eurosteve
Posts: 12
Joined: Mon Jul 24, 2017 10:18 pm

5 months in winter storage

Sat Aug 12, 2017 12:16 am

Hi

I'm in the process of buying a Bolt and I just want to make sure that I won't be damaging the car by leaving it in my unheated garage for 5 months each winter (mid-December to mid-May). I live in upstate New York so it will likely have periods of time below freezing (although not below zero). I see in the manual it says to leave the car unplugged, with only a few bars of charge, and to leave the 12 volt battery on an appropriate charger. Are there any concerns about the car automatically trying to warm up the battery if it gets too cold and in the process depleting the battery? Can the car (battery) handle being left each year for 5 months?

Thanks for any input on this.

eurosteve
Posts: 12
Joined: Mon Jul 24, 2017 10:18 pm

Re: 5 months in winter storage

Sat Aug 12, 2017 12:30 am

Update: I just read the thermal management thread in this "Ask Chevrolet" section. So the question is whether being left in below freezing temps for an indeterminate period (very likely above zero F), damage the battery? Can I assume that if the car is unplugged with only a few bars of charge that the car won't use energy to try to warm the battery?

Would it be better to leave the car plugged in - set to hilltop setting (max 90%) - so the thermal management can warm the battery as needed? Does leaving the car at 90% charge for an extended period damage the battery?

Any insights or advice on this are greatly appreciated.

eurosteve
Posts: 12
Joined: Mon Jul 24, 2017 10:18 pm

Re: 5 months in winter storage

Sun Oct 22, 2017 11:59 am

Ok, so it looks like whoever is monitoring this thread from Chevrolet isn't able to chime in on the topic of winter storage. I did buy the Bolt and I've had it for a few months if that help Chevrolet decide to respond to this thread. After researching as best I can on the internet, I've decided to leave the car at a higher SOC (State of Charge) than the manual suggests, because 2 bars (as recommended in the manual) is only a 10% SOC. I've decided to leave the car at around 30%. What I've read suggests that the battery should always be kept between 30 and 80% if possible and 10% is awfully low. Any help from Chevrolet on this topic of storing the Bolt in cold weather for extended periods is greatly appreciated.

portable
Posts: 30
Joined: Wed Mar 02, 2016 3:08 pm

Re: 5 months in winter storage

Sun Oct 22, 2017 1:10 pm

We can also be reached at (800) 222-1020 and socialmedia@gm.com.

Check us out on FB & TW!
https://facebook.com/ChevroletElectric
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For information on the GM Privacy Statement, please visit http://www.gm.com/privacy.

Note:
The above is copied from a previous "ask Chevrolet" corespondence . The person answering was named "Amber"
It doesn't appear they are taking the time to read the questions on this form anymore. maybe you could reach out through these listed sites and get an answer .

DNAinaGoodWay
Posts: 199
Joined: Fri Sep 23, 2016 11:19 am
Location: Central Massachusetts

Re: 5 months in winter storage

Sun Oct 22, 2017 1:33 pm

I think your plan is reasonable. Unplugged, at 30%, even 40%, should be fine. The battery heater isn’t likely to kick in much if it’s in a garage. It would have to be exposed to long periods of sub-zero temperatures for the battery conditioning to suck up all your kWh. But it’s a real drag that GM can’t give us this information, and we have to compile it ourselves.

Do you have anyone that can check in on it if needed?
Leaf SL 2012-2014
Leaf SV 2014-2017
Bolt LT 2017-
6.72 kW Solar

DucRider
Posts: 537
Joined: Tue Feb 09, 2016 5:25 pm

Re: 5 months in winter storage

Sun Oct 22, 2017 5:35 pm

eurosteve wrote:Ok, so it looks like whoever is monitoring this thread from Chevrolet isn't able to chime in on the topic of winter storage. I did buy the Bolt and I've had it for a few months if that help Chevrolet decide to respond to this thread. After researching as best I can on the internet, I've decided to leave the car at a higher SOC (State of Charge) than the manual suggests, because 2 bars (as recommended in the manual) is only a 10% SOC. I've decided to leave the car at around 30%. What I've read suggests that the battery should always be kept between 30 and 80% if possible and 10% is awfully low. Any help from Chevrolet on this topic of storing the Bolt in cold weather for extended periods is greatly appreciated.

There is a difference between usable and actual pack capacity. The 60 kWh usable on the Bolt does not include the buffer at the bottom and top of the cell when SOC indicates 100%. (0% is NOT completely discharged, nor is 100% completely charged). GM/LG have not released the specs on the cells used, but it is very likely that the actual pack capacity is between 65 and 70 kWh.
I may be in the minority, but I believe that GM and LG know the capabilities, strengths and weaknesses of the battery pack and base their recommendations on those characteristics and not from some "rule of thumb" generalizations garnered from from old data on different battery chemistries.

Chevrolet has given you their recommendations for storing the Bolt in the manual. I doubt very much that a response on a forum would recommend anything different.

It probably won't harm the battery (at least not significantly) to store it at a slightly higher than recommended SOC, so if it makes you feel better, go for it.
Gary

2014 Honda Fit EV - lease ends Jan 2019

eurosteve
Posts: 12
Joined: Mon Jul 24, 2017 10:18 pm

Re: 5 months in winter storage

Mon Oct 23, 2017 11:28 pm

Thanks everyone for your input. I do have someone who can open the door and see what pops up on the screen. That would give me an idea as to what's going on.

