How Much Does the LEAF Lose In The Cold?

[Reddy]

I'm just trying to be straight / honest here.

I won't try to do the full quote, since I'll probably mangle it anyway. A couple of points:
1) Outbound: Heat was used (ON) but because of pre-heating, very little KWH were used.
2) Heat was ON during the return. Hmmm, "sparingly", I don't know maybe 25% of the freeway? Yes, this was definitely not "normal" and I admit as much. See 5) below.
3) We were not cold during either out bound or return. We dress for winter here, just like any smart person would. Since it was a show, we were dressed for a night out. Sorry, we wear the T-shirts and flip flops in the summer.
4) Sorry, I drive the legal speed "limit" and not above, although not stomping to get there. I try not to advocate law breaking behavior, no matter how small it may seem. Since I don't live on a freeway on-ramp, I drove on a range of roads, one was even 25 mph while leaving the neighborhood (oops, forgot to mention that). Is that what everyone else does? Heck no, I was definitely passed on some of the roads, although I also passed people. I did get to the same red light cycles that everyone passing me did, only with less stress and energy use. On the freeway many people were driving 60-70. We tend to drive slower around here.
5) Preparation: I'll admit my mistake for forgetting the L1 trickle charger. Dumb, and I accept the consequences of my action. For the last trip, we used it and that provided the extra buffer so that I had the heat blasting at 90 F most of the way home (until it was too hot). As for other preparations, no, I didn't take the emergency/earthquake kit, emergency tools, battery jumpers, blankets, or extra food (sandwiches, hot chocolate, etc.) that my family always had on road trips. I suppose I felt like this trip didn't warrant it. My bad. Fortunately, there were no other accidents or weather that could have made it more disastrous. I'll get that emergency kit put together and in the trunk as soon as possible.
6)Preaching to the choir? Guilty, since that's mostly who reads this forum. I guess my main point is that I am learning how much to drive the car to its fullest potential and you can too. Everyone's limits will be different. I certainly don't recommend driving 60+ mi at 25 F on a daily basis (especially out here in Sticksville where I was either 40 or 50 mi in either direction to the nearest public L2). However, 60+ mi in warmer temperatures is very easy, even with the L1 in the trunk.
7)We chose to drive the Leaf over the 20 mpg 1992 ICE that sits in the garage most of the time because of the preferable quiet smooth ride and music system. If I could owned a Volt, then yes, these extra precautions may not be necessary. Actually, my normal driving (<10 mi RT commute) is well-suited to the Volt. Had it come out early than the Leaf, I might have considered it. As it is, I'm stuck with my ICE or a rental for 1-2 trips/yr to Seattle (well, at least until we get a DCQC at the Yakima Nissan dealership. I'm not holding my breath on that one).

Hope these clarifications help.

Reddy

 

[evnow]

I found an old chart I had made showing m/kWh vs temperature.

All these trips were made by me, using the same route (my commute). So, it is really comparing apples to apples.

 

[RegGuheert]

I found an old chart I had made showing m/kWh vs temperature.

All these trips were made by me, using the same route (my commute). So, it is really comparing apples to apples.

Thanks!

So your mi/kWh on your dash drops from 5.1 to 4.1 as you go from 70F to 40F, or nearly 20%? That comes fairly close to the chart in the thread starter post, which apparently is also based purely on mi/kWh from the dash. And I will assume your battery capacity drops about 5% as well over that temperature range. That means your range would drop about 25% with a 30F drop in temperature. But that is over three times the range reduction with temperature that Tony projects in his range chart. That is a BIG disparity!

Perhaps where you live it gets rainier or windier as it gets colder? Or perhaps the mi/kWh meter in the LEAF has a strong temperature coefficient. I suspect the latter.

My *range* experience is nowhere near that level of drop. At 40F I can make a 75-mile trip crossing a mountain twice and return home just below LBW while I would be just above LBW for the same trip at 70F.

 

[TonyWilliams]

I found an old chart I had made showing m/kWh vs temperature.

