Miles per kWh not making sense to me

Miles / kWh not making any sense to me.

I have a 2019 40kwh Leaf, and I drive in Seattle Washington. The way I check my range performance is to divide miles driven by battery percentage used.

For Example: I recently charged to 100% and immediately drove 137 miles, about 2/3 freeway at 60 mph and the rest around 45 mph on secondary roads. At the end of this trip the remaining battery registered 12%. So I figure 137 divided by 88 (percentage battery used) = 1.55. Or 155 miles of range had I driven the car all the way down to 0%.

Whenever I drive in temperate weather with no rain, and no need to use cabin heating or air conditioning I get 1.49 to 1.55 miles per 1 % of battery. In other words spot on Nissan’s claim of 150 miles from a 40 kWh battery.

But if I look at my Leaf’s Miles per kWH meter it typically shows 4.7 to 5.1 m/kWh for the same driving in temperate weather with no cabin heat/air conditioning. At the low end of 4.7, my Leaf would only be using 32 kWh of a full battery to produce 150 miles. At 5.1 kWh my car would only utilize 29.4 kWh. I would think a 40 kWh battery manages itself so that at least 35 kWh is dedicated to driving the car. If so that would produce 178.5 miles of range.

What gives??

Thanks for listening, Scott Newcombe

Your numbers sound about right to me based on my 2017 S with a 30kWh battery.

I'd guess the discrepancies are due to a combination of factors including

- the odometer is probably optimistic so the kWh/mi is probably optimistic too
- there is some reserved beyond 0% SOC that isn't being taken into account, LeafSpy might show this
- as you mentioned the battery is 40kWh nominal and not all 40kWh are available to more the car

Bottom line, your car sounds fine and the instrumentation is just not that accurate.

I think the explanation is that you didn't reset your miles/kWh stats before starting the trip.

That value is averaged out since the last reset, so it includes all the stop and go city driving, where the LEAF is super efficient.

Next time you take a similar trip, reset that miles/kWh metric and you should find that, at the end of the highway trip, your miles/kWh is closer to 4 miles/kWh (155 miles / 38 kWh)

minitoleaf said:

Miles / kWh not making any sense to me.

I have a 2019 40kwh Leaf, and I drive in Seattle Washington. The way I check my range performance is to divide miles driven by battery percentage used.

For Example: I recently charged to 100% and immediately drove 137 miles, about 2/3 freeway at 60 mph and the rest around 45 mph on secondary roads. At the end of this trip the remaining battery registered 12%. So I figure 137 divided by 88 (percentage battery used) = 1.55. Or 155 miles of range had I driven the car all the way down to 0%.

Whenever I drive in temperate weather with no rain, and no need to use cabin heating or air conditioning I get 1.49 to 1.55 miles per 1 % of battery. In other words spot on Nissan’s claim of 150 miles from a 40 kWh battery.

But if I look at my Leaf’s Miles per kWH meter it typically shows 4.7 to 5.1 m/kWh for the same driving in temperate weather with no cabin heat/air conditioning. At the low end of 4.7, my Leaf would only be using 32 kWh of a full battery to produce 150 miles. At 5.1 kWh my car would only utilize 29.4 kWh. I would think a 40 kWh battery manages itself so that at least 35 kWh is dedicated to driving the car. If so that would produce 178.5 miles of range.

What gives??

Thanks for listening, Scott Newcombe

Click to expand...

Are you using LEAF Spy?
Answer; no because LEAF Spy would never display 100% in any normal situation.

https://daveinolywa.blogspot.com/2020/06/e-plus-summer-range-test.html

The GOM displays usable range with a heavy does of Nissan conservatism. It ranges from 100 to zero % but as we should know, the car does not stop dead in its tracks when it hits zero %. In fact, it doesn't even go into turtle mode and your LEAF has as much energy in it as the Gen One LEAF had at the first low battery warning.

Now if that is all there is, we could work with that. But the GOM isn't linear. LEAF Spy shows actual SOC which means you not only never see 100%, you won't see zero % either since both would be highly detrimental to the pack and even Nissan was smart enough to avoid that.

So I did a range test recording each tick of the GOM from 100% to Zero. LEAF Spy went from 98.3% to 8%

The TLDR version

https://docs.google.com/spreadsheets/d/1Vs3HYM9gTwcrJHSz427Z1oR8a5djVaXMgPL3axm08qY/edit#gid=0

Tidbits

SOC match at 88%

Range match at 59% GOM, 63% LEAF Spy

FYI; I drove 177 miles from Yakima over Chinook Pass to Centralia on a single charge in my 40

That is impressive mileage for a 40 KWh leaf. May I ask what kind of highway/speed conditions you had. Next spring depending on events we may be bringing a 2018 or 2019 40 KWh leaf from LA to BC. Curious how that’s going to go. . Planning on doing it in 4 days so no rush.

***That is impressive mileage for a 40 KWh leaf. May I ask what kind of highway/speed conditions you had. Next spring depending on events we may be bringing a 2018 or 2019 40 KWh leaf from LA to BC. Curious how that’s going to go. . Planning on doing it in 4 days so no rush***

The highway driving was mostly 60 mph and occasionally 65 mph, along I5 in Western Washington State. I stayed in the right lane and had company from other drivers who did not join the 80 mph demons jockeying in the other lanes. Again, this particular trip was 137 miles and ended with the battery display showing 12% charge left. The non freeway driving was typically 45 to 55 mph and covered about 1/3 of the journey. The weather was dry and about 55 degrees F.