I agree that GM almost certainly built in a buffer at both the lower and upper ends of the battery, so that it's impossible to really deplete the battery to 0, and when it's charged to 100%, there is likely a buffer above that. It would be cool if GM would share more information about the battery. But I guess the car is meant to be used by the average Joe and Jane without having to give thought to the inner workings of the battery.

That being said, the reason I'm wanting to double check with GM on what is stated in the manual is that ambient temperature is not addressed in the storage recommendations in the manual. I would like to hear them confirm that it's recommended to store the Bolt at 10% SOC even at 0 degrees F. What I've gleaned over time by reading the various Bolt forums (including this one) is that cold temperatures don't appear to be a problem unless it gets very cold, like below -40 F. But all of this is hearsay since I haven't seen anything about storing in cold temps by GM.

So, I'm going to try to get GM to chime in on this topic, if they will. But it isn't critical. It's just that if Chevy puts itself out there with an "ask Chevrolet" thread, I thought it was reasonable to ... ask them...

Perhaps I'll try to contact Amber...

DucRider
Posts: 537
Joined: Tue Feb 09, 2016 5:25 pm

Re: 5 months in winter storage

Tue Oct 24, 2017 12:43 am

eurosteve wrote:Thanks everyone for your input. I do have someone who can open the door and see what pops up on the screen. That would give me an idea as to what's going on.

I agree that GM almost certainly built in a buffer at both the lower and upper ends of the battery, so that it's impossible to really deplete the battery to 0, and when it's charged to 100%, there is likely a buffer above that. It would be cool if GM would share more information about the battery. But I guess the car is meant to be used by the average Joe and Jane without having to give thought to the inner workings of the battery.

That being said, the reason I'm wanting to double check with GM on what is stated in the manual is that ambient temperature is not addressed in the storage recommendations in the manual. I would like to hear them confirm that it's recommended to store the Bolt at 10% SOC even at 0 degrees F. What I've gleaned over time by reading the various Bolt forums (including this one) is that cold temperatures don't appear to be a problem unless it gets very cold, like below -40 F. But all of this is hearsay since I haven't seen anything about storing in cold temps by GM.

So, I'm going to try to get GM to chime in on this topic, if they will. But it isn't critical. It's just that if Chevy puts itself out there with an "ask Chevrolet" thread, I thought it was reasonable to ... ask them...

Perhaps I'll try to contact Amber...

Above zero won't be a problem at all. Just make sure and disconnect the 12v battery (and place it on a trickle charger) as recommended in the manual. With the 12v disconnected, there will be no battery conditioning (even with the traction battery above the 30% SOC that would normally allow it even if unplugged).

Storing it in that type of cold will not harm the battery. If the situation was reversed and you left it in a garage in someplace like Arizona for the summer it would be a much different story.
Gary

2014 Honda Fit EV - lease ends Jan 2019

LeftieBiker
Posts: 590
Joined: Tue Jan 10, 2017 7:13 am

Re: 5 months in winter storage

Tue Oct 24, 2017 9:30 am

If the 12 volt battery is disconnected from the car, it can be topped off once and then safely left with no trickle charger (actually you'd want a maintainer if anything, which is smarter) because there is no parasitic drain once disconnected.

eurosteve
Posts: 12
Joined: Mon Jul 24, 2017 10:18 pm

Re: 5 months in winter storage

Tue Oct 24, 2017 12:03 pm

DucRider wrote:
eurosteve wrote:Thanks everyone for your input. I do have someone who can open the door and see what pops up on the screen. That would give me an idea as to what's going on.

I agree that GM almost certainly built in a buffer at both the lower and upper ends of the battery, so that it's impossible to really deplete the battery to 0, and when it's charged to 100%, there is likely a buffer above that. It would be cool if GM would share more information about the battery. But I guess the car is meant to be used by the average Joe and Jane without having to give thought to the inner workings of the battery.

That being said, the reason I'm wanting to double check with GM on what is stated in the manual is that ambient temperature is not addressed in the storage recommendations in the manual. I would like to hear them confirm that it's recommended to store the Bolt at 10% SOC even at 0 degrees F. What I've gleaned over time by reading the various Bolt forums (including this one) is that cold temperatures don't appear to be a problem unless it gets very cold, like below -40 F. But all of this is hearsay since I haven't seen anything about storing in cold temps by GM.

So, I'm going to try to get GM to chime in on this topic, if they will. But it isn't critical. It's just that if Chevy puts itself out there with an "ask Chevrolet" thread, I thought it was reasonable to ... ask them...

Perhaps I'll try to contact Amber...

Above zero won't be a problem at all. Just make sure and disconnect the 12v battery (and place it on a trickle charger) as recommended in the manual. With the 12v disconnected, there will be no battery conditioning (even with the traction battery above the 30% SOC that would normally allow it even if unplugged).

Storing it in that type of cold will not harm the battery. If the situation was reversed and you left it in a garage in someplace like Arizona for the summer it would be a much different story.


Thanks again for all of your help with this...

I'm thinking about hooking up the battery tender to the underhood remote positive and negative terminals without disconnecting the battery, as suggested in the manual. If I did this and the SOC was above 30% then battery conditioning might take place if needed (until SOC dropped below 30%). If the battery dropped below SOC of 30% can I assume that battery conditioning would cease?

From Manual: "Remove the black negative (−) cable from the 12-volt battery and attach a trickle charger to the battery terminals or keep the 12-volt battery cables connected and trickle charge from the underhood remote positive (+) and negative (−) terminals. See Jump Starting - North America (page 295 for the location of these terminals)."
Last edited by eurosteve on Tue Oct 24, 2017 1:51 pm, edited 1 time in total.

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