All these trips were made by me, using the same route (my commute). So, it is really comparing apples to apples.

Thanks!

So your mi/kWh on your dash drops from 5.1 to 4.1 as you go from 70F to 40F? And I will assume your battery capacity drops about 5% as well over that temperature range. That means your range would drop about 25% with a 30F drop in temperature. That comes fairly close to the chart in the thread starter post, which apparently is also based purely on mi/kWh from the dash. But it is over three times the range reduction with temperature that Tony projects in his range chart. That is a BIG disparity!

You are not reading the Range Chart properly if you are making comparisons like this.


The lowered economy in cold weather (and specifically NOT battery capacity reduction in cold) can easily be attributed to many things. Most notably HEATER use will be the prima facie cause from the LEAF's power hungry resistance heater. In addition, winter time roadway contanimation (snow, standing water, ice, slush) will obviously reduce economy on any road vehicle. Finally, the considerably more dense cold air of winter will increase aerodynamic drag at 1% per thousand feet change in density altitude, thus decreasing economy at the same speed.


Our testing (last winter) to measure the cold weather effects of capacity loss was done without the heater to determine our formula for the Range Chart; 1% loss per 4F degrees of battery temperature below 70F. This has nothing to do with economy losses.


Together, both economy losses and capacity losses will equal some dramatic changes in winter time range autonomy, particularly in an electric car with neither the means to regulate battery temperature nor an efficient heater. It's awesome that your particular car appears to be so efficient from the norm, however I suspect a critical review will prove otherwise.

 

[RegGuheert]

You are not reading the Range Chart properly if you are making comparisons like this.

The lowered economy in cold weather (and specifically NOT battery capacity reduction in cold) can easily be attributed to many things. Most notably HEATER use will be the prima facie cause from the LEAF's power hungry resistance heater. In addition, winter time roadway contanimation (snow, standing water, ice, slush) will obviously reduce economy on any road vehicle. Finally, the considerably more dense cold air of winter will increase aerodynamic drag at 1% per thousand feet change in density altitude, thus decreasing economy at the same speed.


Our testing (last winter) to measure the cold weather effects of capacity loss was done without the heater to determine our formula for the Range Chart; 1% loss per 4F degrees of battery temperature below 70F. This has nothing to do with economy losses.

evnow claimed earlier in this thread that his results were created without the use of the heater:

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.

Together, both economy losses and capacity losses will equal some dramatic changes in winter time range autonomy, particularly in an electric car with neither the means to regulate battery temperature nor an efficient heater. It's awesome that your particular car appears to be so efficient from the norm, however I suspect a critical review will prove otherwise.

I'm sorry, but the X-axis on the graph in the OP and the graph from evnow is temperature. While the OP chart certainly includes heater use, evnow claims he did not use the heater. If there are other variables included in these charts, they should be disclosed. And still the accuracy of the instrumentation is a question. There was one post showing wall energy with some agreement.

Frankly, my BEST result on the trip I described was this January on a 50F sunny day when I used only four bars to get to the destination 37 miles away (five after restarting). I returned home with two bars remaining. This trip has limited opportunity for hypermiling since it is mostly highway driving. If I can dig up a couple of Carwings results from this trip, I will post them here.

 

[TonyWilliams]

The lowered economy in cold weather (and specifically NOT battery capacity reduction in cold) can easily be attributed to many things. Most notably HEATER use will be the prima facie cause from the LEAF's power hungry resistance heater. In addition, winter time roadway contanimation (snow, standing water, ice, slush) will obviously reduce economy on any road vehicle. Finally, the considerably more dense cold air....

I'm sorry, but the X-axis on the graph in the OP and the graph from evnow is temperature. While the OP chart certainly includes heater use, evnow claims he did not use the heater. If there are other variables included in these charts, they should be disclosed. And still the accuracy of the instrumentation is a question. There was one post showing wall energy with some agreement.

All the loss of economy issues that I posted still apply; the heater is just the most likely candidate whenever these economy-in-winter discussions come up. Yes, we already know that the LEAF instrumentation is error prone, and temperature variable. We also have charts ad nauseum showing what similar chemistry batteries to the LEAF do in cold and hot.

