Questions about leaving car plugged/unplugged in winter.

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Z

ZF911

New member
Joined
Sep 3, 2019
Messages
2
Location
Michigan
I just purchased a used 2016 SV over the weekend. I love the car, but my biggest concern is how it will handle Michigan winters. I see that a common piece of advice is to only charge to 80-90% and stop, to give the battery a longer lifespan. My user manual also mentions keeping the car plugged in during cold weather so that the battery can heat itself from the power source instead of draining itself. It seems like that would go against the idea of not fully charging the battery. As far as specifically in the winter and below freezing temps, what is the better choice? Charging to full so the battery can warm itself from the charging cable, or letting the battery warm itself and continuing to unplug at 80%? I'm afraid of having no range in the morning if it spends all night warming itself unplugged, but without going through it, I really don't know how much power that requires. If I used a charge timer to limit charging, would the charge cable still be able to warm the battery, or would the timer cut off all power use from the cable?

Some additional questions along the same line: I'm currently using the included trickle charger, until I can get the work done to install a level 2. I'm currently using an extension cord, as it's the only way to keep the plug and box inside and safe from rain/snow. Is there any issues with using an extension cord, or any better ways to weatherproof the charger for outside use? I noticed the manual advises against it, but the dealership told me it was no problem. And if the extension cord is okay for normal charging, would the cold weather battery heating cause any other issues with an extension cord?

And last cold weather question. I know leaving the car plugged in for days at a time can kill the 12 volt battery. If I was leaving the car for several days or longer without driving it in cold weather, could the cold do any permanent damage assuming the charge got low enough that the battery could no longer heat itself? I know it'd have to warm up to start, but other than that would me leaving town for a week in the harsh winter ruin my battery?
 
Things aren't as bad as you think. First, the battery warmer only comes on when the pack - not the ambient air - temperature is in the single digits Fahrenheit. Second, even running around the clock, the warmer only uses 300 watts, and so it takes a few days to drain the pack. So your best strategy would be to charge the car to about 90% in Winter (cold isn't as bad for the pack anyway) and then charge it for a few hours once a day, as needed. This should also eliminate the risk of the 12 volt battery dying, as it doesn't get drained while the car is charging. As long as you don't need to leave the car for a week in frigid (below about 7F) temps, you should be fine. If you need to do that, look into finding a place to park it where the temps will be above 10F. Most unheated garages will work for that.
 
The topic of extension cords has been discussed frequently: https://www.mynissanleaf.com/search.php?keywords=extension+cord&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
 
Don't worry about taking the battery to 100% when it is really cold out. The low temperature will significantly slow battery degradation, and you will want all the charge you can get when you need to put 3 kW into the heater just to keep the windows from frosting up. I've also found the charge timer seems to get confused when it is very cold, as my 2016 SL didn't end up as charged as it was supposed to be the on the first -25°C morning of the winter. After that, I just disabled the charge timer until the weather warmed up, and always came out to fully charged car. (Almost fully charged anyways, I only have a 16 A L2 EVSE, so it can't quite keep up with the demand when preheating).

As you are probably aware, winter range sucks. Expect 40-50% of summer range for urban driving in very cold conditions, unless you are willing to bundle up and manually scrape the windows to be able to see. Highway speeds will be a bit better, but still substantially worse than in summer. Unless your daily drive is quite short and you are using less than 25% charge (which will become 50-60% when it is below -25°C out), you will want to get that L2 installed before winter. An overnight L1 is only good for about 2/3 of a charge (less if 300 W of the 1440 W are going to the battery heater) and a preheating will take more energy from the battery than from the EVSE if you are only on L1.

An extension cord for the EVSE is not ideal, but if the wire is at least 14 AWG (12 AWG if over 50 feet) and the plugs are secure and don't get hot while it is in use it will be fine.

Tires will be another winter issue. Even if you normally don't use winter tires, you will want them for the Leaf. All all-season tires are mediocre at best in winter, but the stock Leaf tires are terrible. Below -15°C they pretty much turn into hockey pucks.
 
An overnight L1 is only good for about 2/3 of a charge (less if 300 W of the 1440 W are going to the battery heater) and a preheating will take more energy from the battery than from the EVSE if you are only on L1.
Click to expand...


