[amps2volts]

I live rural Massachusetts fairly high elevation and temperatures at times can go below 0°F. I can't find much specs on how bolt manages the battery in cold temperatures. And can't find info on battery temperature limits for charging/discharging. I read rapid charging Li-ion in general below 41°F the charge rate has to be reduced. Does bolt do this? Even reduced charging at or below 32°F can cause severe permanent damage to Li-ion batteries. Also read that discharging below 0°F can damage battery because C rating reduced at cold temperatures.

In another post here someone said the bolt has a battery heater? Does anybody know or have info on how the battery heater works in the bolt? Is it a hydronic and heat the batteries liquid cooling lines, how many watts is the heater? Is battery always kept warm when plug in charging and not charging? What about un plugged or driving is it heated?

 

[Thor'sBolt]

I live rural Massachusetts fairly high elevation and temperatures at times can go below 0°F. I can't find much specs on how bolt manages the battery in cold temperatures. And can't find info on battery temperature limits for charging/discharging. I read rapid charging Li-ion in general below 41°F the charge rate has to be reduced. Does bolt do this? Even reduced charging at or below 32°F can cause severe permanent damage to Li-ion batteries. Also read that discharging below 0°F can damage battery because C rating reduced at cold temperatures.

In another post here someone said the bolt has a battery heater? Does anybody know or have info on how the battery heater works in the bolt? Is it a hydronic and heat the batteries liquid cooling lines, how many watts is the heater? Is battery always kept warm when plug in charging and not charging? What about un plugged or driving is it heated?

Hi Amps2volts, did htis get picked up in another thread? I live in MetroBoston and my miles to kW has dropped from a bit over 4 to a little under 3 with the seasonal weather we are having.

Anyone, can you comment on miles per kW in cold weather, and can you pre-warm the car before driving off in the morning and heat up the battery? (Best practices appreciated, as always!)

 

[Jim Fallston Md.]

I have preconditioned twice this week so far and have noticed more than half of the energy used when I checked my energy screen %'s was for battery conditioning. The range you get during colder months will definitely be lower no matter how you use the heat. The upside is if you time your remote start right to 25- 30 minutes before your drive the 20 minute warm up will make the car nice and toasty. Also no need for hilltop reserve as regen is active right away with full battery. And yes DEGREDATION is the wrong word to use for the OP.

 

[RMiller]

Does the battery/motor really need a 20 minute warmup? I don't. Would be disappointed if I had to baby the battery. Not what I expected.

 

[surgeonFWW]

Please explain, once again, for this old man: I thought preconditioning the cabin (plugged in, heating the air with grid electrons instead of battery ones, to save range) was an active event, chosen by you. I thought conditioning the battery (heating or cooling it to increase the ability to get power out) was a passive event, chosen by the car when needed. Are they the same? I have never seen energy spent on “battery conditioning”indicated by my car. Is this because I park in a garage? You CAN “precondition” without being plugged in, right? If I precondition while plugged in and check energy usage as soon as I start the EV, does it then show some spent on “battery conditioning”? Still confused ...

 

[David M O'Rourke]

also - one small nit pick - the battery does not degrade because it's cold - it has a certain amount of power (60 kWh) and when it is too hot or too cold the available battery power is used in different ways to maintain the car's operational status…when outside of ideal temperature ranges for longevity and functionality there will be less power available for the traction motor due to power being redirected to various heating/cooling elements. This will result in the car having less driving range due to external weather conditions.

 

[redpoint5]

No need to be concerned about damaging the battery in cold temps. The car manages all of that by heating/cooling the battery if necessary, and placing certain limits on charge/discharge if temperatures are outside of optimal.

I don't have info about watts of heating ability, but I have heard it said that the car will maintain battery temps as long as it has something like 40% or more charge remaining, even if it isn't plugged in.

Would be interesting if someone had power logs available to show what is pulled from the grid to periodically maintain the battery. Also would be interesting to see what power is pulled when preconditioning the vehicle.

 

[DucRider]

also - one small nit pick - the battery does not degrade because it's cold - it has a certain amount of power (60 kWh) and when it is too hot or too cold the available battery power is used in different ways to maintain the car's operational status…when outside of ideal temperature ranges for longevity and functionality there will be less power available for the traction motor due to power being redirected to various heating/cooling elements. This will result in the car having less driving range due to external weather conditions.

The battery will indeed have less than it's rated capacity as temps drop. But this is not "degrading" in that it is a temporary condition and the capacity will return when it warms.
Battery capacity is usually calculated at 25°C (77°F). At 0°C (32°F) capacity will usually be between 80% & 90% (the specific chemistry in the battery will change it's cold weather performance). In essence, the chemical reaction in the battery is slowed as temps drop.

