[greendave]

Several times now I've arrived at a DCFC in the middle of a trip only to discover that my charging rate is being severely throttled by the car due to 'low' battery temperature. By low temperature I mean 50F, resulting in charging at 24kW with <20% SoC battery, instead of the 50kW the car/charger is capable of. On most of these trips, I've been cruising on the highway at 60-65mph for at least 20 minutes prior to charging, and running the cabin heater. The battery does eventually warm up, but it takes awhile and costs a good bit of time. I wasn't driving, I could plug the car into the wall and 'precondition', but that's not really an option in the middle of a trip. Are there any known methods to force the battery to warm up while driving? Thanks!

P.S. I don't know where the LG/Chevy engineers live that 50F is considered a temperature 'low' enough to warrant limiting the charge rate, but I guess that's a different question.

 

[GetOffYourGas]

I've had this problem too, and am curious at what people come up with.

For example, for Thanksgiving this year I drove about 150 miles to the first charge stop, most of which cruising at 65MPH on the highway with the cabin heat running. Ambient temperatures were in the 20s. When I arrived at the charger (50kW / 120A), it started out at around 20kW and took several minutes to ramp up to about 35kW. It never broke 40kW, although it would have in warmer weather.

P.S. I don't know where the LG/Chevy engineers live that 50F is considered a temperature 'low' enough to warrant limiting the charge rate, but I guess that's a different question.

This decision was likely due to battery chemistry and not climate.

 

[Vertiformed]

Best you can do with the current Bolt software is to precondition (twice) before you set out. Once underway, there's nothing you can do. A software change could fix this, but it's GM we're talking about, not Tesla. Conceivably an aftermarket mod to the heating/cooling assembly and interconnections could change this, but that's probably not going to happen either.

 

[GetOffYourGas]

If there is truly nothing you can do to warm the battery above 50F, that is disappointing. I'm guessing, though, that someone will figure out a trick or two to help warm it up a little closer to 77F (where it supposedly charges at full rate).

 

[Paul Gipe]

Several times now I've arrived at a DCFC in the middle of a trip only to discover that my charging rate is being severely throttled by the car due to 'low' battery temperature. By low temperature I mean 50F, resulting in charging at 24kW with <20% SoC battery, instead of the 50kW the car/charger is capable of. On most of these trips, I've been cruising on the highway at 60-65mph for at least 20 minutes prior to charging, and running the cabin heater. The battery does eventually warm up, but it takes awhile and costs a good bit of time. I wasn't driving, I could plug the car into the wall and 'precondition', but that's not really an option in the middle of a trip. Are there any known methods to force the battery to warm up while driving? Thanks!

P.S. I don't know where the LG/Chevy engineers live that 50F is considered a temperature 'low' enough to warrant limiting the charge rate, but I guess that's a different question.

Saw that you passed through Visalia and charged at the downtown station--not the one on 99.

Paul

 

[GJETSON]

Best you can do with the current Bolt software is to precondition (twice) before you set out. Once underway, there's nothing you can do. A software change could fix this, but it's GM we're talking about, not Tesla. Conceivably an aftermarket mod to the heating/cooling assembly and interconnections could change this, but that's probably not going to happen either.

Nothing other than the current 2+ kW battery heater would be needed. It only needs to stay on longer, or cycle on again after the batteries have had a chance to pull the heat out of the coolant.

 

[ZoomZoom]

I've had this problem too, and am curious at what people come up with.
For example, for Thanksgiving this year I drove about 150 miles to the first charge stop, most of which cruising at 65MPH on the highway with the cabin heat running. Ambient temperatures were in the 20s. When I arrived at the charger (50kW / 120A), it started out at around 20kW and took several minutes to ramp up to about 35kW. It never broke 40kW, although it would have in warmer weather.

This is why I opted to drive an ICE for my Thanksgiving trip this year. The temps were in the 20's. My highway speed limits are higher than yours and I just wanted to get there sooner than later. I hope the technology evolves fast because that will be a game changer.

