My Leaf Stats : Range vs Temperature

Winter does seem to be a whole other kettle of fish. this morning I charged to 80% when it was still cold and then later this afternoon I went out to drive and noticed it showed 11 bars instead of the usual 10... and the air temperature had warmed, presumably causing another bar to "grow". This is going to be an interesting couple of months!

After 3 Blink QC's, one at 100% (86% SOC gauge/12 bars), two at 90% (SOC at 76% & 79%/9 bars), I L2 charged (Blink) tonight to 80% from 5 bars to 10 in 96 mins.and my gauge hit 81.4%! It's usually 76.8%. I'm wondering if the QCs are balancing my pack or is it something else? It was around 70 degrees in the garage.

I noticed a similar situation yesterday. I didn't grow any bars per se, but my normal 80 percent charge over night resulted in far less regeneration (only two circles) than I usually have when I left in the afternoon. Also, my first (tenth) bar lasted for over 11 miles, which is atypical.

GaslessInSeattle said:

Winter does seem to be a whole other kettle of fish. this morning I charged to 80% when it was still cold and then later this afternoon I went out to drive and noticed it showed 11 bars instead of the usual 10... and the air temperature had warmed, presumably causing another bar to "grow". This is going to be an interesting couple of months!

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I've driven a week or so in the low 40's. Tried a couple days with climate control and another few without.

For reference, in the high 60's or above, I get 4.2-4.3m/kwh every day on my commute. In the low 40's, I get 3.5 with cc off. CC on might drop that 1-2 points. I don't remeber ever getting 4.4 on my full route (not since getting these tires anyway , and I only get below 4.2 if I drive dramatically different for some reason (late for work & take the interstate instead of my normal route for example).

When the cold front first hit, the efficiency drop was sudden and extreme - I was instantly getting low 3.x's. When I finally started working out how to run the heater as minimally impactful as possible (set it in the 70-72 range, pre-heat in the morning, keep the defrost off, keep it in eco) I think I maxed out at around 3.5.

I tried a couple days with CC off (as much as possible - ran defrost for 10-15 seconds at a time 3-4 times to keep the windows clear)). Still around 3.5. And I know the spurts of defrost were not the issue, it was reduced right from the start (surely I'm not the only one that knows what the efficiency should be at certain points on my route, right? )

Heat can be a huge drain, but it doesn't have to be. The cold is still a HUGE impact to the range, regardless of CC.

defiancecp said:

The cold is still a HUGE impact to the range, regardless of CC.

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So I observe... Here in Souther California, we have different climate zones. Last Friday night, I went out to the Valley area of Los Angeles, and my car sat in a lot for several hours--8PM to Midnight--that night at temps in the low 40's--as compared to mid 60's more typical where I live in WLA. There was a significant reduction of available energy--it caught me unaware--even so I had plenty of juice to get home, but I've been warned.

This video shows how Volvo may use ethanol to heat both cabin and battery to extend their BEV's range in winter.

http://www.youtube.com/watch?v=FjLqcJkGkRo&feature=player_embedded" onclick="window.open(this.href);return false;

Sounds complicated and expensive to me, but probably cheaper than loading up the car with more batteries, for BEVs in extremely cold climates.

I’m planning a no recharge (?) drive of about 88 miles and 6,000 ft. ascent/descent today, to see what the 35 degree F temperatures, during charging this AM, did to my range.

edit 7:03 pm.

Missed it by that much...

evnow said:

Then, we are back to the question of - why does m/kwh go down even when not using CC.

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You've come a long ways from accusing me of making it up when I told you that winter was going to take a bite out of the Leaf's range. At least you're now asking why.

Even with CC off you have top line and adjustment issues. A cold battery isn't going to produce the same amount of energy as a warm one. That's the top line problem. The adjustments are that you have increased aero losses due to colder air, increased rolling resistance losses due to colder tires, and increased drive train losses due to colder parts. Throw in reduced regen due to increased losses, plus some wind for good measure, and it's not too hard to end up with a 25% hit to the range. Throw in heating and that can go to 30% and even up to 40%.

The good news is that 40% is probably the worst case scenario, but time will tell. The other good news is that, unlike heat, which will kill the battery, cold just reduces it's performance.

The same situation persisted today, with 12.1 miles on the first bar...

TomT said:

I noticed a similar situation yesterday. I didn't grow any bars per se, but my normal 80 percent charge over night resulted in far less regeneration (only two circles) than I usually have when I left in the afternoon. Also, my first (tenth) bar lasted for over 11 miles, which is atypical.

GaslessInSeattle said:

Winter does seem to be a whole other kettle of fish. this morning I charged to 80% when it was still cold and then later this afternoon I went out to drive and noticed it showed 11 bars instead of the usual 10... and the air temperature had warmed, presumably causing another bar to "grow". This is going to be an interesting couple of months!

