Battery Thermal Management

[LeftieBiker]

All I can tell you is this:
I bought my car in CA. Shipped to Ne. Took 4 days. Salesperson charged the car to full before it was shipped. Went through Colorado and Wyoming in 1st week of January. It was cold. When I received the car when looking at the energy screen it had used "battery condition" for a certain percentage. So to me it must use the "battery conditioning" while unplugged if cold enough.

It would be very helpful if you would look up and post that "certain percentage."

 

[Posatronic]

All I can tell you is this:
I bought my car in CA. Shipped to Ne. Took 4 days. Salesperson charged the car to full before it was shipped. Went through Colorado and Wyoming in 1st week of January. It was cold. When I received the car when looking at the energy screen it had used "battery condition" for a certain percentage. So to me it must use the "battery conditioning" while unplugged if cold enough.

It would be very helpful if you would look up and post that "certain percentage."

I don't know how much and don't think I have a picture. But it was about a 1/4 of the pie. Can't look it up. Unless you know how to retrieve that data. I have a photo of every trip I have made since I got the Bolt but never thought to take a picture of that. I hope to enter my data of driving the bolt someday.

 

[LeftieBiker]

There might be some kind of energy use history - I don't know.

 

[gpsman]

All I can tell you is this:
I bought my car in CA. Shipped to Ne. Took 4 days. Salesperson charged the car to full before it was shipped. Went through Colorado and Wyoming in 1st week of January. It was cold. When I received the car when looking at the energy screen it had used "battery condition" for a certain percentage. So to me it must use the "battery conditioning" while unplugged if cold enough.

This is very interesting.
I'm not sure if I like this feature or not.
Plus you do not know if it actually warmed itself while on the transport or not. ( I doubt it would--- sounds like fire risk to me. ) Most likely some battery conditioning occured duing it's inital test drive. And since the test drive was short, the power used ended up being a large percentage.

Warming the battery while plugged in makes sense.
Warming the battery while NOT plugged in does not make sense. The car does not know if it will sit for 1 hour in the cold or 1 month.

What good is a warm dead battery???

 

[LeftieBiker]

Warming the battery while plugged in makes sense.
Warming the battery while NOT plugged in does not make sense. The car does not know if it will sit for 1 hour in the cold or 1 month.

What good is a warm dead battery???

When combined with a low SOC shutoff, a battery warmer that runs plugged in or unplugged makes a lot of sense. It means that if you have a cold snap for a week and can't plug the car in because it's buried in snow, you don't have to worry. The one in my Leaf is very efficient and has never caused a problem.

 

[BobsBolt]

Hi,

I am new to the forum. I have read a lot of posts, but can't find the one thing I need to know right now.

What is the maximum power that the TMS will use while plugged in during very cold weather. And how much during very hot weather (sounds like it would need to run the AC). And will it need to run this full time or could I just turn it on before use.

I have two parking spots in a condo. One is dry and clean but exposed to outside with a wall plug available. The other is in a basement and is warmer in the winter but very damp. It is right next to a vent so it gets some snow in the winter and no power currently available.

Condo management is sounding very supportive, but the big question is: Do I need 110 or 220? (There is charge station across the street so I don't need it for charging.)

 

[ChevyCustomerCare]

Hi,

I am new to the forum. I have read a lot of posts, but can't find the one thing I need to know right now.

What is the maximum power that the TMS will use while plugged in during very cold weather. And how much during very hot weather (sounds like it would need to run the AC). And will it need to run this full time or could I just turn it on before use.

I have two parking spots in a condo. One is dry and clean but exposed to outside with a wall plug available. The other is in a basement and is warmer in the winter but very damp. It is right next to a vent so it gets some snow in the winter and no power currently available.

Condo management is sounding very supportive, but the big question is: Do I need 110 or 220? (There is charge station across the street so I don't need it for charging.)

Welcome to the forum, BobsBolt! I hope that your Bolt EV experience has been great so far.

Please know that using the travel cord set is sufficient for battery conditioning in extreme conditions. Unfortunately, can't speculate as to what the maximum energy use will be for the TMS, as that would be heavily influenced by outside conditions.

If you do have additional questions/concerns, please feel free to send me a private message!

Amber G.
Chevrolet Customer Care

 

[LeftieBiker]

Geez, it's easy to know this info for the Leaf. The battery warmer comes on when the pack temp (not air temp) is at about 5F, and it uses 300 watts. This info should be readily available for the Bolt.

