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The bolt has antilock brakes, wonderful. Got to test them this week in the ice /snow of South Carolina. Here’s the catch: Regenerative braking does NOT pay attention to locked up wheels. I had it in one pedal mode and eased off the gas when a guy in front of me was slowing and the front wheels locked up. I quickly slapped the shifter into “D” mode the rest of the way home. Just a bit of advice. :)
 

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The bolt has antilock brakes, wonderful. Got to test them this week in the ice /snow of South Carolina. Here’s the catch: Regenerative braking does NOT pay attention to locked up wheels. I had it in one pedal mode and eased off the gas when a guy in front of me was slowing and the front wheels locked up. I quickly slapped the shifter into “D” mode the rest of the way home. Just a bit of advice. :)
I've wondered about the initial regen that occurs when using the brakes in 'D' mode. In 'D' and you start to use the brake, you initially see regen occurring. Is the car just programmed different to prevent slippage in this mode even though it might still be using regen?
 

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I posted this at the winter tire discussion and at one of the other winter threads:

After all the discussion I decided to go out and do a bit more real world testing. Bizzak winter tires, temperatures near 0 F. All the side streets in town are snow/packedsnow with glazed surfaces at some of the intersections. I 90 up to Homestake Pass is mostly clear, a couple shaded spots can be a bit iffiy. The road in to Homestake Lodge, 6 mile RT is solid snowpack. Using L and aggressive regen I was able to lose traction at a glazed intersection. The AntiLock system seems to work fine. I didn't experience any bizarre noises and if glazed enough I was able to make it struggle a bit as well. I found a snowpacked hill with some glazed surfaces and again was only able to lose traction using aggressive regen in L. Normal driving in either L or D was not a problem and he AntiLock brakes did fine. I drove in and out to Homestake Lodge using both D and L and was actually morecomfortable using L, plus I think I was a bit more energy efficient in L. At temperatures closer to freezing I might be more inclined to use D, but at these colder temperatures and a consistent snowpack, L has worked fine.

Bottom Line. Test these possibilities out with your own driving style, comfort and tires and do what you're most comfortable with. If you're not paying close enough attention to road conditions and temperature, it's not going to matter and difficulties may arise.
 

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I've wondered about the initial regen that occurs when using the brakes in 'D' mode. In 'D' and you start to use the brake, you initially see regen occurring. Is the car just programmed different to prevent slippage in this mode even though it might still be using regen?
My experience suggests when you push the brake pedal while in D you get ABS capability even if you're still getting a little regen too. Using ABS gives much better control under very slippery conditions.

More testing needed, unlike Tokodave I've still got the stock tires on. (it's a separate debate as to whether an infrequent winter driver really needs winter tires). I do know that using L mode "one pedal" driving attempting to slow on very slippery surface does not seem to engage ABS & leaves you tobogganing forward aiming at what's directly in front, just like the OP said.
 

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Agree. If you're not dealing with persistent snow covered/icy roads you might be fine with the stock tires and extra care. As I posted above it's probably a good idea to go somewhere with lots of room and get a sense for how L, D and ABS react in various situations.
 

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Agree. If you're not dealing with persistent snow covered/icy roads you might be fine with the stock tires and extra care. As I posted above it's probably a good idea to go somewhere with lots of room and get a sense for how L, D and ABS react in various situations.
This is pretty much a rule for all the cars I owned and all situations. Know your car before you knew your car! 0:)
 

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Got to test them this week in the ice /snow of South Carolina.
It's not arguable the OP felt the regerative braking dangerous. It's also a given those in SC have less experience in ice/snow than those in the northern tier.

It's also not arguable that I disagree completely that regenerative braking is dangerous. I've put a lot of miles recently on glazed snowpacked streets and highways, using L and D and paddles therewith and didn't find any behavior which scared me in the least.

jack vines
 

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Actually reading this along with several others on this thread it all makes sense.

1) Bolt is FWD
2) Whether pedal brakes, D or L, the paddle, the car uses regen braking, snow or not. The amount of regen braking is what is different.
3) Regen Braking is FWD only therefore the car will be applying varying amount of regen braking no matter the decceration to the front wheels only. This means you are not using the rear brakes on the bolt (possible assumption).


People having issues are using stock tires? An assumption based on thread. People not having issues in L mode seem to have snow tires (me included). In L mode the vehicle "brakes" at .1G and that in certain circumstances may be too much for the traction of the stock front tires.

