How Much Does the LEAF Lose In The Cold?

[RegGuheert]

Here is a general question....is there really this large of a drop off between 70 deg and say 40 deg if one does not use the heater? I am not yet a Leaf owner, but plan to buy a 2013 SV once they are available in Minneapolis. Typically, I don't have the heat on in my car until it's below 40.

From my perspective, the answer is "No." I do not see a significant drop in range until the LEAF gets below 30F. Still, I recommend that you get a heat pump in your 2013 LEAF to improve your comfort level and your ability to control the climate system. The 2011/2012 CC UI is so bad that the 2013 MUST be better!

 

[TonyWilliams]

Here is a general question....is there really this large of a drop off between 70 deg and say 40 deg if one does not use the heater? I am not yet a Leaf owner, but plan to buy a 2013 SV once they are available in Minneapolis. Typically, I don't have the heat on in my car until it's below 40.

From my perspective, the answer is "No." I do not see a significant drop in range until the LEAF gets below 30F. Still, I recommend that you get a heat pump in your 2013 LEAF to improve your comfort level and your ability to control the climate system. The 2011/2012 CC UI is so bad that the 2013 MUST be better!

So, at 31F, everything is great, and then BAM, 30F...

Really?

 

[kubel]

Here is a general question....is there really this large of a drop off between 70 deg and say 40 deg if one does not use the heater? I am not yet a Leaf owner, but plan to buy a 2013 SV once they are available in Minneapolis. Typically, I don't have the heat on in my car until it's below 40.

There would be a drop off of capacity but not a significant drop of energy economy. In other words, if you do 4 miles/kWh in the summer, you should be able to do close to 4 miles/kWh in the winter (assuming there are no other variables at play like using heater, driving with snow tires, pushing through snow, etc...). But you will not be able to 'fill up' with ~21kWh in the winter like you can in the summer because a cold battery is not capable of storing as much energy as a warm battery.

 

[RegGuheert]

So, at 31F, everything is great, and then BAM, 30F...

Really?

No. I didn't say there was a step change. What I said was that I don't notice a significant drop until temperatures get below 30F.

Basically, I feel the drop in range between 70F and 30F is very small, around 5% or so. But the slope of range versus temperature below 30F is steeper. I think this could be due to two main factors:

1) Above 30F there is little need for heat, since we wear coats at those temperatures, but below 30F, we tend to want heat, even with our coats on.
2) I notice the mi/kWh number tends to drop pretty quickly as temperatures go below 30F. I get the impression this is due to viscosity changes in gear and bearing lube as well as in tire stiffness. I don't see a big shift in this number at higher temperatures. Also I notice that this number will recover in the cold after driving a few miles, but it never gets back to what I see in warmer temperatures.

Edit: For reference, here is a plot from Alternative Energy Magazine showing the effect of temperature on C/2 discharge capacity of an NCM (NMC?) Li-ion cell:
Note that there is one slope between 20C and -10C and a steeper slope below -10C. This curve indicates about 7% drop in capacity in this cell between 20C and 0C, but this is a different cell and it is discharged at a higher rate than I typically drive (C/8?).

 

[scottf200]

Hopefully all readers understand that there is a logger that is used to track real time data. Hence the 5,400 trips worth. On the Volt there is two "OBDII" ports and their logger uses both as the 2nd contains additional information. This page mentions a LEAF harness but that may just be the 'extension' cable. On the Volt's it is a Y cable..

http://www.fleetcarma.com/Content/docs/FleetCarma_C5_SpecSheet_1page.pdf" onclick="window.open(this.href);return false;

 

[RegGuheert]

Hopefully all readers understand that there is a logger that is used to track real time data. Hence the 5,400 trips worth.

That still doesn't answer what they are plotting. Even if it uses the mi/kWh as Tony said, you are still missing a factor. What do they use for the capacity of the battery versus temperature?

So perhaps the data in the plot comes from a fleet vehicle rather than a personal vehicle?

