Cold weather -> 0 battery temperature bars

[BoulderLeaf]

Hi all,

I have a question I was hoping to get some help with. It has been unseasonably cold here the last few days, and I've been trading off garage time between the Volt and LEAF. It was the LEAF's turn outside last night, and this morning it was -8 deg F... I had read that the battery heater turns on (even when not plugged in as long as the battery charge is above 30% SoC) before it gets to this temperature (and I parked it with about 85% SoC). However, when I went to move the LEAF into the garage this morning to plug in, there were 0 battery temperature bars showing in the display. Is this normal? Should the battery heater have kept it at a certain minimum number of temperature bars?

And lastly, now that I think about it... I hope this didn't hamper my warranty at all. Although, I think Nissan says that you shouldn't leave it unplugged for longer than 7 days (I think?) at low temperatures, which I definitely did not do (ie, I only left it unplugged for 1-2 days, and not all of that time below 0).

Am I OK? Did I miss something or could have done something better?

Thanks!

 

[ksnogas2112]

I'd like input from some others, but I THINK you're ok. I was at 2 temp bars two weeks ago at 15*F. As far as I know the battery heater won't run enough to actually heat the battery to temp bars but just keeps it from actually freezing.

It would be nice to hear from some of the others on the forum on this.

Also at 3 temp bars at lunch today @1400 hrs after leaving house with 4 battery temp bars and 100% charge.

 

[nosuchthing]

BoulderLeaf:
Just keep it plugged in during freezing temps so you don't turn your EV into a...
BroderLeaf :twisted:

 

[TonyWilliams]

I would plug the LEAF in and leave it charged at 80%.

The heaters come on at -20C / -4F, and heat the battery to -10C / +14F, then repeat.

 

[XeonPony]

well at -30c (-22f) I had two temp bars, I did notice the high beam switch sticks at -30c! they misserably failed at the heating system! really really needed a fuel based heater, even if it killed the zerro emissions lable at least for the canadian market! it will get to -40 (It is the same in farenhit at that point) at that point I think the car will be near un usable.

 

[dgpcolorado]

The temperature range for the temp bar gauge is somewhat uncertain but the original chart supplied by Nissan in the 2011 Service manual is here:
http://www.mynissanleaf.com/wiki/index.php?title=Battery#Battery_Temperature_Gauge" onclick="window.open(this.href);return false;

A later chart showed a lot of overlap in the temperature ranges for each bar. However, for the question of whether seeing zero temp bars in extreme cold weather is normal, the answer is "yes". If the table in the link above is valid, the first bar won't come on until the battery temp is ~5ºF. And if the battery didn't get down to -4ºF the battery heater won't come on. If your battery temperature started out well above those temperatures it takes a LOT of time to get down to ambient temperature because the battery has significant thermal mass. If you are charging, even at Level 1, it won't get to ambient because charging heats it.

So, just because the OAT was -8ºF doesn't mean that the battery got that cold. It is unlikely that a single overnight at that temperature got the battery cold enough to trigger the battery heater, although it is possible. In the future, in extreme cold temperatures it is best to leave the car plugged-in, even at Level 1. Charging overnight will help warm the battery. If it gets too cold it will not charge well. In that case driving the car will warm it up so that it can charge again.

jkirkebo was the first to report on driving a LEAF in very cold temperatures a couple of years ago. Here is one of his observations:
http://www.mynissanleaf.com/viewtopic.php?f=31&t=7124&start=57" onclick="window.open(this.href);return false;
He did have another post about zero temp bars but I can't find it now.

You won't have much trouble with very cold weather in Boulder (usually) but the folks like XeonPony in the "frozen north" will have some interesting experiences if they can't garage the LEAF. Lithium batteries just don't work very well below -15ºC. Even with the battery heater that comes on at -20ºC the car will be difficult to charge in extreme cold and the range will be greatly reduced for a variety of reasons (of course).

 

[manitou820]

I'm down in Manitou Springs and last Thursday night I couldn't make it up the hill so I had to park my Leaf outside, unplugged, in -6F temps all night with a 55% SOC remaining. When I got to the car in the morning it was still -6F, I had two bars on the battery temp, and 53% of the battery was remaining.

 

[ksnogas2112]

I don't recall the service manual on what temp bars are for what temp. However, after soaking the cold yesterday, 10*F in the a.m. and 20*F when I left the office and no travel in between, I left the house with 4 battery temp bars and backed the car out at the office with 2. But almost immediately when starting up the hill the temp bar jumped to 3. So 15-20*F is the border for 2-3 bars but that may also depend on the starting temp of the battery since we all know it takes forever to heat it and forever to cool it. After arriving home with 3 temp bars and plugging in, we're back at 4 this a.m. with 15*F but whoo might break the freezing point at lunch.

Bundle up folks, this is going to be a bad winter.

 

[Den]

If you have winter package, the battery is ISOLATED! So it takes time to cool down the battery and its temperature is not same as outside air temperature.

I also saw zero temp. bars last winter when it was about -20C (after a couple of days with less than -10C and car always outside). Now I always garage it for night and still never saw less than 4 bars this winter even it was about -10C yesterday (and up to -15C at night but it was garaged then). So whole day at about -10C isn't enough to fall below 4 bars, when last winter when it always lived outside I guess I would have permanent 2 bars at this point.

