One more winter range post- 33*, 80% to 0 bars: 32.8 miles

[abasile]

Well persueing the idea above that I could get better range from a warmer battery that was charging up until I started driving, today was disappointing. Charged right up to the time to go to work and return and each time the battery temp readings, as crude as they are, were identical. Maybe the result will be better with a 220 v charger when I get one organized.

L1 or L2 charging to 80% will generate some heat, but not as much (in my experience) as driving, which typically pulls much more current through the battery. Charging to 100% should produce a bit more heat.

Also, keep in mind that the fifth battery temperature bar won't light until 55°F. You could heat the battery significantly and still not see a rise on the gauge.

In spite of the cold we've been having (looks like tonight's low will be around 20°F again), range has not at all been an issue for us in our day-to-day driving. I would say that, rather than falling off a cliff, the range degrades gently as temperatures drop. My disclaimer is that we have not been using the climate control much, as we are at a high altitude and our cold air is less dense and is usually dry; as a result, my experience might be more relevant to other folks in the Mountain West than in the humid East.

 

[DaveEV]

Well persueing the idea above that I could get better range from a warmer battery that was charging up until I started driving, today was disappointing. Charged right up to the time to go to work and return and each time the battery temp readings, as crude as they are, were identical. Maybe the result will be better with a 220 v charger when I get one organized.

Edit I should add that the temp guage was unchanged every day since I took delivery, immediatley after charging, after sitting idle, after driving ... all the same readings.

The battery temperature gauge segments in the center of the gauge (segments 4-7) cover very wide temperature ranges, about 20-25 degrees. The battery also weighs a lot, it takes some time to get it to change temperature. You will only see the battery gauge change if near a transition temperature or at very cold (0-3 bars) or very hot (8-12 bars) temperatures.

Battery Temperature Gauge

 

[GaslessInSeattle]

a month ago I would have said you were crazy saying the temp doesn't change range much for the battery, but now that I'm prewarming and using foot/defog with CC off, It's shocking how much energy it turned out that CC was eating up! Now we are back to 4.2 MPkW, summer was 4.6, turns out the cold so far isn't the culprit per say, it's the climate control ... our worst, with CC on last month was 3.3 MPkW. As long as we are driving at moderate speeds, there is adequate circulation to defog without the fan or power defrost on. It's so unintuitive to turn Climate control off, but if you need the range, it's really quite doable.

Well persueing the idea above that I could get better range from a warmer battery that was charging up until I started driving, today was disappointing. Charged right up to the time to go to work and return and each time the battery temp readings, as crude as they are, were identical. Maybe the result will be better with a 220 v charger when I get one organized.

L1 or L2 charging to 80% will generate some heat, but not as much (in my experience) as driving, which typically pulls much more current through the battery. Charging to 100% should produce a bit more heat.

Also, keep in mind that the fifth battery temperature bar won't light until 55°F. You could heat the battery significantly and still not see a rise on the gauge.

In spite of the cold we've been having (looks like tonight's low will be around 20°F again), range has not at all been an issue for us in our day-to-day driving. I would say that, rather than falling off a cliff, the range degrades gently as temperatures drop. My disclaimer is that we have not been using the climate control much, as we are at a high altitude and our cold air is less dense and is usually dry; as a result, my experience might be more relevant to other folks in the Mountain West than in the humid East.

 

[padamson1]

It also appears that cold affects the regen. I have a 900' altitude change from my house down to work. I charge 80% everyday so I can get some regen on the way down. Up until it got cold I only get 1 bubble for the first 2mi, then up to 2, reaching 3 near the bottom then back to 2 (b/c the battery is back to 10 bars) until I drain the battery down again and it returns to 3 around 8mi, then 4 bubbles of regen just before I get to work. BTW the double circle indicator to indicate the max regen is really cool.

Now it's around 45deg or so in my garage and I've got one less temp bar (4) the whole way to work. I get to a max of 3 regen bubbles just before I the last traffic light before work. Net effect is that when I get to work have one less battery bar on the same drive, with no CC. If I have to use the defroster I don't seem to lose much more (same bars) but I don't have an SOC. Basically I lose a bar of regen when I go down the hill because it never gets over 1 bubble the whole way down the hill.

It is counter intuitive to me that the regen capability is limited when its cold, I thought it would be beneficial to use regen to heat the battery up to a better temp. Apparently I am mistaken.

 

[brent]

It also appears that cold affects the regen. I have a 900' altitude change from my house down to work. I charge 80% everyday so I can get some regen on the way down. Up until it got cold I only get 1 bubble for the first 2mi, then up to 2, reaching 3 near the bottom then back to 2 (b/c the battery is back to 10 bars) until I drain the battery down again and it returns to 3 around 8mi, then 4 bubbles of regen just before I get to work. BTW the double circle indicator to indicate the max regen is really cool.
.