The variables on my chart have been defined for about 18 months.

Frankly, my BEST result on the trip I described was this January on a 50F sunny day when I used only four bars to get to the destination 37 miles away (five after restarting). I returned home with two bars remaining. This trip has limited opportunity for hypermiling since it is mostly highway driving. If I can dig up a couple of Carwings results from this trip, I will post them here.

Without the economy, this doesn't tell us much. I'm personally not interested in CarWings data, but perhaps others are.

Battery temperature is critical for accurate data. When we tested, cars were left "cold soaked" at ambient temperature for many hours to ensure that we knew where the battery temperature started.

My point is simple; there isn't much that you're questioning that hasn't been tested and documented many times previously. I'm sure there are plenty here that would be happy to help you define the parameters for a cold weather tests, as we have done in the past.

 

[RegGuheert]

All the loss of economy issues that I posted still apply; the heater is just the most likely candidate whenever these economy-in-winter discussions come up. Yes, we already know that the LEAF instrumentation is error prone, and temperature variable.

Agreed. That's my point: You cannot accept the LEAF's dash efficiency numbers over temperature as being indicative of the efficiency of the LEAF over temperature.

We also have charts ad nauseum showing what similar chemistry batteries to the LEAF do in cold and hot.

Yes, and I posted one in this thread which shows two breaks in capacity as a function of temperature: one at around 10F and the other at around 60F. Your chart only has one break point, but it suits me since it almost never gets below 10F here.

The variables on my chart have been defined for about 18 months.

Your chart works fine for me.

Without the economy, this doesn't tell us much.

Agreed. Unfortunately, I don't think we get credible efficiency numbers spanning a range of temperatures from the LEAF's dashboard. We may be able to use the LEAF's dash efficiency numbers to compare efficiencies of different trips at some given temperature, but that's about it.

I'm personally not interested in CarWings data, but perhaps others are.

So be it, but that's where the LEAF's reported efficiency numbers are stored. Unfortunately, I was unable to get Nissan to fix the Carwings efficiency reporting bug in our LEAF until the end of September, so all data before that time was useless. It's been fine since then.

So here is what I've seen:

All last summer, this trip to our children's orthodontist was achieved with dash efficiencies of 5.1 to 5.4 mi/kWh, yet we always arrived with only seven battery charge bars showing. One such trip was on September 3 and Weather Underground reported a high temperature of 80F.

January 8 was the most recent excursion to the orthodontist and for the first time ever I arrived at the orthodontist with eight battery charge bars showing. I did more hypermiling on that trip than I have ever done previously, yet Carwings reports that the driving efficiency was 4.6 mi/kWh in both directions of the trip. Weather Underground reports the high temperature that day to be 53F.

The simply fact is that on January 8 I drove more conservatively than I previously had and I arrived at the destination with more remaining charge bars than I ever have before, yet the LEAF thinks that the efficiency of the trip was 10% lower. If that were true, and if the battery really held less charge in January due to being 30F colder, then how can these same gauges report a higher SOC at the destination?

My conclusion is that, for this particular trip on January 8, the efficiency of the drive was actually HIGHER than what was achieved on September 3, but the LEAF reported it to be lower. An alternate conclusion would be that the LEAF gave me access to more than 10% additional battery capacity in January than it did in September. I suppose it's possible that operation of the BMS or better cell balancing could make something like that happen.

Regardless of the reason for the inconsistent data, the bottom line is that the mi/kWh data from the LEAF is a very poor proxy for the range of the car as a function of temperature.

It seems that Tony agrees:

I challenged these guys a bit on their data in a Facebook exchange. They just determined the range based on how many miles per kWh.

That's it.

Oy Vey.

 

[evnow]

evnow claimed earlier in this thread that his results were created without the use of the heater:

I should clarify - the graph I posted above is (as I said) an old one - I'm not sure exactly what went into that (i.e. whether it included the heater days).

