Basic mileage calculations - what am I missing?

I purchased a 2018 Leaf in November, and I pretty much expected low miles per kilowatt hour due to running the heat in the winter. No biggie since my work commute is only 6-7 miles each way. Anyway, the math seems to work as I've averaged about 3 miles per kilowatt hour through the winter. On the edge of spring, I'm expecting to see the numbers increase, and they have. I've averaged about 3.3 miles during March, and expect peak performance in spring (and again in fall) as there should be little or no need for heat or AC.

Here's where it gets weird. I took my first relatively longer trip on March 20th. I had a fully charged battery (40 kWh) with an estimated range of 135 miles (since it was still a bit cool and I was running the heat). Granted it was highway miles mostly, so not much regeneration going on, but my app says I averaged 3.3 miles / kWh on a roughly 58 mile trip, yet my estimated remaining mileage was down to 47 (roughly 35% battery remaining). I was forced to charge on the way home for fear of running out of electricity. I charged up an additional 7 kWh at a local department store (L2 charge for about an hour or so), and was able to make it home with 11 miles remaining (under 10%, which I know I am supposed to try to avoid getting that low).

The app says I averaged about 4 miles/kWh on the return trip (temp warmed up that day from low 40s in the am to upper 50s for the trip home, so no need for the heat). The total trip was around 120 miles (with the side trip to the department store), so these numbers just don't add up. What am I missing? Even with the conservative estimate of 3.3 miles/kWh, 47 kWh of battery charge should have netted me 155 miles, no? Am I just misunderstanding the battery capacity? I'm guessing now all kWh are created equal?

I'd like to have a better idea of real mileage available, as I was hoping to do some 200-300 total mile trips this summer with a couple of recharges along the way. I know the AC will drag down mileage, but this is my first summer with it, so I'm not sure if the loss is comparable to the heat in the winter or not. I do have other vehicles available for the longer trips, so am I just expecting too much to be able to drive this vehicle that far? Again, not a biggie, since the bulk of my travels are commuting 12-14 miles per day with an occasional weekend outing of 40-60 miles no problem.

You've mentioned "estimated mileage remaining" and x "miles remaining". Ignore the silly guess-o-meter. It's based upon recent driving history which may have nothing to do w/your future driving. TonyWilliams said it best about the GOM: http://www.mynissanleaf.com/viewtopic.php?t=11777#p271853.

You should instead use the % SoC value.

Good that you're monitoring miles/kWh. Keep in mind that on your 40 kWh Leaf, not all of that is user accessible. If Nissan's done what they have done on prior Leafs, there's some at the top and bottom that's not accessible.

Also, if the EVSE you're charging at says your car drew 7 kWh, not all of that makes it into the battery due to overhead and losses. Figure maybe 90% efficiency or so, so maybe 6.3 kWh or so got added to the battery.

Keeping your speed down will yield better efficiency and range. Unfortunately, I don' t see a 40 kWh version of Tony's range charts athttp://www.mynissanleaf.com/viewtopic.php?t=4295.

I cannot explain the entire discrepancy but here is some of it:

1) 7 kWh from the EVSE stop was pulled from the meter but somewhere between 0.85 - 0.9 made it to the battery; the remainder is charging losses.

2) The nominal capacity of your battery when new is 40 kWh but ~ 2 kWh are reserved as a safety buffer so at most you had 38 kWh usable. Of course the LEAF is famous for having battery degradation before the car is taken off the dealership lot so your usable is an unknown. You can use LeafSpy to learn the capacity but be aware that the app includes the reserve.

3) If the battery cooled down during the trip home (unlikely, but I suppose possible if the weather was consistent,) the battery capacity would drop. That is a bit of battery physics.

gnuthca said:

I charged up an additional 7 kWh at a local department store (L2 charge for about an hour or so)

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Question about this. Were you using something that told you that 7 kWh came out of the "wall"/station (e.g. ChargePoint app and/or its charging activity report) or were you guessing?

Common commercial power in the US is often only 208 volts, not 240. Most public L2 J1772 charging I've encountered tends to be 30 amps max. On the ChargePoint CT4000 series L2 EVSEs at my work which run at 208 volts, my Leaf tends to pull usually 5.8 to 6.0 kW, it can be has high at 6.1 or 6.2 kW.

Whenever I've used public charging, judging by Leaf Spy and/or ChargePoint app, I've only been at 1 or 2 places that actually had 240 volts (i.e. ChargePoint would show 6.6 kW power level and Leaf Spy in its 2 values one of the screens would should 6.0 kW going to the battery). The rest were 208 volts and some ChargePoint stations were causing my car to only draw as long as 5.7 or 5.8 kW, possibly due lower voltage at the station location.