 

[Sean Graham]

This might be of interest:

Chevy Bolt Battery Cell Arrangement

The cells are arranged in the battery pack like this. There is a cell, a thin piece of aluminum, another cell, a foam pad, another cell, the aluminum, etc. The foam padding isn't really thermally conductive, and is 3mm or about 0.1" uncompressed. However, the pack is under slight tension and...

www.chevybolt.org

 

[Pike Bishop]

Several times now I've arrived at a DCFC in the middle of a trip only to discover that my charging rate is being severely throttled by the car due to 'low' battery temperature. By low temperature I mean 50F, resulting in charging at 24kW with <20% SoC battery, instead of the 50kW the car/charger is capable of. On most of these trips, I've been cruising on the highway at 60-65mph for at least 20 minutes prior to charging, and running the cabin heater. The battery does eventually warm up, but it takes awhile and costs a good bit of time. I wasn't driving, I could plug the car into the wall and 'precondition', but that's not really an option in the middle of a trip. Are there any known methods to force the battery to warm up while driving? Thanks!

P.S. I don't know where the LG/Chevy engineers live that 50F is considered a temperature 'low' enough to warrant limiting the charge rate, but I guess that's a different question.

@Wookhyun Shin recently posted a graph of battery conditioning at a DCFC at -5C that is illustrative. The charging logic is willing to heat at a 2kW rate for 45 minutes after DCFC begins for an input of about 1.5 kWh to the battery. This appears to be sufficient to speed up the charge rate to near 44kW.

Some notes:

• Just driving around at freeway speeds in cold weather does not seem to generate enough internal heating loss to warm up the battery. (Maine resident--Driving I95 at -5 to -10C just does not overcome the thermal losses no matter how long I drive. I will always wait 20-30 minutes for a 125A DCFC to come up to 44+kW
• If the Bolt charging logic is willing to 'waste' 1.5kWh to speed charging after you connect, why, under certain conditions can this be triggered before arriving at a charger?

The last point is critical. It touches upon Tesla vehicles 'network awareness'. When our TM3 is navigating to a supercharger, it begins preconditioning up to 20 minutes prior to reaching the charger. The goal is to minimize charging time and increase mobility. There are other points of 'network awareness': availabllity of chargers, ability to modify maximum charging levels of other Tesla vehicles, all to increase mobility.

In my opinion, network awareness is the killer app. Superchargers are great, but that they work intellingently with the vehicle is the differentiator. This is where mainstream car manufacturers are missing the goal of redefining vehicle mobility. We have worked for 120 years under the vision that the car lives in a 'dumb' network and that fuel was so dangerous that it could not be used at home. Car manufacturers were content to let the oil companies develop the 'dumb' network. The goal was to sell cars into a captive fueling market. The result was a gas station on every corner.

The situation is very different now. The technology is already on board (OnStar has its own GPS). Charging providers can provide real time status. It's just lacking vision, a plan, and collaboration. (I don't think the My Ch
evy App is even close...)

 

[bro1999]

Best you can do with the current Bolt software is to precondition (twice) before you set out. Once underway, there's nothing you can do. A software change could fix this, but it's GM we're talking about, not Tesla. Conceivably an aftermarket mod to the heating/cooling assembly and interconnections could change this, but that's probably not going to happen either.

I tried telling a GM engineer that a "heat battery while driving" feature would be nice, as we could mitigate getting charge rates neutered by cold battery temps on demand. He didn't seem to get it though. But supposedly the 2020 Bolts have vastly improved cold weather fast charging.

 

[greendave]

Thanks for all the comments.

Best you can do with the current Bolt software is to precondition (twice) before you set out. Once underway, there's nothing you can do. A software change could fix this, but it's GM we're talking about, not Tesla. Conceivably an aftermarket mod to the heating/cooling assembly and interconnections could change this, but that's probably not going to happen either.