 

[SparkE]

Geez, it's easy to know this info for the Leaf. The battery warmer comes on when the pack temp (not air temp) is at about 5F, and it uses 300 watts. This info should be readily available for the Bolt.

I have to agree. "If parked outside with a temperature of 10F, the Bolt should use a maximum of 500 W per hour for battery maintenance. In lower temperatures, more energy might be used" or something such.

 

[BobsBolt]

Thanks Amber.

 

[bbock]

GM’s answers are kind of annoying because they don’t really fully answer the questions. For example, they recommend plugging in when the temp is too cold or too warm and they say that energy used for battery conditioning will be available on the display. While that implies to me that the Bolt will condition the battery as needed, even if it is not plugged in. They don’t say how far it’s willing to drain the battery before that stops. I understand they don’t want to say how much juice it will use because first, that’s probably difficult to pre-figure since it takes many factors into account. But I think it’s relevant to have a definite answer if preconditioning happens on battery power when the car is off and if it stops doing that at a certain point before the battery is depleted and how far.

I know ideally GM would like the Bolt to be considered like any other appliance where you just use it the way you want and leave the rest to the people who designed and programmed it. But it’s new tech that clearly concerns people. People need info to ensure they won’t be stranded.

 

[mwk]

Hi, it's been a while since the last entry on this thread so I thought I'd try to get an update. I just leased a Bolt. I am reading the owner's manual and saw this issue of plugging it in when it's cold or hot outside.

My problem is that my office building only has one charging station, which normally wouldn't be an issue because I can reserve it in advance. However, I can't just leave my car plugged in it all day every day when I go to work. I live in Boston, so it will be below freezing many days. If I park the car in my outdoor office parking lot, exposed to the elements on a 25 degree winter day, will I come out to the car at 5pm to a dead car? Or one that doesn't have enough charge left to get me home? The answers from the Chevy rep on this thread were cryptic at best.

Chevy if you are listening, can you answer my question directly? If the car sits in an outdoor parking lot at 25 degrees F for 8 hours, will it be OK to drive? Thanks.

 

[michael]

Hi, it's been a while since the last entry on this thread so I thought I'd try to get an update. I just leased a Bolt. I am reading the owner's manual and saw this issue of plugging it in when it's cold or hot outside.

My problem is that my office building only has one charging station, which normally wouldn't be an issue because I can reserve it in advance. However, I can't just leave my car plugged in it all day every day when I go to work. I live in Boston, so it will be below freezing many days. If I park the car in my outdoor office parking lot, exposed to the elements on a 25 degree winter day, will I come out to the car at 5pm to a dead car? Or one that doesn't have enough charge left to get me home? The answers from the Chevy rep on this thread were cryptic at best.

Chevy if you are listening, can you answer my question directly? If the car sits in an outdoor parking lot at 25 degrees F for 8 hours, will it be OK to drive? Thanks.

Yes, of course it will

When you arrive at work, will you be able to charge up before unplugging? What is your each-way commute?

My rule of thumb is half the rated range, for sure, easy, never worry. So even if you have a 60 mile each way commute and can't charge at work, you are still OK

 

[mwk]

Hi, it's been a while since the last entry on this thread so I thought I'd try to get an update. I just leased a Bolt. I am reading the owner's manual and saw this issue of plugging it in when it's cold or hot outside.

My problem is that my office building only has one charging station, which normally wouldn't be an issue because I can reserve it in advance. However, I can't just leave my car plugged in it all day every day when I go to work. I live in Boston, so it will be below freezing many days. If I park the car in my outdoor office parking lot, exposed to the elements on a 25 degree winter day, will I come out to the car at 5pm to a dead car? Or one that doesn't have enough charge left to get me home? The answers from the Chevy rep on this thread were cryptic at best.

Chevy if you are listening, can you answer my question directly? If the car sits in an outdoor parking lot at 25 degrees F for 8 hours, will it be OK to drive? Thanks.

Yes, of course it will

When you arrive at work, will you be able to charge up before unplugging? What is your each-way commute?

My rule of thumb is half the rated range, for sure, easy, never worry. So even if you have a 60 mile each way commute and can't charge at work, you are still OK

Thanks for that. The only place to plug in is the charging station, so If I've reserved it that day, I'd be fine. I will plan to plug it in to my regular 120v outlet in my driveway at home overnight on cold nights, and my commute each way is under 10 miles, so it sounds like I should be OK then. I was more afraid that the car wouldn't start if the batteries were too cold.