What the station delivers could be lower (e.g. https://insideevs.com/under-threat-from-oems-ecotality-turns-down-the-output-on-chargers-to-avoid-failures/), the EVSE might not even be 30 amps or it could be a dual-handle CT4000 w/power sharing. In the last case, instead of running 2 40 amp feeds to the station (1 for each handle), they run a single one. So, if two cars are charging, each side is allocated only 15 amps, instead of the full 30 for each side.

You may also want to use Google Earth to see what the net elevation gain/loss is between the two points: https://priuschat.com/threads/google-earth-can-give-you-an-elevation-profile-of-a-route-between-2-points.100653/.

Here is a nice video with LeafSpy (LS)

https://youtu.be/u5DxpaQo7gI

The driver charged up to full and drove 120 miles at 60 mph until the car said empty.
Car meter: 100% SoC
LS: 38 kWh

Car meter: 0% SoC
LS: 3.8 kWh

His drive was at 3.6 miles per kWh, so he should have consumed 120.6/3.6 = 33.5 kWh
That matches up with starting at 38 kWh and stopping at 3.8 kWh: 38 - 3.8 = 34.2 kWh

Conclusions:
~ 2 kWh reserve at top, unknown reserve at bottom. My guess would be ~ 1 kWh reserved at the bottom so maximum usable ~ 37 kWh
Car meter is quite inaccurate at the bottom.
If you expect to squeeze the battery (not advised), then drive with LeafSpy
The miles/kWh is pretty accurate, so you can go by that with a little arithmetic if you start from a known quantity and do not let the meter reset until the next charging event.

^^^
I haven't watched the video but personally, I wouldn't want to assert anything based upon what Leaf Spy reports for kWh other than using them as estimates. It's just calculated from gids * a constant (default I think now is 77.5 Wh/gid).

Turbo3 has made a # of comments on the gids vs. watt-hours before like http://www.mynissanleaf.com/viewtopic.php?p=394038#p394038. http://www.mynissanleaf.com/viewtopic.php?f=44&t=14285&hilit=gids&start=1770 is another. You'll need to scroll down to the March 15, 2018 comment as linking to that exact post is busted.

I've posted http://www.mynissanleaf.com/viewtopic.php?p=510059#p510059 and the fact that Nissan has never released any documentation on anything Leaf Spy renders numerous times.

Thank you for posting the video. I hadn’t seen it before. What I thought was interesting was that the battery temp maintained or even increased during the run, in spite of 40 degree F temperatures outside. It tells me they have done a better job sealing the battery then the 2013 I drive. Even with my front grate taped shut, I would have lost battery temp over the 2-3 hours of driving.

So with 120 miles of range + 14 for the reserve + 4 for the heat used, puts the freeway range at about 140.

It’s making my hopes for 250 miles at 55 on the 60 kWh battery feel a bit unrealistic.

DougWantsALeaf said:

It’s making my hopes for 250 miles at 55 on the 60 kWh battery feel a bit unrealistic.

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Indeed

It’s making my hopes for 250 miles at 55 on the 60 kWh battery feel a bit unrealistic.

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Approaching it another way: the 40kwh Leaf seems to be good for 160 miles under those conditions. Make it 150 because of the extra weight of the 62kwh car. The arithmetic suggests ~225 real world miles for the ePlus in gentle highway driving.

LeftieBiker said:

It’s making my hopes for 250 miles at 55 on the 60 kWh battery feel a bit unrealistic.

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Approaching it another way: the 40kwh Leaf seems to be good for 160 miles under those conditions. Make it 150 because of the extra weight of the 62kwh car. The arithmetic suggests ~225 real world miles for the ePlus in gentle highway driving.

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He drove 120 miles using 95% of usable capacity, so 120/0.95 = 126 miles until stranded.

If the new LEAF has 1.5x the range then 126*1.5 = 189 miles until stranded.
I'll guess the actual usable capacities will compare at 59 and 37 kWh so 126 * (59/37) = 201 miles until stranded.

I'd be surprised if the 40kwh Leaf would only go that far at 55MPH - which is the speed proposed, not 60MPH.

Just observing on my own 40KWh Leaf, had 3 days of 120-125 mile days thus far. All 3 days were unseasonably cold & windy (low 20’s to high 30’s F), mostly expressway speeds in 65-70 mph range, and not sparing heat. Each ended at roughly 20% +/- and have yet to reach LBW. The dash is showing 3.8-3.9 miles/KWh averages (which is relatively poor economy compared to my ‘14 Leaf). Fairly confident I could squeeze out 200 miles under the right conditions.

LeftieBiker said:

I'd be surprised if the 40kwh Leaf would only go that far at 55MPH - which is the speed proposed, not 60MPH.

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Traveling at 55 mph instead of 60 mph saves about 10% energy per distance but keep in mind:

The video above was at way less than 60 mph average speed;
and the 60ish kWh LEAF will be heavier.

So maybe 210 miles. And of course this arithmetic of driving down to turtle is slightly unrealistic.