 

[evnow]

Basically, I feel the drop in range between 70F and 30F is very small, around 5% or so. But the slope of range versus temperature below 30F is steeper.

Being in Seattle I've a lot of data between 70 F & 40 F. Not much below that.

I see significant range reduction, even without heater between 70 & 40 (as do everyone who posts at the Seattle Leaf Owners Facebook group).

I'll post some numbers tomorrow.

 

[scottf200]

Hopefully all readers understand that there is a logger that is used to track real time data. Hence the 5,400 trips worth.

So perhaps the data in the plot comes from a fleet vehicle rather than a personal vehicle?

You imply a single vehicle. The quote in the opening post indicates:

Fleetcarma has compiled data from more than 5,400 trips of Leaf owners throughout North America, to see what effect temperature has on range.

 

[evnow]

You imply a single vehicle. The quote in the opening post indicates:

Fleetcarma has compiled data from more than 5,400 trips of Leaf owners throughout North America, to see what effect temperature has on range.

That's what makes the data fairly useless, except to establish some correlation.

 

[edatoakrun]

It is very difficult to differentiate the loss of range due to lower kWh storage due to lower battery temperature, from the loss of range due to lower m/kWh due to colder ambient driving temperatures. The rough results I posted over a year ago on a similar thread seem to have held up in my subsequent observations, and I can't really say what what happens in more extreme temperatures, since I personally never wanted to experience the level of discomfort entailed in avoiding heater and AC use at below ~freezing or above ~100 F temps, over a multi-hour trip.

On 11/8(11) I attempted to replicate the route and conditions of an earlier trip, which I had kept careful notes of, to try to see what sort of range reduction is caused by reduced m/kWh due to lower temperatures, and what proportion of this reduction is due to reduced battery capacity. I did this on a dry day with windows up, without using the heater or windshield wipers. I believe that I got about 5% reduction in battery capacity, and a slightly larger decrease in driving efficiency (m/kWh) resulting in a total range reduction of over 10%...

So this approximately 40 degree decrease in temp when charging, and 50 degree reduction when driving, resulted in about 10% recorded range reduction...

http://www.mynissanleaf.com/viewtopic.php?f=31&t=6701&start=60" onclick="window.open(this.href);return false;

 

[RegGuheert]

It is very difficult to differentiate the loss of range due to lower kWh storage due to lower battery temperature, from the loss of range due to lower m/kWh due to colder ambient driving temperatures.

I do think your range test is a useful one since you used nearly the full battery capacity, but I'm not sure it's possible to differentiate between battery effects and efficiency changes when the measurement system is likely quite dependent upon temperature. That's why Tony has always stressed the importance of 100% to shutdown range tests.

 

[dgpcolorado]

Here is a general question....is there really this large of a drop off between 70 deg and say 40 deg if one does not use the heater? I am not yet a Leaf owner, but plan to buy a 2013 SV once they are available in Minneapolis. Typically, I don't have the heat on in my car until it's below 40.

In my experience there is not that much of a drop in mileage between 70ºF and 40ºF on dry roads, although there is some. I do see a seasonal drop in mileage, as you can see from this chart:


However, you can get somewhat colder in MN than I get here and I get more sun (a sun-baked car in 20ºF outside temperatures is quite pleasant). I also never drive freeways and the maximum speed here is 60 mph, which I never exceed. A lot depends on your individual circumstances:

Do you plan to garage your LEAF? Does your garage stay above freezing? Mine does and that means I take only a small hit to battery capacity in winter. On the other hand, if you park outside overnight in 0ºF weather you will take a large hit to battery capacity and the charging speed will be slowed considerably, as Tony Williams said. Whether that matters depends on how far you will be driving. Twenty miles? No problem. Fifty miles? That could be difficult.

Will you be driving it in snowstorms? Will you put snow tires on it? If you don't make long trips, say more than 40 miles, the LEAF makes a fine snow car.