That's what I figured, but thanks for the confirmation. I'm not sure how well the preconditioning would have worked in my case - I was driving for almost 3 hours straight before charging (mostly downhill), but it should cover most usages.

This decision was likely due to battery chemistry and not climate.

Absolutely. The battery chemistry is what it is - the point is that they didn't come up with much of a mitigation/workaround - which makes me think they didn't see it a significant limitation.

• Just driving around at freeway speeds in cold weather does not seem to generate enough internal heating loss to warm up the battery. (Maine resident--Driving I95 at -5 to -10C just does not overcome the thermal losses no matter how long I drive. I will always wait 20-30 minutes for a 125A DCFC to come up to 44+kW

That's quite annoying. I was driving in 0-5C and it did warm up, albeit very slowly.

The situation is very different now. The technology is already on board (OnStar has its own GPS). Charging providers can provide real time status. It's just lacking vision, a plan, and collaboration. (I don't think the My Chevy App is even close...)

A very good point. None of this is rocket science. It just requires seeing the big picture. It's a longshot but perhaps ABRP could grow in that direction (or EA or EvGo's own apps - but those seem to be afterthoughts).

Saw that you passed through Visalia and charged at the downtown station--not the one on 99.

Yes, we went to Sequoia for the weekend (from San Jose). I liked the Visalia downtown charger much better than the others (Madera EA and Gilroy EA - getting tired of visiting Walmarts). It's a nice location for a 30-45 minute break - we walked around but there were plenty of restaurants/shops in the area.

 

[John Mc]

How do you manually start a precondition in a 2019 Bolt when charging at home?

 

[SparkE]

With the keyfob. It is described in the manual.

 

[RichardC]

My two cents is that DCFC for the Bolt was a secondary consideration and the engineers figured most people would be charging at home. This is born out by the fact that DCFC was a $750 option. Face it, the Bolt is a city/commuter car with enough range to make it a tease to take it on long trips. As soon as you folks understand this the anxiety melts away. Most of us this learned this the hard way after we bought the car, but hey, it is new tech and the learning curve is steep. Still, GM did a pretty decent job for their first long range main stream EV.
Save up your money for a Model Y, that should be killer ( if they can stop water from leaking in various places, provide better service and parts).

 

[The Other Tom]

How do you manually start a precondition in a 2019 Bolt when charging at home?

I'm pretty sure battery heating starts automatically if you have the car plugged in. The car doesn't need to be running. If you want to start the car remotely so that the cabin will be heated (or cooled), then you can do that from the key fob as has been previously posted.
Edit: From Eric Way aka News Coulomb on Facebook:
"Last time we had these overnight temperatures, I left my Bolt EV unplugged, and the battery's internal temperature dropped to 31° F. By leaving it plugged it (the car was off), it appears that the Bolt EV attempts to maintain an internal pack temperature at over 50° F."

 

[John Mc]

I'm pretty sure battery heating starts automatically if you have the car plugged in. The car doesn't need to be running. If you want to start the car remotely so that the cabin will be heated (or cooled), then you can do that from the key fob as has been previously posted.
Edit: From Eric Way aka News Coulomb on Facebook:
"Last time we had these overnight temperatures, I left my Bolt EV unplugged, and the battery's internal temperature dropped to 31° F. By leaving it plugged it (the car was off), it appears that the Bolt EV attempts to maintain an internal pack temperature at over 50° F."

Thanks. That helps. That's what I thought. I was confused by the post which stated "Best you can do with the current Bolt software is to precondition (twice) before you set out." I was not aware of a way to trigger the preconditioning. I just leave our Bolt plugged in overnight in cold weather.

I thought I remembered seeing that no battery conditioning takes place when plugged in to a 120V level 1 charger, but I can't find that reference right now. I wonder if it works if you use one of the 240V adaptors with the included 120V EVSE. Almost all of our charging is on our Level 2 charger at home, but it would be interesting to know for when we are on the road.