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SanDust said:

You've come a long ways from accusing me of making it up when I told you that winter was going to take a bite out of the Leaf's range. At least you're now asking why.

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Links needed to substantiate your accusation. Untill then I call this BS.

Afterall I started a thread on this question last year. It has been common knowledge for a long time that temperature will reduce range (the question was always how much & the physics behind it).

SanDust said:

Throw in reduced regen due to increased losses, plus some wind for good measure, and it's not too hard to end up with a 25% hit to the range. Throw in heating and that can go to 30% and even up to 40%.
The other good news is that, unlike heat, which will kill the battery, cold just reduces it's performance.

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With all those factors you mentioned, I've only lost 10%, nowhere near 25%. Heat will NOT kill the battery pack UNLESS it is 120 or hotter for 24 hours or more. Our summers will NOT hurt our battery packs, that's just FUD. So when you say 'heat', please quantify or it's just FUD.

Ok, perhaps stupid questions, but I don't understand batteries well. I do know the stupidest question is the one that wasn't asked. All of these questions assume it is cold out, say below 30F.

If you can charge the battery when it is warmer, say midday instead of after midnight, will you get more energy into the battery pack?

Is it better to charge right after driving, while the battery has some heat from use if you want 100%? Likewise would it be better to start driving as charging ends to gain the heat produced when charging?

If you heat the cabin to 90 mid-charge, will that aid in getting more energy in the battery?

Last question is a scenario - You are headed to a mountain top to go skiing. It is 55 degrees where you live, you drive up to the resort which has temps below 30F. and will have an all downhill run to get home, so no need to charge as long as you can get started. You get there with 2 bars showing, say 20% SOC.

LEAFfan said:

With all those factors you mentioned, I've only lost 10%, nowhere near 25%. Heat will NOT kill the battery pack UNLESS it is 120 or hotter for 24 hours or more. Our summers will NOT hurt our battery packs, that's just FUD. So when you say 'heat', please quantify or it's just FUD.

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If you're seeing a 10% reduction in range during the first week of November I may have underestimated the range hit. Next you'll be saying you don't understand how a 20 MPH head and tail wind will increase the energy needed to overcome drag by 30%.

As for heat, any operating environment (not ambient temperature) over 70F is potentially an issue. The hotter the cells get and the longer they stay hot the shorter their life will be. Given the complete lack of a thermal management system on the Leaf, Nissan will end up replacing some batteries.

As for FUD, the last time you mentioned that, you and and EVNOW were proclaiming that the Leaf's battery pack had a capacity of 32 kWh and that anyone who had a different view was spreading FUD. Maybe history does repeat itself.

The cabin is completely isolated from the battery pack so heating the cabin will have essentially no affect on the pack.

Caracalover said:

If you heat the cabin to 90 mid-charge, will that aid in getting more energy in the battery?

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TomT said:

The cabin is completely isolated from the battery pack so heating the cabin will have essentially no affect on the pack.

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It would be an interesting mod to have some forced ventilation of the batteries.

Nissan made the choice to go with no thermal management of the pack (other than the Cold Weather Package heater that kicks in at about -4F) and, in fact, the pack is sealed and under slight positive pressure.

Herm said:

It would be an interesting mod to have some forced ventilation of the batteries.

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LEAFfan said:

With all those factors you mentioned, I've only lost 10%, nowhere near 25%.

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Well, it's nice that you're not having much loss, but that makes you the exception to what should be happening, and in my case IS happening. The difference in my observed efficiency -*without* the climate control running- between ambient of 70* and ambient of 45* is 4.3m/kwh on the dash and about 70m range down to 3.5m/kwh and about 58m range. That's around 20% down in both cases, and consistent with about 25% down by the time it drops into the 30's.

I hope you continue to have such great luck with yours, but I'd also hope you could avoid setting unrealistic expectations for readers who don't have their leafs yet. If I bought my leaf on the edge of warm-air range based on owners insisting that cold-air range wasn't much shorter, it would set me up for an extremely negative experience when winter hit.

Heck, even with that expectation, when it hit I still found it a bit surprising; took me a couple days to really adjust my expectations. Luckily it doesn't interfere with my range, so no problem there... although I may have to up to 100% charge on a more regular basis when it gets colder (right now I'm 100%-ing on Fridays only).

SanDust said:

LEAFfan said:

With all those factors you mentioned, I've only lost 10%, nowhere near 25%. If you're seeing a 10% reduction in range during the first week of November I may have underestimated the range hit.
As for heat, any operating environment (not ambient temperature) over 70F is potentially an issue. The hotter the cells get and the longer they stay hot the shorter their life will be. Given the complete lack of a thermal management system on the Leaf, Nissan will end up replacing some batteries.
As for FUD, the last time you mentioned that, you and and EVNOW were proclaiming that the Leaf's battery pack had a capacity of 32 kWh and that anyone who had a different view was spreading FUD. Maybe history does repeat itself.