I have seen that I don't get any re-gen for about the 1st 10 minutes of my drive. I have a few hills that rise and fall 50-75 feet within the first mile of home, and the re-gen is zero through that strech. By the time I'm 15 minutes from home, it all seems normal.

I tried playing with the CC timer and I was surprised to see that it was not possible to get it out of re-circ mode while pre-heating. So now I am looking into getting the window guards available in Japan. We have an air shipment of machine parts coming over in January and I have asked the supply to find the price on a set of these. Hmm that didn't work, putting in the picture. Anyway they are on this page, about half way down on the red Leaf. This would allow the window to be left open an inch and keep most of the rain / snow out.
http://ev.nissan.co.jp/LEAF/OPTION/dop.html" onclick="window.open(this.href);return false;
I'll post here what they cost in case anyone else wants to try some

 

[abasile]

It is counter intuitive to me that the regen capability is limited when its cold, I thought it would be beneficial to use regen to heat the battery up to a better temp. Apparently I am mistaken.

In colder temperatures, the rate at which chemical reactions can take place in the battery is reduced. As charging and discharging involve chemical reactions, a cold battery is not capable of delivering as much power as a warm battery, nor is it able to be charged as quickly. Typically these batteries can be discharged much more rapidly than they can be charged, which is why we see our regenerative braking limited in the cold but not our power except in extreme cold. (Particularly in warmer temperatures, the LEAF's battery pack is capable of delivering significantly more than 80 kW of power, but supposedly the motor is rated at only 80 kW.)

It is also my impression that Nissan is being conservative with respect to the amount of regenerative braking that the car allows. This of course is to help prolong the life of the pack. Allowing more regen so as to heat the pack might be good for range in the short term, but I'm not sure that it would be ideal for battery life. Perhaps someone with a better knowledge of battery chemistry than myself can comment here.

One good thing about keeping a LEAF in the cold is that the secondary chemical reactions that cause gradual, permanent capacity loss will take place more slowly. In other words, the calendar life of the pack should be longer. Given that nobody has definitively observed capacity loss yet (as far as I know), it'll probably be a few years or longer before anyone notices a significant difference, though.

 

[brent]

I watched the regen indicator more carefully today, and there was no regen until after the first range update had dropped the range. So I am guessing the logic in the system will not try to regen until it detects a drop to 98% of full charge. Since I'm still in my first week of Leafing and in Canada, I've never seen warm weather resonse yet. More observation required

 

[amtoro]

I just opened a file with Nissan and they will try to research it with the engineers and keep the information for future reference.

The question is:
The recommended charging regime for maximum battery life is 80% all the time, mainly due to the heat produced during the las 20% of charging. Timing the charging session to end 60 to 30 minutes before departure time would allow to have a warmer battery at the start of the morning commute, but would it help the range, or still be detrimental to the battery to charge to 100% during winter months?

Let's see what they can answer

 

[jkirkebo]

I started the other day with only one battery temperature bar. The battery was charged to 80% but I got no regen bubbles at all since the battery was so cold. The first bubble appeared at about 70% SOC.

I did try to charge the battery to 100% in the morning but gave up as the charging power was less than 1kW and so it would have taken around 4 hours to charge from 80 to 100%.

 

[brent]

I have been monitoring the charge time estimates and it does seem to be temperature sensitive.

Plug in at 50% and it says 8 hours
One hour later it says 6 1/2 hours to go
One hour later it says 5 hours to go.

I'm guessing the battery temp is going up a bit and it's therefore accepting charge faster.

 

[abasile]

I started the other day with only one battery temperature bar.

Wow! I think that is a forum record for lowest battery temperature! (I've never seen lower than four bars.) How cold is it where you are in Norway? Did you gain battery temperature bars after driving the car? Do you have the Cold Weather Package?

The battery was charged to 80% but I got no regen bubbles at all since the battery was so cold. The first bubble appeared at about 70% SOC.

I did try to charge the battery to 100% in the morning but gave up as the charging power was less than 1kW and so it would have taken around 4 hours to charge from 80 to 100%.

That's pretty dramatic. Was your motor power limited as well? I'd be surprised if the charge rate were limited to 1 kW at 80% SOC but the car still allowed full acceleration (80 kW).

 

[ERG4ALL]

I'm looking forward to amtoro's answer. I've started to charge to 100% every day because I do enjoy the warmth and it is a necessity for keeping the windshield de-fogged. But the charging occurs in a garage that is anywhere from 40 - 50 degrees. The hope is that the battery is cool enough that charging to 100% won't be detrimental. I have the timer set to go off at 5:50AM and to come on at 6:00AM so the car charges anytime I plug it in. It may be better to reset the timer to start charging at 11:00PM and off at 6:00AM in order to make sure the battery has had time to cool down from daily use before it is recharged. Any thoughts?

 

[abasile]

I have been monitoring the charge time estimates and it does seem to be temperature sensitive.

Plug in at 50% and it says 8 hours
One hour later it says 6 1/2 hours to go
One hour later it says 5 hours to go.