 

[GetOffYourGas]

I thought I remembered seeing that no battery conditioning takes place when plugged in to a 120V level 1 charger, but I can't find that reference right now.

I've read conflicting things on this subject. The 120V EVSE (1440W) cannot supply enough power to condition the battery (up to 2500W, I believe). BUT, the car could simply pull the deficit out of the battery itself. It's not clear to me whether it does so, and nor have I tried it myself.

 

[tomw]

@Wookhyun Shin recently posted a graph of battery conditioning at a DCFC at -5C that is illustrative. The charging logic is willing to heat at a 2kW rate for 45 minutes after DCFC begins for an input of about 1.5 kWh to the battery. This appears to be sufficient to speed up the charge rate to near 44kW.

Some notes:

• Just driving around at freeway speeds in cold weather does not seem to generate enough internal heating loss to warm up the battery. (Maine resident--Driving I95 at -5 to -10C just does not overcome the thermal losses no matter how long I drive. I will always wait 20-30 minutes for a 125A DCFC to come up to 44+kW
• If the Bolt charging logic is willing to 'waste' 1.5kWh to speed charging after you connect, why, under certain conditions can this be triggered before arriving at a charger?

The last point is critical. It touches upon Tesla vehicles 'network awareness'. When our TM3 is navigating to a supercharger, it begins preconditioning up to 20 minutes prior to reaching the charger. The goal is to minimize charging time and increase mobility. There are other points of 'network awareness': availabllity of chargers, ability to modify maximum charging levels of other Tesla vehicles, all to increase mobility.

In my opinion, network awareness is the killer app. Superchargers are great, but that they work intellingently with the vehicle is the differentiator. This is where mainstream car manufacturers are missing the goal of redefining vehicle mobility. We have worked for 120 years under the vision that the car lives in a 'dumb' network and that fuel was so dangerous that it could not be used at home. Car manufacturers were content to let the oil companies develop the 'dumb' network. The goal was to sell cars into a captive fueling market. The result was a gas station on every corner.

The situation is very different now. The technology is already on board (OnStar has its own GPS). Charging providers can provide real time status. It's just lacking vision, a plan, and collaboration. (I don't think the My Ch
evy App is even close...)

I think it depends greatly on the engineers and management. Tesla has a lot of young PhD engineers who did work in grad school closely related to what they do at Tesla. This gives them both depth and breadth of relevant knowledge, and they have no pre-conceptions of "this is the way we've always done it". They are eager to invent new things, new ways. Many of the engineers at the legacy car manufacturers are older and more experienced. That has some advantages as far as not making mistakes similar to those made in the past, but it can also make them less enthusiastic about pursuing something new and different since they have seen many failures in the past - and seen careers suffer for it.

It also depends on management - what they reward. Do they only reward those who they perceive to have never made mistakes? (note the qualifier "perceive") Do they reward those who take risks that may pay off big, but also have significant risk of failure? I suspect Musk is more likely to do the latter, encouraging people to innovate and try new things, just taking failures in stride, learning and moving on - and rewarding people who took on risky projects and failed, but who he thinks did well considering the circumstances.

 

[Sean Nelson]

I think it depends greatly on the engineers and management. Tesla has a lot of young PhD engineers who did work in grad school closely related to what they do at Tesla. This gives them both depth and breadth of relevant knowledge, and they have no pre-conceptions of "this is the way we've always done it".

To be fair, there isn't much of an "this is the way we've always done it" at any of the auto manufacturers when it comes to battery thermal management. Especially at Nissan...

 

[Vertiformed]

You precondition with the “remote start” feature. Chevy doesn't tend to use the term itself, so you won't find it in the manual. I think the term originated with other EVs.

You can also just go out and turn on the car manually with it plugged in (and just don't drive away).

One plugged in and switched off, the car will keep the battery in a sensible range, but when powered up (either remote-start or just turning it on while plugged in), it'll warm it further.

That's my understanding, anyway.