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Underestimated? LOL, 25% loss is OVERESTIMATING range loss. 10% is nothing and that's only because of the denser air, nothing else. Show me the proof for your 'over 70' FUD. There is no way you can know ANY batteries will be replaced because of being over 70 degrees. That's just ludicrous. And show me the quote where we said 32kW h battery pack. I believe we said 28 and we were really close. It's 28.8kW h. That's straight from Nissan to the EEs that were involved with the AZ testing. There's a lot of things you seem you think you know, but you really don't.

defiancecp said:

LEAFfan said:

With all those factors you mentioned, I've only lost 10%, nowhere near 25%.

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Well, it's nice that you're not having much loss, but that makes you the exception to what should be happening, and in my case IS happening. The difference in my observed efficiency -*without* the climate control running- between ambient of 70* and ambient of 45* is 4.3m/kwh on the dash and about 70m range down to 3.5m/kwh and about 58m range. That's around 20% down in both cases, and consistent with about 25% down by the time it drops into the 30's.
I hope you continue to have such great luck with yours, but I'd also hope you could avoid setting unrealistic expectations for readers who don't have their leafs yet. If I bought my leaf on the edge of warm-air range based on owners insisting that cold-air range wasn't much shorter, it would set me up for an extremely negative experience when winter hit.
Heck, even with that expectation, when it hit I still found it a bit surprising; took me a couple days to really adjust my expectations. Luckily it doesn't interfere with my range, so no problem there... although I may have to up to 100% charge on a more regular basis when it gets colder (right now I'm 100%-ing on Fridays only).

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It isn't misleading anyone. I've given our temps when I've had the reduction. I'm sure it will reduce more when it gets to 30 or 40 because the air will be even denser. I will let you know what happens.

TomT said:

Nissan made the choice to go with no thermal management of the pack (other than the Cold Weather Package heater that kicks in at about -4F) and, in fact, the pack is sealed and under slight positive pressure.

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Yeah you would lose the pack seal, but it would be an interesting mod once the warranty is up on the Leaf. Another way to do it would be to run a freon loop with a metal pipe against the battery case.

Anyone put a remote temperature sensor on the battery case?

have talked about this extensively recently and last spring. before we begin;

1) no change in driving destinations, patterns, speeds, routes, etc.

2) no climate control
3) no heater

4) no defrost (other than occasional bursts lasting less than one minute) used it exactly 3 times in past 8 days (off on normal. was sick and did virtually nothing for 3 days)

5) CLIMATE CONTROLS ARE NOT A FACTOR IN MY STATS

ok. hopefully that clears up some stuff.

so, have already presented this information several different ways. so am trying another tactic

below is miles/kw reading on my car (this sample is typical if you prefer a different date based on your stats for temps in the area, please ask) from April 1-8. the only thing i dont know is how much climate control has been used.

4.8
4.7
4.5
4.2
4.8
4.4
5.6
4.9

now lets take a random week during Summer when temps are likely to have highs ranging from mid 70- to low 80's (average summer high max'es out at 78º for August) stats start from Aug 1st and like April are consecutive days. the 4.5 day is 64 miles, 90% freeway at 65+ mph. the rest are my normal drive around town stuff.


5.7
4.5
5.3
5.6
5.3
5.4
5.8
5.9
6
5.9
5.6

now lets post the present starting Nov 1 to yesterday

5.0
4.4
3.8
3.9
4.2
4.6
4.7
4.3
4.8
4.6

the 3's are generally when SO drives. she turns the heat on full blast as she enters the car and leaves it that way. she quite frankly, does not know the meaning of conservation. (she also cannot turn off a light)

i have purposely not used climate controls to help illustrate this point (thank you Sherpa lined hoodie for your warmth!!) and it is usually warm enough at this time of year to get away with that.

bear in mind, its very cold in the mornings with temps in mid 30's typical. but my morning commute is done on empty streets from a garage fresh from hot shower with full mug of hot coffee, so i am comfortable. my 10 minute commute is not long enough to get cold.

the afternoon, i am not so lucky. the commute is generally 14 to 25 minutes, the car sits out in 10 acre parking lot all day and if it has been raining, cloudy, etc. the car will pretty much be in the upper 40's to low 50's which is typical at this time of year at 5 PM.

when it gets colder and i start to use heat to survive, my numbers will drop to the low 4s which occasional dips into the 3's (this is street speeds, freeway never reaches the 4's)

this is why i state (frequently) that my winter range is 75 miles which is based on 3.5 miles per k.