 

[BoulderLeaf]

Thanks for the replies everyone. I'm now housing the LEAF in the garage and hopefully we won't be getting that cold again any time soon.

I did end up taking a trip in the LEAF later that day while it was about 4 degrees. This trip normally would take 2 bars, but it ended up taking 5 (or 6, I don't recall exactly). And on the way to my destination, at 4 degrees, the number of battery bars crept up until about 2 bars... so I guess that was the result of the battery heater?

In any case, things seem to be fine. Thanks!

 

[LEAFfan]

Bundle up folks, this is going to be a bad winter.

Ya, I feel for ya. I had those when I lived in the Midwest...so da** happy now.

 

[dgpcolorado]

... And on the way to my destination, at 4 degrees, the number of battery bars crept up until about 2 bars... so I guess that was the result of the battery heater? ...

If you are talking about the temperature bars on the left side of the dash, the likeliest explanation for an increase is just driving the car. That heats the battery significantly. According to specs, the battery heater won't come on until the battery gets to -4ºF, and you would have to cold soak the car for some time at a temperature somewhat lower than that to get it that cold.

Both charging the car and driving it will heat the battery so under normal use it is very unlikely that the battery will ever get to ambient temperature. In extreme cold weather, if you find it difficult to charge (very slow due to cold) driving the car for a time will heat the battery and improve the charging ability. That being the case, it is best to not let the battery level get too low when parking in extreme cold. Rather, you should charge some as soon as you arrive to get some electricity back in the battery while it is still warm from driving.

Now that you are using a garage this shouldn't affect you. But if you park for a weekend outside in below zero temperatures, be aware of these issues.

 

[GregH]

... And on the way to my destination, at 4 degrees, the number of battery bars crept up until about 2 bars... so I guess that was the result of the battery heater? ...

If you are talking about the temperature bars on the left side of the dash, the likeliest explanation for an increase is just driving the car. That heats the battery significantly. According to specs, the battery heater won't come on until the battery gets to -4ºF, and you would have to cold soak the car for some time at a temperature somewhat lower than that to get it that cold.

Both charging the car and driving it will heat the battery so under normal use it is very unlikely that the battery will ever get to ambient temperature. In extreme cold weather, if you find it difficult to charge (very slow due to cold) driving the car for a time will heat the battery and improve the charging ability. That being the case, it is best to not let the battery level get too low when parking in extreme cold. Rather, you should charge some as soon as you arrive to get some electricity back in the battery while it is still warm from driving.

Now that you are using a garage this shouldn't affect you. But if you park for a weekend outside in below zero temperatures, be aware of these issues.

Driving and especially charging will heat the battery all the more so in cold temps as the impedance of the battery is much higher when cold. Some might see this as reduced efficiency, but if your goal is to heat up the battery then maybe it's not such a bad thing to have all that waste heat...

 

[dgpcolorado]

Driving and especially charging will heat the battery all the more so in cold temps as the impedance of the battery is much higher when cold. Some might see this as reduced efficiency, but if your goal is to heat up the battery then maybe it's not such a bad thing to have all that waste heat...

Interesting. Yes, definitely not "waste" heat for those of us with cold batteries.

Off topic: Is it true that Leaf DD won't show battery temperatures below 0ºC? I've had some sensors down to that level but I was hoping to monitor the battery temperature at well below freezing temperatures when I park outside in very cold weather. (But so far garage + driving + charging is keeping the battery at a toasty 0.5 - 5ºC.)

 

[GregH]

Off topic: Is it true that Leaf DD won't show battery temperatures below 0ºC? I've had some sensors down to that level but I was hoping to monitor the battery temperature at well below freezing temperatures when I park outside in very cold weather. (But so far garage + driving + charging is keeping the battery at a toasty 0.5 - 5ºC.)

Hmmm.. good question. Turns out the LeafDD only displays calculated (ie xx.x degrees C) temps between 0 and 57C.. and even then the precision is probably not 0.1C down near the bottom (or top) of that range... If you do a long press of the button on page 2 it will toggle to the raw AD values and the car's own calculated temp in whole degrees C... Not sure how they deal with <0 C. If the LeafDD concludes it's calculated value doesn't match the car (say the car says 4 and the LeafDD thinks 3.9) it will add a little + or - after the value to show it knows it's a bit off.

If you can get a screen shot of both versions of page 2 on a really cold day and post it on the LeafDD thread I'd be curious to see the error. Coastal California doesn't present me many data points on extreme temperature.

 

[XeonPony]

well -34 and still had 2 temp bars, and range dropped like a lead brick in ethonol during the drive to work.

 

[LeftieBiker]

Thanks for the replies everyone. I'm now housing the LEAF in the garage and hopefully we won't be getting that cold again any time soon.

I did end up taking a trip in the LEAF later that day while it was about 4 degrees. This trip normally would take 2 bars, but it ended up taking 5 (or 6, I don't recall exactly). And on the way to my destination, at 4 degrees, the number of battery bars crept up until about 2 bars... so I guess that was the result of the battery heater?

In any case, things seem to be fine. Thanks!

It was probably the result of the battery drain. Anything above a 'trickle drain' will heat the battery pack. For that reason, a short drive with the heat blasting is probably a better way to warm the pack than relying on the 300 watt heater.