since there is a long hill near me that I often cost down in N and when I do so (assuming only the entertainment systems is on and no lights or CC) I typically see a power draw of about .2 Kw on my meter... It's a fairly noisy reading but that is about the average...

What kind of meter are you using?

 

[Nubo]

Did you invoke Neutral directly, or by the trick of shifting to Reverse?

Just wondering if that makes any difference in how the inverter behaves.

 

[TickTock]

TomT, what year is your Leaf? Mine is 2011. My code averages the power over each second so no noise. How hard would it be to get Lincomatic to add a longer averaging interval? No CC or radio, etc (power does go to zero once stopped).

I used the shift to Reverse trick. I'll try the other way tonight.

 

[Stoaty]

I have seen this frequently. Sometimes the power is extremely low, sometimes around 1 kw. This is with a genuine Gid Meter (TM). I always shift to neutral with the reverse trick. Will have to try the other way.

 

[DarkStar]

I've noticed this behavior with my WattsLeft meter also. I'm not sure what's using all the power, but now I just use the accelerator to manage the coasting...

 

[Stoaty]

I've noticed this behavior with my WattsLeft meter also. I'm not sure what's using all the power, but now I just use the accelerator to manage the coasting...

I have noticed the same phenomenon when using the accelerator to manage the coasting. If you are not consuming power or in regen (as shown on the energy screen on the Nav) you will still be using a bit of power. I have to take it one notch down, so it looks like there is a tiny bit of regen in order to show no (or very little) power usage on my Gid meter.

 

[lincomatic]

TomT, what year is your Leaf? Mine is 2011. My code averages the power over each second so no noise. How hard would it be to get Lincomatic to add a longer averaging interval? No CC or radio, etc (power does go to zero once stopped).

I used the shift to Reverse trick. I'll try the other way tonight.

TickTock, how are you calculating kW? I'm just multiplying packvolts * packamps. I don't do any averaging .. just instantaneous value updated about every 250ms. I get the same low 0-.2kW readings whether coasting in neutral (via reverse trick) or just sitting in my driveway.

 

[TomT]

Mine is an early 2011.

Actually, I rather like the fast response as I can see things happening more quickly and dynamically, such as with regen... The noise is only an issue at very low power levels below 500 watts or so. I use the R trick for Neutral...

TomT, what year is your Leaf? Mine is 2011. My code averages the power over each second so no noise. How hard would it be to get Lincomatic to add a longer averaging interval? No CC or radio, etc (power does go to zero once stopped). I used the shift to Reverse trick. I'll try the other way tonight.

 

[fcleaf]

Has this been answered? Did you retry the test in both modes of entry? (better yet, what is the other way to enter N in motion other than reverse? I'm a new to leaves)

Thanks!

 

[91040]

If you hold the shifter in the left most position for a second or two, you get to neutral.

 

[fcleaf]

Thanks for the answer on getting into Neutral.

Did anyone figure out if it keeps the motor engaged in neutral?

 

[LEAFfan]

TomT, what year is your Leaf? Mine is 2011. My code averages the power over each second so no noise. How hard would it be to get Lincomatic to add a longer averaging interval? No CC or radio, etc (power does go to zero once stopped).

I used the shift to Reverse trick. I'll try the other way tonight.

TickTock, how are you calculating kW? I'm just multiplying packvolts * packamps. I don't do any averaging .. just instantaneous value updated about every 250ms. I get the same low 0-.2kW readings whether coasting in neutral (via reverse trick) or just sitting in my driveway.

I coasted in N for .5 miles and according to the LEAF App I used 18 Whs.

 

[kubel]

Not sure if it's true (or if this even makes sense), but the sensation I get from "coasting" is that neutral is emulated. In the words of Senator Vreenak, "IT'S A FAAAAAAKE!!!" It *feels* to me as if the car is attempting to provide power to the motor, ever so slightly, when I coast in neutral. It doesn't feel right. Think of attempting to emulate neutral while doing 30MPH in first gear of a manual transmission car without pressing the clutch. You would do so by pushing the gas to emulate that free neutral feeling, otherwise the engine will slow you down quite rapidly if you lift off the gas. That's how it feels to me, as if the car is faking neutral. Make sense? No? Ok, nvm.

 

[planet4ever]

Thanks for the answer on getting into Neutral. Did anyone figure out if it keeps the motor engaged in neutral?

The motor is always engaged. There is no transmission in the car, no clutch and no gears that ever shift position. Not for neutral, not for reverse, not for anything. There is only a reduction gear train and a differential.

The only thing that should be happening in neutral is that the magnetic fields should be "disengaged", but since the magnets are in the rotor there are always magnetic fields moving around if the car is moving. So the trick it to make it so that no electric currents can be induced in the windings or anything else conductive around the motor. Not being an EE I have no real concept of how hard or easy that might be.

Ray

 

[fcleaf]

I coasted in N for .5 miles and according to the LEAF App I used 18 Whs.

Any idea how much power would be used or regenerated when you take your foot off the "gas" for that same .5 mile in Drive mode? What is the final speed on the same stretch using N vs D with foot off the accelerator?

I'm asking because I have used neutral for years in my hybrid to gain about 5-8 mpg average. I'm wondering if it would be more efficient in the Leaf to coast in N, D, or to use Regen Braking and hold the accelerator down until closer in. The guy at the dealership looked at me like I was a nut when I asked him how to put the car in N while driving. He said it would defeat the whole purpose of the regen system and would be less efficient. Curious if he is right, and I don't own the car yet to test it myself. I absolutely loved the 24 hour testdrive though.

Kubei, your feel of a "faked" neutral makes sense based on the statement that Ray made about not having any trany/gears to disengage. Thanks for the observation.

Cheers

 

[EVDRIVER]

You guys are really worried over something you can't change. The car does have variable parasitic loads at a stop and possible additional draw when coasting can easily increase on other systems that may have higher loads at higher speeds. I never use neutral since I can do it with my foot and I can regain any 1kw loss in regen without slowing the car to were it matters, I can see this in real time. There are much better ways to drive an EV than coasting, this is a non-issue if you can drive properly and use "D". If you can't then you can age faster worrying over 1Kw and wind drag limits.