But my experience is a significant drop in m/kWh (and range I've experienced) even without the heater. I'll post something more definitive from my data points when I get time.

 

[elmobob]

The leaf looses a big chunk of range specially when below 32F because regen is almost completely cut off, I don't think the battery being cold has so much to do with it. Even when it shows 4 regen bubbles available as soon as you hit 30mph they go away but one, and that one regen bubble comes on slowly after the car has almost slowed down to half the speed. It might be because nissan is protecting the battery from getting too many KWs feed back when the battery is cold. Here is what my dash looks like on a typical cold morning in NY. Even thou the GOM says 73 miles with an 80% charge i would not push it past 50.

 

[Reddy]

Three battery bars, yum. Are you parked outside overnight?

 

[TonyWilliams]

The leaf looses a big chunk of range specially when below 32F because regen is almost completely cut off, I don't think the battery being cold has so much to do with it.... Even thou the GOM says 73 miles with an 80% charge i would not push it past 50.

Anytime somebody quotes the GOM for anything meaningful in actual bona fide range autonomy claims tends to throw any credibility out the window. It frankly does not matter what the GOM says.

Secondly, you could not be more wrong about cold effects on the LEAF battery (or virtually any battery). If the LEAF is driven down a level highway at a steady speed, there won't be any regen whether the battery is hot or cold.

Quite simply, a new, non degraded, LEAF with a 70F degree or warmer battery on a sea level elevation, level, dry, no wind roadway will bang out 84 miles of range autonomy at 4 miles per kWh. Please see our testing from Phoenix. Again, just to be clear, there is no regen while cruising at a steady speed in the above parameters.

That same LEAF, driven in the exact same conditions except a -10F / -20C degree battery will travel 20% less range autonomy.

 

[elmobob]

The leaf looses a big chunk of range specially when below 32F because regen is almost completely cut off, I don't think the battery being cold has so much to do with it.... Even thou the GOM says 73 miles with an 80% charge i would not push it past 50.

Anytime somebody quotes the GOM for anything meaningful in actual bona fide range autonomy claims tends to throw any credibility out the window. It frankly does not matter what the GOM says.

Secondly, you could not be more wrong about cold effects on the LEAF battery (or virtually any battery). If the LEAF is driven down a level highway at a steady speed, there won't be any regen whether the battery is hot or cold.

Quite simply, a new, non degraded, LEAF with a 70F degree or warmer battery on a sea level elevation, level, dry, no wind roadway will bang out 84 miles of range autonomy at 4 miles per kWh. Please see our testing from Phoenix. Again, just to be clear, there is no regen while cruising at a steady speed in the above parameters.

That same LEAF, driven in the exact same conditions except a -10F / -20C degree battery will travel 20% less range autonomy.

Is not that I take the GOM seriously, I'm just saying it's been my experience that an 80% charge will probably leave me stranded if I push it more than 50 miles in this weather. Also I did not say the cold does not affect the range I just said not as much, I happen to do allot of stop n go driving in NYC and I can certainly say that not having the 5 regen bubbles available does not help the range at all and it's not the heater since I don't use it. Again it's my experience, I drive the leaf like a NYC yellow cab in a rush :lol: not into trying to squeeze the most range out of the battery, since my commute is 14 miles each way I don't usually feel the need to.

 

[RegGuheert]

The leaf looses a big chunk of range specially when below 32F because regen is almost completely cut off, I don't think the battery being cold has so much to do with it. Even when it shows 4 regen bubbles available as soon as you hit 30mph they go away but one, and that one regen bubble comes on slowly after the car has almost slowed down to half the speed. It might be because nissan is protecting the battery from getting too many KWs feed back when the battery is cold.

That problem has been reported before in this thread. I have been completely unable to duplicate this problem myself, which I thought was because the local mountain is not high enough. But perhaps it is because I have never seen three battery temperature bars. You might want to have a look and comment there. (The thread is not very old.)

 

[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.

