Thanks for your testing. Here in far northern Maine I've seen "Propulsion Power Reduced" once when the outdoor temp was around -10F and my Bolt EV wasn't on my home L2. It's been -23F but with the L2 connected overnight I didn't get that warning.
Right, keeping the car plugged in with a steady stream of juice is usually a safe bet. Interesting you got the propulsion warning in that scenario... I've only ever seen it when running at a low state of charge, but I guess the battery heater ramping up to combat the cold when unplugged could push it into that territory. We simply don't get that low here in our standard winter conditions to test it properly. Thanks for the insight!
This is helpful. My first charge with my bolt was 100 miles away from the dealer, about 2 degrees F. I got 32kwh from a 50kwh DCFC. I was bummed then but I guess I should have been happy for what I got!
Yep, that sounds pretty good for winter, especially on a 50kW station! Do you have a previous model year Bolt or a 2020 though? The improvements to the 2020's winter charging seem to make a 30kW start up about standard, from what I've seen so far.
Awesome - I kept complaining about my 20kw start … I knew it was the cold weather but it’s only 50f with me it shouldn’t been this low - I also notice decrease in charge speeds with new battery ( winter time ) summer it’s amazing . Except when it goes over 100f then same thing as winter 🤦🏻♂️
GM has always been extremely cautious with the Bolt's fast charging curve, especially below 40F. Even above that can see some lower power charge sessions, though 20kW is very low, even for freezing weather. That said, the charge curve does seem to be different on newer models and replacement battery packs, so it could be significantly different now as the video is several years old. Thanks for watching though!
Recharged our Model 3 at a hotel supercharger on a very cold night immediately after driving several hours. Charged fine. I was shocked at how slow it was on a cold morning. Although it picked up after about 45 to and hour minutes
You need a stretch of road where you can go pedal to the medal then full regen 10 times back to back. Driving 70 mph is not going to use many kW. You want 150 kw acceleration and 60 kw deceleration until the regen limit indicator goes away. The battery heater is 2kw. And that is what will run off the charger until it heats up. You need to get more than 2kw of waste heat from current in the battery. If you can’t, you might as well go plug in to a lvl2 charger until the battery heater warms up the battery and then you can move to the fast charger. Running the heater is counterproductive during regen because it lets you burn those kw instead of forcing it back into the battery. It is interesting that it allowed brief 50 kw regen but wouldn’t accept 30 kw charge.
Right, I saw the actual Bjorn videos you referenced after these sessions... so his stop-start repetition is definitely interesting but would be hard to replicate at this location with the busy suburban roads. At night, maybe possible. I was surprised at the second session (still images only in the hood), however, which I thought would be enough driving to hit higher start rates. Although the tests have been interesting, I think the takeaway for regular drivers in this position is to stick to home/public L2 charging when it's near freezing or find a free/flat fee DCFC so that the cost isn't exorbitant. I don't see many wanting to bunny hop down the road in winter conditions to make this happen!
Ste, if you do another test where you have a short distance between off ramps and no traffic, such that you can accelerate up to max legal speed then regen until the off ramp, then loop around and get back on in the opposite direction and repeat until the regen limit is completely gone, you might be able to hear the battery faster that just going straight to the charger. Some places have dedicated U-turn lanes to get back on the highway. If you don’t, then possibly traffic or traffic lights would ruin this method. The experiment needs to address two situations, one is that you don’t have time to wait for the battery heater to warm the battery and you can do it faster by driving like you stole the car, and the other is paying $0.35/minute to get 15kw for 30 minutes. The first one is straight forward but the second one needs to account for how many kWh you wasted trying to warm up the battery. If you wasted a net (after regen) of 10 kw, then can you recoup that with faster charging? Of course if you are at a charger that charges per kWh this is not needed. By far the best thing they can do is give the driver the information about what speed their battery can charge at based on its current temperature, and allow the driver to manually turn on battery heater when enroute to a DCFC. I think as charging infrastructure gets more reliable they can do this, but with spotty coverage, it would allow drivers to waste energy to get to a charger which is out of service. But there is no excuse for Tesla to not do it with their supercharger network. The car should even be able to automatically turn on battery heat as soon as you select a supercharger as your destination. But the programmers are too busy making fart apps. Lol
Thanks! It's actually a GoPro mounted in the spot where a dashcam would sit. No use for extended use or security but it does take some great road trip footage :-)
When you were on the L2 charger you could have started 2 sessions of preconditioning which will give 40 minutes of battery warming @2.5KW from the J1772 (assuming the car HVAC is already at the set point). When you transfer to the rapid charger you will get a higher rate when connecting to a fast charger Driving below freezing, the battery is generally around 4c/38f. The car ramps up the charge rate as the temperature rises to 20c/68f for a rate of 45KW/h. (charge rate varies with temperature as active battery management does its magic and pampers the battery).
Belated thanks for your reply, Don. I've been looking at OBD readings as the temperatures start to drop here and will be working your suggestions into a winter 2019/'20 test, if I can find the right location to do so.
Thanks for your testing. Here in far northern Maine I've seen "Propulsion Power Reduced" once when the outdoor temp was around -10F and my Bolt EV wasn't on my home L2. It's been -23F but with the L2 connected overnight I didn't get that warning.