A couple of clarifications. The L-1 EVSE from Nissan uses about 1300 watts, but not all of that gets into the battery. With the battery warmer drawing 300 watts. the battery will get no more than maybe 900 watts. Also, the climate control draws power only from the battery, always - not from the EVSE. If the amount of charge current provided by the EVSE exceeds the amount being drawn by the climate control, then the battery gains charge. This usually happens only when the EVSE is providing more than 16 amps at 240 volts. With a 120 volt 1.2kw charge going in the battery will definitely suffer a net loss of charge. I had good luck preheating the car for only 2 or 3 minutes, losing 3 or 4% charge in the process. That made the interior relatively mild and gave the seat(s) and steering wheel time to start to get warm.
 
ZF911 said:
I just purchased a used 2016 SV over the weekend. I love the car, but my biggest concern is how it will handle Michigan winters.
Click to expand...

I just bought a 2017 SV, so I'll join you into the mysteries of winter operation.
Where in Michigan are you located?
 
You are WAY over-thinking things. EVs handle extreme cold better than ICE cars (with the understanding of decreased range compared to warm weather operation). I suggest spending some time searching/reading the many topics/discussions related to your questions: there's lots of good info on this forum!
 
I appreciate all of the information. My current daily commute is a total of 34 miles, when I'm driving in eco mode, and not using the highway or climate control, I'm using 35% of the battery each day. I'm intentionally only charging to 75-85% and unplugging, but if winter is going to be more of a drain on power, I may let it charge a bit more.

Titanium48 said:
As you are probably aware, winter range sucks. Expect 40-50% of summer range for urban driving in very cold conditions, unless you are willing to bundle up and manually scrape the windows to be able to see. Highway speeds will be a bit better, but still substantially worse than in summer.
Click to expand...

What makes highway driving better in the winter compared to normal when it uses much more of the charge?

css28 said:
ZF911 said:
I just purchased a used 2016 SV over the weekend. I love the car, but my biggest concern is how it will handle Michigan winters.
Click to expand...

I just bought a 2017 SV, so I'll join you into the mysteries of winter operation.
Where in Michigan are you located?
Click to expand...

In the Flint area.
 
ZF911 said:
Titanium48 said:
As you are probably aware, winter range sucks. Expect 40-50% of summer range for urban driving in very cold conditions, unless you are willing to bundle up and manually scrape the windows to be able to see. Highway speeds will be a bit better, but still substantially worse than in summer.
Click to expand...

What makes highway driving better in the winter compared to normal when it uses much more of the charge?
Click to expand...

I'm pretty sure what was meant is that the cold-weather efficiency drop is not as severe at highway speed (hwy warm vs hwy cold), as it is at city speeds (city warm vs city cold). Due to the higher speed, you're spending less energy on heating *per mile*. Carried to the other extreme, if you sit still in a traffic jam in the cold, nearly ALL of your energy is being spent on heating. The other factor is that highway speed actually causes some battery warming due to the higher current demand, and so the batteries themselves perform better. None of this takes into account snow or slush, which will also sap power.
 
ZF911 said:
I just purchased a used 2016 SV over the weekend. I love the car, but my biggest concern is how it will handle Michigan winters.
Click to expand...

I'm a former Volt owner. In my experience, your heated seat and heated steering wheel (if you have that) will be your best friends, allowing you to use the heater for your feet and the windshield, and at a lower temperature.

I have a 38 mile round trip, but in metro Detroit, so we're probably about even for the most part.
 
New Leaf owner in Georgia here. I have a few questions about what is best to do when the Leaf will not be driven for 3-4 months over the Winter. We head to So. Florida and usually just disconnect the battery in our ICE cars. What should I do with the EV?
 
Congrats!

Be very careful using an extension cord. I started off using one but you need to monitor heat at the ends of the cord carefully, or things start melting and you encounter fire risk. Unplugging/replugging the ends of the extension cord periodically can help, but over a few months, I was encountering too much oxidation on the contacts and too much heat at the plugs.

I started parking in a less-convenient spot but with direct access to an outlet and everything stays nice and cool now.

You might consider carrying a warm blanket in the car. I started bundling up and covering my legs with a blanket and only periodically using the climate control to clear the windows. I find it more comfortable than using the heater.

You will certainly find yourself doing more charging in the wintertime. As mentioned, it takes a serious cold-soak to activate the battery heater. The pack has significant heat capacity, and it takes a pretty severe cold snap for the pack itself to get cold enough to activate the heater.

Cheers!
 
OP, what year is your Leaf? The early ones had some issues with the 12V battery being drained, especially if they had the telematics option.
The newer ones should be just fine if left for a few months. Just leave the main battery at 30% -50% charge and forget it. Unlike the lead/acid 12V battery, the main Li battery shouldn't be left at a very high or very low charge level for long periods.
 
goldbrick said:
OP, what year is your Leaf? The early ones had some issues with the 12V battery being drained, especially if they had the telematics option.
The newer ones should be just fine if left for a few months. Just leave the main battery at 30% -50% charge and forget it. Unlike the lead/acid 12V battery, the main Li battery shouldn't be left at a very high or very low charge level for long periods.
Click to expand...