I don't usually use the heater because I dress for winter and the steering wheel and seat heaters are adequate. But the ability to preheat in the morning while plugged-in is a really big deal in the LEAF. Getting into a prewarmed car is means I can go without heat for at least a half hour even in very cold (below 0ºF) weather. I do have to cycle the defrost to keep the windshield clear; I do this without using the heater. If you don't use the heater now in 40ºF weather, my guess is that you won't need it much in a LEAF at much colder temperatures, especially if you preheat it.

Do you plan to drive at freeway speeds in winter temperatures? If so, and you are pushing the range, can you slow down or take an alternate route?

So, a lot depends on your personal circumstances. If you want to drive fifty plus miles in a snowstorm, better to take the ICE car.


Full disclosure: I am something of an easy-does-it driver, borderline hypermiler. If you "drive like you stole it" your mileage will be much worse than mine. I also have the advantage of high altitude and the disadvantage of steep hills (1000 to 2300 feet) everywhere I go.

 

[Reddy]

Sorry, if they are using my car in the average, I'm really skewing it low. :lol: I'm getting in the low 2 mi/kwh right now. That's what happens when you leave the heater on 90 F and drive less than 10 mi RT in stop and go traffic. Who cares what my range is? It's easily 5 times what I need on any normal day. I easily get 5+ mi/kwh in the summer and can do long trips when I want. What really matters is that I now have a toasty warm car that cost pennies to drive instead of my old gas guzzler that never warmed up until I got to my destination and cost nearly ten times as much in fuel.

Reddy

 

[scottf200]

Related story on the Model S which I read with interest as I live in cold Chicagoland and am interested in the Model X
Stalled Out on Tesla’s Electric Highway
http://www.nytimes.com/2013/02/10/automobiles/stalled-on-the-ev-highway.html?pagewanted=all&_r=2&" onclick="window.open(this.href);return false;

Making matters worse, cold weather inflicts about a 10 percent range penalty

[update]
A Response to: Stalled on the E.V. Highway
http://electricroadtrips.com/a-response-to-stalled-on-the-e-v-highway/" onclick="window.open(this.href);return false;
[/update]

 

[derkraut]

Nissan Leaf Range: How Much Does It Lose In The Cold?
BY ANTONY INGRAM 1,912 views Feb 1, 2013

http://www.greencarreports.com/news/1082048_nissan-leaf-range-how-much-does-it-lose-in-the-cold" onclick="window.open(this.href);return false;

Fleetcarma has compiled data from more than 5,400 trips of Leaf owners throughout North America, to see what effect temperature has on range.

Yes, Volt obviously loose range in winter as well but certainly a little differently because of TMS. Climate settings are biggest culprit for both obviously.

[update]
Hopefully all readers understand that there is a logger that is used to track real time data. Hence the 5,400 trips worth. On the Volt there is two "OBDII" ports and their logger uses both as the 2nd contains additional information. This page mentions a LEAF harness but that may just be the 'extension' cable. On the Volt's it is a Y cable..
http://www.fleetcarma.com/Content/docs/FleetCarma_C5_SpecSheet_1page.pdf" onclick="window.open(this.href);return false;
[/update]

Well....I'm a bit confused: Today (2/8/2013) I drove 61 miles on an 80% charge, almost all freeways @ a steady 60mph. It was raining on & off, rather strong (15-25mph) wind, wipers & headlights almost always on, no climate control, OAT 55 deg. At the end of my trip, I was on LBW, 6mi on GOM, one battery bar. My car is 10 months old, mileage is 11,465. I guess my battery is performing better than most? BTW, I have never gone to VLBW or turtle, have charged to 100% probably a total of 15 times, otherwise, always to 80% at night with the car timer. I've never seen less than 5 or more than 6 battery temp bars. I don't "baby" my cars; but I do take good care of them. IMHO, it makes a difference.