Right, keeping the car plugged in with a steady stream of juice is usually a safe bet. Interesting you got the propulsion warning in that scenario... I've only ever seen it when running at a low state of charge, but I guess the battery heater ramping up to combat the cold when unplugged could push it into that territory. We simply don't get that low here in our standard winter conditions to test it properly. Thanks for the insight!
This is helpful.
My first charge with my bolt was 100 miles away from the dealer, about 2 degrees F. I got 32kwh from a 50kwh DCFC. I was bummed then but I guess I should have been happy for what I got!
Yep, that sounds pretty good for winter, especially on a 50kW station! Do you have a previous model year Bolt or a 2020 though? The improvements to the 2020's winter charging seem to make a 30kW start up about standard, from what I've seen so far.
@@plugandplayEV I've got a 2020. Good to know that may be the difference. Being in Minnesota it's below freezing a big part of the year.
Awesome - I kept complaining about my 20kw start … I knew it was the cold weather but it’s only 50f with me it shouldn’t been this low - I also notice decrease in charge speeds with new battery ( winter time ) summer it’s amazing . Except when it goes over 100f then same thing as winter 🤦🏻♂️
GM has always been extremely cautious with the Bolt's fast charging curve, especially below 40F. Even above that can see some lower power charge sessions, though 20kW is very low, even for freezing weather. That said, the charge curve does seem to be different on newer models and replacement battery packs, so it could be significantly different now as the video is several years old. Thanks for watching though!
Recharged our Model 3 at a hotel supercharger on a very cold night immediately after driving several hours. Charged fine. I was shocked at how slow it was on a cold morning. Although it picked up after about 45 to and hour minutes
Thanks for sharing (experience and car ;-)
You need a stretch of road where you can go pedal to the medal then full regen 10 times back to back. Driving 70 mph is not going to use many kW. You want 150 kw acceleration and 60 kw deceleration until the regen limit indicator goes away.
The battery heater is 2kw. And that is what will run off the charger until it heats up. You need to get more than 2kw of waste heat from current in the battery. If you can’t, you might as well go plug in to a lvl2 charger until the battery heater warms up the battery and then you can move to the fast charger.
Running the heater is counterproductive during regen because it lets you burn those kw instead of forcing it back into the battery.
It is interesting that it allowed brief 50 kw regen but wouldn’t accept 30 kw charge.
Right, I saw the actual Bjorn videos you referenced after these sessions... so his stop-start repetition is definitely interesting but would be hard to replicate at this location with the busy suburban roads. At night, maybe possible.
I was surprised at the second session (still images only in the hood), however, which I thought would be enough driving to hit higher start rates. Although the tests have been interesting, I think the takeaway for regular drivers in this position is to stick to home/public L2 charging when it's near freezing or find a free/flat fee DCFC so that the cost isn't exorbitant. I don't see many wanting to bunny hop down the road in winter conditions to make this happen!
Ste, if you do another test where you have a short distance between off ramps and no traffic, such that you can accelerate up to max legal speed then regen until the off ramp, then loop around and get back on in the opposite direction and repeat until the regen limit is completely gone, you might be able to hear the battery faster that just going straight to the charger.
Some places have dedicated U-turn lanes to get back on the highway. If you don’t, then possibly traffic or traffic lights would ruin this method.
The experiment needs to address two situations, one is that you don’t have time to wait for the battery heater to warm the battery and you can do it faster by driving like you stole the car, and the other is paying $0.35/minute to get 15kw for 30 minutes.
The first one is straight forward but the second one needs to account for how many kWh you wasted trying to warm up the battery. If you wasted a net (after regen) of 10 kw, then can you recoup that with faster charging? Of course if you are at a charger that charges per kWh this is not needed.
By far the best thing they can do is give the driver the information about what speed their battery can charge at based on its current temperature, and allow the driver to manually turn on battery heater when enroute to a DCFC. I think as charging infrastructure gets more reliable they can do this, but with spotty coverage, it would allow drivers to waste energy to get to a charger which is out of service.
But there is no excuse for Tesla to not do it with their supercharger network. The car should even be able to automatically turn on battery heat as soon as you select a supercharger as your destination. But the programmers are too busy making fart apps. Lol
What kind of dashcam did you use? It puts out a great wide picture!
Thanks! It's actually a GoPro mounted in the spot where a dashcam would sit. No use for extended use or security but it does take some great road trip footage :-)
How do you know what exact percent your battery is at?
Either the MyChevy app can tell you on the 'Vehicle Status' tab or you can use an OBD app like Torque Pro for a more exact percentage.
When you were on the L2 charger you could have started 2 sessions of preconditioning which will give 40 minutes of battery warming @2.5KW from the J1772 (assuming the car HVAC is already at the set point).
When you transfer to the rapid charger you will get a higher rate when connecting to a fast charger
Driving below freezing, the battery is generally around 4c/38f. The car ramps up the charge rate as the temperature rises to 20c/68f for a rate of 45KW/h. (charge rate varies with temperature as active battery management does its magic and pampers the battery).
Belated thanks for your reply, Don. I've been looking at OBD readings as the temperatures start to drop here and will be working your suggestions into a winter 2019/'20 test, if I can find the right location to do so.