Our "new" Leaf is a 2014 SL. Thank you for your advice. I have also heard that I might consider either a trickle charger on the 12V battery or just disconnect it. Of course doing the latter I probably will have to charge up the 12V separately upon our return. :D
 
Amazing1 said:
Our "new" Leaf is a 2014 SL. Thank you for your advice. I have also heard that I might consider either a trickle charger on the 12V battery or just disconnect it. Of course doing the latter I probably will have to charge up the 12V separately upon our return. :D
Click to expand...

I've left my 2014 LEAF for 6 weeks with no issues.
 
Buy a trickle charger that desulfates the battery - it keeps the battery charged and prolongs its life. I’ve used it for as long as 6 weeks and it’s nice to come home to a car ready to go and all your settings are intact, which you lose if you disconnect the 12v battery.
 
ZF911 said:
I just purchased a used 2016 SV over the weekend. I love the car, but my biggest concern is how it will handle Michigan winters. I see that a common piece of advice is to only charge to 80-90% and stop, to give the battery a longer lifespan. My user manual also mentions keeping the car plugged in during cold weather so that the battery can heat itself from the power source instead of draining itself. It seems like that would go against the idea of not fully charging the battery. As far as specifically in the winter and below freezing temps, what is the better choice? Charging to full so the battery can warm itself from the charging cable, or letting the battery warm itself and continuing to unplug at 80%? I'm afraid of having no range in the morning if it spends all night warming itself unplugged, but without going through it, I really don't know how much power that requires. If I used a charge timer to limit charging, would the charge cable still be able to warm the battery, or would the timer cut off all power use from the cable?

Some additional questions along the same line: I'm currently using the included trickle charger, until I can get the work done to install a level 2. I'm currently using an extension cord, as it's the only way to keep the plug and box inside and safe from rain/snow. Is there any issues with using an extension cord, or any better ways to weatherproof the charger for outside use? I noticed the manual advises against it, but the dealership told me it was no problem. And if the extension cord is okay for normal charging, would the cold weather battery heating cause any other issues with an extension cord?

And last cold weather question. I know leaving the car plugged in for days at a time can kill the 12 volt battery. If I was leaving the car for several days or longer without driving it in cold weather, could the cold do any permanent damage assuming the charge got low enough that the battery could no longer heat itself? I know it'd have to warm up to start, but other than that would me leaving town for a week in the harsh winter ruin my battery?
Click to expand...
I’ve been setting the timer to have the car changed 2.5 hours after I’m actually going to leave. The advantage being that the car preheats from the grid, even if it’s not charging. The reality is that if the car is ~75+% it doesn’t charge at all, which is fine for us, if it’s ~50% it charges to 95%+ by the time we unplug. I’m using a 32 amp EVSE and parking in an attached garage. It’s only been cold for a month but so far it’s working for us.
 
WetEV said:
Amazing1 said:
Our "new" Leaf is a 2014 SL. Thank you for your advice. I have also heard that I might consider either a trickle charger on the 12V battery or just disconnect it. Of course doing the latter I probably will have to charge up the 12V separately upon our return. :D
Click to expand...

I've left my 2014 LEAF for 6 weeks with no issues.
Click to expand...

We leave our leaf for 1 to 3 months every year. No issues. I have never lost more than one percent in that 1 to 3 months.
 
We also have a 2016 SV. We have about a 40 kilometre commute so a little shorter than yours. Come fall ours is plugged in as soon as I get home and unplugged in the morning. BUT, the charge timer only allows charging from 1 to 3 in the morning. I use a clipper creek 12 amp 240 volt EVSE so 2 hours is good for about 6 kw. Typically it ents up around 70 to 80 percent charged in the morning.

Because it’s always plugged in I can set the departure timer for when I leave and the car cabin, seats and steering wheel are always warm. As a result very little additional power is used to keep it warm during the morning commute. Afternoon commute is normally warmer (relatively speaking) anyway.
 
I'm afraid of having no range in the morning if it spends all night warming itself unplugged, but without going through it, I really don't know how much power that requires. I
Click to expand...

The battery warmer only uses about 300 watts. It would take several days of around the clock running for the battery warmer to use up a lot of charge. Since it only runs when the pack (not the ambient air) temperature is in the single digits Fahrenheit, that doesn't usually happen.
 

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