 

[TonyWilliams]

Well....I'm a bit confused: Today (2/8/2013) I drove 61 miles on an 80% charge, almost all freeways @ a steady 60mph. It was raining on & off, rather strong (15-25mph) wind, wipers & headlights almost always on, no climate control, OAT 55 deg. At the end of my trip, I was on LBW, 6mi on GOM, one battery bar. My car is 10 months old, mileage is 11,465. I guess my battery is performing better than most? BTW, I have never gone to VLBW or turtle, have charged to 100% probably a total of 15 times, otherwise, always to 80% at night with the car timer. I've never seen less than 5 or more than 6 battery temp bars. I don't "baby" my cars; but I do take good care of them. IMHO, it makes a difference.

You didn't give us the economy from the dash (miles/kWh), so we really have to do some serious guessing.

Driving through rain at 60mph with no heater? Could be as good as 4.3 miles/kWh, which with a new, warm battery is good for 4.3 * 21 = 90miles. You also didn't tell us how many miles past LBW (and the GOM doesn't help, nor does the fuel bars when a battery warning is displayed).

I'll arbitrarily say you had 15% usable battery left. You should have traveled 72 miles at 80% charge at 4.3, therefore 15% remaining battery is 11 miles, or 72 - 11 = 61 miles range.

Tons of guessing, but everything looks great for your battery.

 

[derkraut]

My economy from the dash showed 4.3; I drove 6+ miles after LBW; so I guess you're right on the money, Tony. Last night, on the timer I charged to 80%. The Blink shows a cost of $2.16 for the 61 miles driven yesterday.
Since I am an old, stingy codger, I am also a happy codger. :mrgreen:

 

[TonyWilliams]

My economy from the dash showed 4.3; I drove 6+ miles after LBW; so I guess you're right on the money, Tony.

Almost like I know what I'm doing !!! Although, driving 6 miles past LBW does throw out some of my original data.

I hate to break it to you, but your battery is not new anymore.

 

[Reddy]

Went out of town again last weekend for dinner and a show. Same trip as described here without the in-town circling to get to turtle:
http://www.mynissanleaf.com/viewtopic.php?f=31&t=7634&p=243033&hilit=cold#p243033
Last time we took the L1 and charged about 1.5 hr at dinner. This time, forgot the cord (how's that for getting used to town driving and always leaving the L1 mounted in the garage). Oh well, I knew I could still make it, just with a bit less heat. Drove 62 mi RT, pre-heated, 100% charge (well a bit less 11.5 bars?). Garage temps around 40 F during charging. Very little energy consumed for heating on the outbound trip due to pre-heat. Arrived with 6 bars. About 400 ft net elevation gain with lots of hills. Drove mixed speeds 35-60mph. Return trip was about 25 F. Used heat sparingly until about about 5 mi from freeway exit to make sure I could make it, then full on for the remaining 10 miles. Arrived about 3 miles after LBW but before VLBW. This is my 4th time on this route, all near freezing temps. Once you push it to VLBW or turtle, it is much easier to use the car right down to line (adjusting speed or heat as needed) and still arrive home with a couple of miles buffer. Still, I don't recommend such trips without taking the L1, just in case. Hopefully, I'll remember next time.

Reddy

 

[scottf200]

<snip>
Very little energy consumed for heating on the outbound trip due to pre-heat. [read as didn't use heat or barely any]
<snip>
Drove mixed speeds 35-60mph. [max 60?!?]
<snip>Used heat sparingly until about about 5 mi from freeway exit to make sure I could make it

I think some of us still have a valid point that this is not the way the masses (general public) want to live with their cars. Low to little heat and baby car/pedal.

I'm not putting down the LEAF here because all our *EVs have this issue. My cold weather range is quite a bit less then my spring/summer/fall range.

Post like the above just preach to the choir. Try telling the same story to Joe and Jane doe and tell them that is how they need to drive their new car. I'm just trying to be straight / honest here. I tell potential Volt owners what they can expect in the winter using the car just as they do their ICE. Did that in the grocery store parking lot on Sat when I got out and was asked about the car.