I'm guessing the battery temp is going up a bit and it's therefore accepting charge faster.

First of all, I haven't found those 120 V charging time estimates to be all that precise. Also, in my experience, the car has charged in less time than predicted in the cold because of the battery having less capacity, unless it's so frigid as in jkirkebo's case that the charge rate has to be limited to protect the battery. In southern Ontario (I grew up in Western New York), winter lows don't tend to be that extreme. (Northern New York, north of the Adirondacks, is another matter; Norway-like temperatures aren't uncommon there.)

 

[DaveinOlyWA]

a month ago I would have said you were crazy saying the temp doesn't change range much for the battery, but now that I'm prewarming and using foot/defog with CC off, It's shocking how much energy it turned out that CC was eating up! Now we are back to 4.2 MPkW, summer was 4.6, turns out the cold so far isn't the culprit per say, it's the climate control ... our worst, with CC on last month was 3.3 MPkW. As long as we are driving at moderate speeds, there is adequate circulation to defog without the fan or power defrost on.

I got my Leaf in jan. So that is 2nd winter in Leaf plus 4th driving EV. it is all expected but then again my Prius is now vetting 45 mpg down from 55 mpg crom july. Its simply the "zeason"


In jan. So 2nd winter and 4th with EV

 

[abasile]

I'm looking forward to amtoro's answer. I've started to charge to 100% every day because I do enjoy the warmth and it is a necessity for keeping the windshield de-fogged. But the charging occurs in a garage that is anywhere from 40 - 50 degrees. The hope is that the battery is cool enough that charging to 100% won't be detrimental. I have the timer set to go off at 5:50AM and to come on at 6:00AM so the car charges anytime I plug it in. It may be better to reset the timer to start charging at 11:00PM and off at 6:00AM in order to make sure the battery has had time to cool down from daily use before it is recharged. Any thoughts?

The standard advice is, charge to 100% whenever you need to, even if that's every day. Plenty of LEAF owners are doing this. What's bad for the battery is leaving it sitting at 100%. Time your charging so that the battery reaches 100% as close as possible to your departure time.

 

[TonyWilliams]

I started the other day with only one battery temperature bar.

Was the outdoor temperature between -9C and -12C, or colder than that (and the battery was heated by charging) ?

Segments Degrees C (F)
12 60 (140)
11 57.5 (135.5)
10 55 (131)
9 52.5 (126.5)
8 50 (122)
7 36.8 (98.2)
6 23.5 (74.3)
5 10.3 (50.5)
4 -3 (26.6)
3 -6 (21.2
2 -9 (15.8)
1 -12 (10.4)
0 -15 (5)

 

[DaveEV]

I watched the regen indicator more carefully today, and there was no regen until after the first range update had dropped the range. So I am guessing the logic in the system will not try to regen until it detects a drop to 98% of full charge. Since I'm still in my first week of Leafing and in Canada, I've never seen warm weather resonse yet. More observation required

In "normal" temps you never get any regen at 100% charge. Typically you only get full regen when the battery gets down to about 80% charge.

When the battery is cold, regen is limited at even 80% charge. Even here the first regen bubbles goes on/off the first couple miles on a 80% charge and it's not that cold.

 

[jkirkebo]

The morning I had one bar the car had been sitting for three days and the temperature was -16C (3F). I did not gain any bars from my aborted charging attempt, I had to prioritize heating the car up instead and thus clearing the (very hard) ice from the windshield.

Shortly after drivng away I got the second bar then the thord some time later and the fourth a little after an hour of driving. The fifth bar I got after fast charging for 70(!) minutes.

I do have the CWP but the battery heater hasn't ever kicked in yet.

 

[padamson1]

It is counter intuitive to me that the regen capability is limited when its cold, I thought it would be beneficial to use regen to heat the battery up to a better temp. Apparently I am mistaken.

It is also my impression that Nissan is being conservative with respect to the amount of regenerative braking that the car allows. This of course is to help prolong the life of the pack. Allowing more regen so as to heat the pack might be good for range in the short term, but I'm not sure that it would be ideal for battery life. Perhaps someone with a better knowledge of battery chemistry than myself can comment here.

I've started 'lying' to the timer and setting it to complete the charge 1.5hr after I expect to leave so that I leave my house with 7 bars. This lets me take advantage of my hill and I end up with the same range when I get to work as when I left with 8 bars.

I knew there was a reason for regen being clipped when the pack was cold, thanx for the explanation.

 

[abasile]

The morning I had one bar the car had been sitting for three days and the temperature was -16C (3F). <snip>

Shortly after drivng away I got the second bar then the thord some time later and the fourth a little after an hour of driving. The fifth bar I got after fast charging for 70(!) minutes.

This is very useful cold-weather data; thank you! I am pleased to see confirmation that driving with a cold pack can raise its temperature significantly. We need more Quick Chargers here in the States!