For what it is worth my Leaf (SV model) has always shown me 150 mile range in benign weather. Sometimes a bit better than 150. During the colder winter weather it drops quite a bit. Then the range is 110 to 120 miles. Lots of rain, use of cabin heat, cold temps certainly have an effect. When calculating range I ignore GOM. And since I can't make the Leaf's "Miles Per kWh meter" pencil out to something sensible I ignore it as well.

Best of luck with your LA to BC Leaf adventure. I really like this car and won't ever go back to driving a internal combustion vehicle.

webeleafowners said:

That is impressive mileage for a 40 KWh leaf. May I ask what kind of highway/speed conditions you had. Next spring depending on events we may be bringing a 2018 or 2019 40 KWh leaf from LA to BC. Curious how that’s going to go. . Planning on doing it in 4 days so no rush.

Click to expand...

Agreed - my 2012 Leaf will not do much better than 4 miles/kWh under the most favorable conditions of a mix of suburban with some 60-65 mph highway - sort of "milking it". I use LeafSpy set a 4m/kWh and the range estimate is always about spot on when climate control is off - over thousands of miles of this "mix". I've never been able to approach mid to high 4's under any conditions. I don't use heat and use of A/C during summer will knock it down to the mid to high 3's (m/kWh).

Of course, the actual range will be mostly influenced by the status/health of the battery, which is quite well defined by LeafSpy!

Are you resetting the trip meter each time ?

Marktm said:

webeleafowners said:

That is impressive mileage for a 40 KWh leaf. May I ask what kind of highway/speed conditions you had. Next spring depending on events we may be bringing a 2018 or 2019 40 KWh leaf from LA to BC. Curious how that’s going to go. . Planning on doing it in 4 days so no rush.

Click to expand...

Agreed - my 2012 Leaf will not do much better than 4 miles/kWh under the most favorable conditions of a mix of suburban with some 60-65 mph highway - sort of "milking it". I use LeafSpy set a 4m/kWh and the range estimate is always about spot on when climate control is off - over thousands of miles of this "mix". I've never been able to approach mid to high 4's under any conditions. I don't use heat and use of A/C during summer will knock it down to the mid to high 3's (m/kWh).

Of course, the actual range will be mostly influenced by the status/health of the battery, which is quite well defined by LeafSpy!

Click to expand...

You actually probably are unless you conform to the 36 PSI mandate. If you are not resetting the meter daily, you really don't know how you are doing. The day to day variance can be quite large.

Thanks to several of you who advise reseting meters. I don't always do this, although on the specific trip detailed in my post, both the "miles per kWH" metric and the trip meter were reset. So the values I got for those two readings were unique to this single 137 mile journey.

There has been some talk in the forum about a battery reserve in the 40 kWh LEAFs.
I don't know specifics, or whether the reserve is accumulated as the SoC drops (the Tesla way.)

Just curious - what are the initial amp-hours on the 40 kWh battery? The 24 kWh seemed consistent slightly above 66. However, that seemed to drop quickly to about 64.

My battery log for reference.

Marktm said:

Just curious - what are the initial amp-hours on the 40 kWh battery? The 24 kWh seemed consistent slightly above 66. However, that seemed to drop quickly to about 64.

My battery log for reference.


battery log 9.17.20.jpg

Click to expand...

The 40 kwh packs were the first to not have a very narrow range of full charge statistics. The range of new ahr numbers peaked around 115 so you could be slightly over that or as much as 1 below that.

DaveinOlyWA said:

The 40 kwh packs were the first to not have a very narrow range of full charge statistics. The range of new ahr numbers peaked around 115 so you could be slightly over that or as much as 1 below that.

Click to expand...

Thanks Dave;

I realize that the following is anecdotal for the "24" kWh battery and assumptions about the "40" kWh, but is a quick grosso-modo calc that is mainly to determine if anyone has more accurate numbers that would be based on the correct Li chemistry/cell arrangement and a standard energy capacity method:
"24"kWh battery => 66.14 amp-hours x 375 Volt DC* = approx equiv. to 24.8 kVAh or kWh
"40" kWh battery => 115 amp-hours x 375 Volts DC** = approx equiv. to 43.1 kVAh or kWh

* - This is a guestimate average from my several years of logging
** -Does anyone have this data as cell arrangement and chemistry are likely different?

Marktm said:

DaveinOlyWA said:

The 40 kwh packs were the first to not have a very narrow range of full charge statistics. The range of new ahr numbers peaked around 115 so you could be slightly over that or as much as 1 below that.

Click to expand...

Thanks Dave;

I realize that the following is anecdotal for the "24" kWh battery and assumptions about the "40" kWh, but is a quick grosso-modo calc that is mainly to determine if anyone has more accurate numbers that would be based on the correct Li chemistry/cell arrangement and a standard energy capacity method:
"24"kWh battery => 66.14 amp-hours x 375 Volt DC* = approx equiv. to 24.8 kVAh or kWh
"40" kWh battery => 115 amp-hours x 375 Volts DC** = approx equiv. to 43.1 kVAh or kWh

* - This is a guestimate average from my several years of logging
** -Does anyone have this data as cell arrangement and chemistry are likely different?

Click to expand...

Most calculations I have seen is using 360 volts

DaveinOlyWA said:

Most calculations I have seen is using 360 volts

Click to expand...

Yep
And then knock off ~ 2 kWh for top and bottom unusable reserves to protect the battery

SageBrush said:

DaveinOlyWA said:

Most calculations I have seen is using 360 volts

Click to expand...

Yep
And then knock off ~ 2 kWh for top and bottom unusable reserves to protect the battery

Click to expand...

Sounds like you are mistaking reasonable and logical battery management with Nissan? The total of top and bottom is just over 2 kwh

DaveinOlyWA said:

The total of top and bottom is just over 2 kwh

Click to expand...

Yes, that is what I meant.