EV users get the double whammy of lower capacity plus the need to use battery power to provide heat. Other factors are increased rolling resistance and air resistance in cold, damp conditions.

As to cold weather charging, the Bolt has a Battery Management System that monitors things like temperature and adjusts the charging accordingly. If the car is plugged in (or unplugged with a SOC >30%), the battery will have some conditioning (warming in cold weather) provided by the BMS as needed.

 

[Sean Nelson]

Please explain, once again, for this old man: I thought preconditioning the cabin (plugged in, heating the air with grid electrons instead of battery ones, to save range) was an active event, chosen by you. I thought conditioning the battery (heating or cooling it to increase the ability to get power out) was a passive event, chosen by the car when needed. Are they the same?

No they are different. You have it right - "battery conditioning" is not the same as "preconditioning".

 

[Jim Fallston Md.]

No they are different. You have it right - "battery conditioning" is not the same as "preconditioning".

But they do happen at the same time during plugged in preconditioning remote start and the car controls how much battery conditioning is needed.

 

[Sean Nelson]

But they do happen at the same time during plugged in preconditioning remote start and the car controls how much battery conditioning is needed.

They can, but it depends on conditions. There are plenty of times where you may want to precondition the cabin but the battery doesn't need to be conditioned. So you can't treat them as being the same thing.

 

[Poet_663]

Battery estimated range and cold weather

I have read how colder weather affects the driving range you can expect. When I bought my Bolt towards the beginning of September, the temperature during the day was about 75-80 degrees. The top end of estimated driving range (assume consistent driving and routes) at that time was close to 300 miles. The past couple of days have been around freezing in the Seattle area. The top estimated driving range has dropped to around 230 miles. The mileage reduction per charge -- if indeed connected to outside temperature -- is greater than I thought it would be. Not at all a practical issue for me (except for more frequent charging), but seems like external temperature matters a great deal for range.

 

[rgmichel]

Range and miles driven per kWh drops faster with heater compared to A/C

I have now been driving for a few days in the coldest weather I have encountered since I bought my Chevy Bolt, and for the first time I have started using the heater. The first thing I observed was that my range-remaining drops much faster than before. Looking at the car's energy display, its clear that the heater uses more energy than summer air-conditioning. My miles-driven per kWh-used has dropped from about 4 m/kWh to about 3.4 m/kWh. Using a car diagnostic scanner, LELink OBDII, on my last journey the battery temperature started out at 14 C in my garage, and dropped to 12 C over 53 miles of driving with an outside temperature of 4 C. The LElink tells me that no battery heating was done. The charging performance at 32 amps 228 volts remained the same as my experience so far at 0.1 kW per minute of charging consistent with the expected ~ 6 kW charging at 240 volts.

 

[stanwagon]

Question: The SCORE screen has two lines for weather: "Climate Controls" and "Weather" (or is it Temperature). The first is obvious: Use the heater and you are using energy. Fine. But the second seems to indicate that when the temperature is cold one gets a negative score, and range goes down. But I am seeing such a negative score on this line even when there is 0 use of heater and 0 use of battery conditioning. The implication of a negative score here is that low temperatures affects range (regardless of climate control and preconditioning). But people here seem to be saying that is not true. What is the truth here and why does a cool outdoor temp (30 say) give a negative score here?

Yes, the air is denser, but that is certainly a very small effect.

 

[XJ12]

Question: The SCORE screen has two lines for weather: "Climate Controls" and "Weather" (or is it Temperature). The first is obvious: Use the heater and you are using energy. Fine. But the second seems to indicate that when the temperature is cold one gets a negative score, and range goes down. But I am seeing such a negative score on this line even when there is 0 use of heater and 0 use of battery conditioning. The implication of a negative score here is that low temperatures affects range (regardless of climate control and preconditioning). But people here seem to be saying that is not true. What is the truth here and why does a cool outdoor temp (30 say) give a negative score here?

Yes, the air is denser, but that is certainly a very small effect.

I believe the battery works best at 70 F. But only conditions to 40 F if in cold weather so still not at optimal battery temperature. I think the range would suffer more if it tried to heat the battery to the optimal temperature so it's a compromise. Conditioning would not occur if battery is already at 40 F, but during operation, the battery may still stay below the optimal operating temperature. Thus a negative score.

 

[Sean Nelson]

The implication of a negative score here is that low temperatures affects range (regardless of climate control and preconditioning).

Yes, it does. Not nearly as much as terrain or use of the HVAC heater, but a cold battery does have less capacity than a warm one.

When people say "battery temperature doesn't matter" I think what they're really saying is "battery temperature is not very significant compared to running the heater".