People are stating that during that time the ABS is not going off. I have not in all the snow driving met with that issue, I usually meet the ESC system as i am usually try to power around corners in the snow to see what it does. It my first FWD car and need to get used to the differences. That reminds me to try it with the ECS off :).

Next time I will see whether I can get the ABS to go off but I do remember even using the paddle in L mode (.2G deceleration) and not feeling any slipping. I have Michelin XIce3 snows on the car.

In conclusion ABS or not, in L you are using FWD regen braking only. In D you are using FWD regen with physical braking at a certain point. GM states that the regen difference between D and L are 5% so you will be regen braking mostly in D same as in L before the physical brakes are applied would be a conclusion based on the 5%. They have programmed it to feel different and changed some minor parameters like when the rear physical brakes kick in (that may be the 5%) Therefore I dont see why ABS would not be active during either. I think it just may be the energy efficient tires that have little or no traction in certain winter conditions.

Additional Thought: There is a human aspect to this as well. We are programmed as ICE drivers and our subconsious is programmed to do things for us that we have learned. In a dangerous or need to brake situation in an ICE car one immediately lets off the accelerator and heads for the brake. I found when I first got the car everytime i went to brake I almost went through the widnshield it was so abrupt. I have learned not to do this anymore. But letting off the pedal sharply in L produces an almost instant .1G deceleration and this sudden change may be enough to break the traction on stock tires and given the conditions. seem like the ABS is not working (it my not sound and feel like traditional abs) but they are and that the tires cannot find enough grip.

In conclusion my first thought when I goth the car in november was to get snows. My first set of snows in almost 40 years of driving. I am happy I did for this car.

EDIT:

Here is what the chevy specs say, if anyone can figure it out :)

Power four-wheel disc with ABS; electro-hydraulic; partially regenerative; dynamic rear brake proportioning
 

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- Traction control has nothing to do with slowing or braking. Other than the fact that TC uses the same sensors on the wheels as the ABS function does. TC is all about controlling wheelspin when attempting to accelerate from stop or slow speed.
- My Bolt EV generates up to around 0.35g to 0.40g max deceleration force in L mode with paddle pulled (one pedal driving, no pushing the brake pedal)
- My Bolt has no capability to engage the friction brakes without one's use of the brake pedal (excluding times when it engages the electric parking brake on it's own while stopped on an incline)
- My Bolt has no capability to engage ABS when one pedal driving, that I know of
- With stock low rolling resistance tires, L mode one-pedal deceleration is ineffective in very slippery winter conditions as the front wheels lock rendering the vehicle more or less like a toboggan,

I'm sure that winter tires will help mitigate the outcome contained in last point above. However, for the sake of those readers who are on stock tires there should be no confusion regarding what Bolt can and can't do. Just like the OP said in post #1 -- take the advice.
 

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^ yeah that!

The stock OEM tires are dreadful in snow... probably some of the worst I've ever driven on (been driving since 1979).

If you live in an area where you encounter snow even on a once in a while basis... get real winter tires!
 

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- My Bolt EV generates up to around 0.35g to 0.40g max deceleration force in L mode with paddle pulled (one pedal driving, no pushing the brake pedal)
I'd like to hear more about this. Sounds like you were able to test the deceleration. How did you test it?
 

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I'd like to hear more about this. Sounds like you were able to test the deceleration. How did you test it?
assuming acceleration is constant one calculates the change in velocity (using speedometer) divided by the time measured with a stop watch.

acceleration = (final speed - initial speed) / time

no need for a fancy g meter. Now doing a skid pad test is another matter.
 

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I'd like to hear more about this. Sounds like you were able to test the deceleration. How did you test it?
Using a g-meter app. For example see picture in post #6 of this thread:

http://www.chevybolt.org/forum/82-charging-batteries/20041-charge-infographic-incorrect.html#post250961

Shows g-force attained up to -0.39 over several regen deceleration tests when battery was virtually full.

With battery at or below 88% full g's are more consistently in -0.35 to -0.40 range.
 

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^ yeah that!

The stock OEM tires are dreadful in snow... probably some of the worst I've ever driven on (been driving since 1979).
Have to agree. Stock tires are pretty bad in snow or ice.

Also the Bolt seems to put power to the front wheel with the least traction which doesn’t work well with ice or snow.
 
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