 

[devbolt]

In order for the car to reach the situation where it can’t start, it requires a several day cold soak at extremely low temperatures (well below 0F), and the SOC has dropped to less than 30% so it can’t perform battery conditioning. The car will be fine at 25F for 8 hours. A 10 mile commute, even with you running cabin heat, will leave you with plenty of range when get to work, or back to home.

 

[mwk]

In order for the car to reach the situation where it can’t start, it requires a several day cold soak at extremely low temperatures (well below 0F), and the SOC has dropped to less than 30% so it can’t perform battery conditioning. The car will be fine at 25F for 8 hours. A 10 mile commute, even with you running cabin heat, will leave you with plenty of range when get to work, or back to home.

Perfect. Thanks to both of you for a clear answer. I really love the car so far.

 

[BobsBolt]

OK, so we have had a real cold snap which has given me an opportunity to make some observations. For instance:

- I had it plugged in overnight. In the morning the temp was about -8C. I drove it 6 km and it did not show any use for battery conditioning.

- After being parked for about 2 hrs it still did not show any use for conditioning, but started to use some as soon as I started my next trip. It seemed to continue using it for the entire return trip.

- After 2 more trips (without plugging it in) it was reporting 20% use for conditioning.

So it seems that it was heating the battery while plugged in but not while it was unplugged. Presumably it has different thresholds.

So my conclusion is that keeping it plugged in improves the range because the battery is warmer and it doesn't need to waste battery power warming it up. Also, it seems that a 6 km drive isn't enough to get it up to an optimal temp. Not using the battery for warming would mean less charge cycles so less wear and tear on the battery.

It seems that a cold battery will not produce as much power. On longer drives it is reporting and average of 24kwh/100km, which is almost double the normal use. Some of this is for heat and battery conditioning, but I think some of this might be a miss-reading based on battery conditioning. I say this because 100 km takes my SOC from 88 to about 50 - which would be be 24 kwh at normal temp. If the battery can only hold 40 kwh at -10C (just a guess) then a 40% drop in SOC would only be 16kwh.

We all seem to expect the battery life to be the limiting factor on the vehicle life span, so I want to do what I can to make it's life easier. Anything except stop driving it that is.

 

[mwk]

So here is my feedback, having been through a nasty week of single digit temps. I was off from work last week, and I wasn't driving the car much at all. So, I've left it plugged in to my 120v outlet 24/7 when not in use and just sitting in my driveway. When I got in the car to drive it, the gauge was telling me that 80% of the energy used since the last charge, was for battery conditioning. As soon as I started driving, the driving part and the climate parts took over.

Now, I'm back at work and it's 10 degrees outside. The car will have been sitting in the parking lot, unplugged, all day. I'll be interested to see what the gauge says when I get in the car, and also I hope it starts

As for another observation, at a full charge, the meter is telling me I have, at most, 160 miles range, and at least, 110. Obviously, that's WAY off the advertised range of 238 miles. I do realize it's bitter cold, and batteries don't hold as much energy at these temperatures. However, my point is that I think it's going to be more difficult than people think, to get consumers to consider electric cars, when the range is so wildly affected by the weather. My gasoline car doesn't lose half it's effective range in cold weather. I have a very short commute, and so it isn't as critical for me. BUT, if I had bought the car, thinking it had a 238 mile range, and I needed 100 miles a day for a long commute, and I'm seeing that 110 number at the bottom of the scale, I'd be having some anxiety and regrets about buying the car.

 

[gpsman]

It’s all about HOW you drive, more than the outdoor temperature.

If you start at -20 degrees, get in, and drive till empty, you will go about 200 miles.

If you do many, many short trips, all from a cold start, followed by a cold restart, followed by a cold restart, you may only get about 110 miles - because so much greater percentage is spent on cabin heating and reheating, and battery conditioning and reconditioning.

Long cold weather trips are no problem for this car, since it’s only really cold for the first 10 minutes / miles.

 

[GetOffYourGas]

Long cold weather trips are no problem for this car, since it’s only really cold for the first 10 minutes / miles.

This makes sense to me, but I have no experience with such trips. I always have the worst case - drive 5-10 miles, let the car cold-soak, repeat.

I would love to hear others' direct experience in long-distance cold weather trips. How well does the battery hold its heat? How about the cabin?