I'm going to answer this again, but this time, I will use Nissan's data for the 2013 model found in this chart:

This chart shows the range of the LEAF WITH CLIMATE CONTROL ON. What is interesting is that the peak range does NOT occur at 70F in the 2013 as we have been told for the 2012, but rather it occurs below about 60F. Eyeballing the chart provided tells me that the 2013 LEAF should have very slightly less range at 40F than at 70F with climate control on according to Nissan. (The pink arrow is right around 40F.)

 

[elmobob]

Three battery bars, yum. Are you parked outside overnight?

Yup, we have a single car garage and my significant other parks her ice there since she always gets home first, my evse cord is long enough to reach the driveway where I park and charge overnight. On the upside from what I read on the forums it might do good for the life of the battery.

 

[DaveinOlyWA]

I just love this forum! Whatever range numbers folks publish, they get invariably get accused of being either too high or too low; as often is the case, the truth lies somewhere in between. FWIW, based on my experience, this particular set of numbers is definitely on the low side (and that's with my 18 month old battery pack).

YMMV so ya, its one set of data points. whether its 5 trips or 5400 trips, its still one set, one location, one everything.

have to wonder about a data set where even in the best temperature range, you cant get 70 miles?? is this an AZ car?

 

[DaveinOlyWA]

these range estimates are relative. if this chart is an aggregate then we need to see a range of figures. a single line is not illustrative enough without knowing highs/lows/mediums.

now each drives in a different way in a different location, etc. but for me?

I get about 75 miles in Winter and that is minimal or no heat. generally just enough defrost to clear the windows which can be a little on dry days and a lot on wet days. On wet days due to additional road resistance, my range in more likely 70-73 miles depending on severity of the precip

In Summer, its near 90 with A/C. so there ya go.

 

[GetOffYourGas]

Three battery bars, yum. Are you parked outside overnight?

Yup, we have a single car garage and my significant other parks her ice there since she always gets home first, my evse cord is long enough to reach the driveway where I park and charge overnight. On the upside from what I read on the forums it might do good for the life of the battery.

You're lucky to have enough room for a garage in Yonkers (my sister used to live off Nepperhan Ave). From what I've read, the battery life benefit is more in the summer than the winter due to heat. In the winter, parking in the garage will likely have little to no affect on battery life, but potentially a significant affect on range (a warmer battery holds more energy).

I know you said you have plenty of range for your needs, so it will likely never be an issue for you. Just something to keep in mind if your situation changes (e.g. you change jobs to a longer commute).

 

[planet4ever]

What a beautiful sunny day we had here today! Temps in the low 70's, and hardly a breeze. My LEAF and I traveled 33 miles, about a third of it freeway, and got 4.5 m/kWh. I know, that's not particularly remarkable, except that:

• I'm not what you would call a timid driver, having averaged only 4.0 m/kWh over the life of the car.
• Unlike the apparent majority of LEAF drivers, I usually get my worst mileage driving in town.
• For the past three months my daily averages have been between 2.9 and 3.6 m/kWh.

There was nothing unusual about the way I drove or the route I took today. The difference was that until now the high temperatures here have been in the 40's or 50's. My wife and I do pamper our ancient bodies (average age 79), and that means we've been using the heater. No, our 2011 model has no heated seats, and of course no heat pump. We can't claim that it's really cold in the Bay Area, but even here the temperature sure can make a huge difference.

Ray

 

[DaveinOlyWA]

i am with you Ray'. I have a day that used to be weekly but is now about once a month due to work conflicts where I have several errands i run so its pretty much a set route with 80% of it being in town. During the Summer I average 5.8 to 6.2 miles/K. Winter about 4-4.3. The other day I posted pix on FB that I was at 5.3 miles per K. no difference in route, slight differences in traffic (as always) but only real change? the near 60º weather with full Sun.

this route I have driven in the LEAF probably 60-75 times so its pretty much not too variable. the route is chosen for its lack of traffic controls so has minimal lights and yes I have lived in 3 different places during the time I have had my LEAF but the locations were all very close to each other (current house less than a mile from other house (we did move but only lasted 15 months in interim house that was in between)