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Quick question about driving in L

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Hello, all, new Volt owner here. (Edit to mention it's a 2011)

When driving in L, and letting off the acceleration to slow the car down- do the brake lights activate?
Having been rear ended in a bad accident in the past, I'm a bit more hypersensitive to the possibility.
Slowing down as much as the Volt can without using the brake pedal has me worried about catching other drivers off guard if there's no indication.
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Hello, all, new Volt owner here.

When driving in L, and letting off the acceleration to slow the car down- do the brake lights activate?
Having been rear ended in a bad accident in the past, I'm a bit more hypersensitive to the possibility.
Slowing down as much as the Volt can without using the brake pedal has me worried about catching other drivers off guard if there's no indication.
No AFAIK the brake light do not go on when decelerating in L (Had my wife follow me to check). Only when brake pedal is actually depress, or in the case of my 2018 the paddle is used.

FYI you did not put model year in your post.
 

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Not on Gen 1. The deceleration supplied by Gen 1 L is below the threshold that requires lamp illumination. Gen 2 has a paddle that does illuminate the brake lights (most of the time) because it does supply enough deceleration, but L still doesn't for the same reason as Gen 1: it's not enough to be required. Only the service brake (the wide pedal) is required to illuminate any time it's applied, regardless of how deceleration is happening.

If you're worried about it, just use the wide pedal. You'll get all the regen you would with L using the wide pedal anyway (because the Volt's braking system is cleverer that Some Others We Could Mention), and you'll already have your foot in the right place in case you suddenly need MORE braking. Like hidden ice, suicidal squirrel, bump that sets off the traction control, etc.
 

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I live where it grows cold and have found "L" to be scary on snowy or icy roads. I feel as if I don't have proper control of the vehicle.

Your tolerance might be higher than mine, but you might want to test it out in a slippery parking lot, so you know how the car reacts in those conditions.
 

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Not on Gen 1. The deceleration supplied by Gen 1 L is below the threshold that requires lamp illumination. Gen 2 has a paddle that does illuminate the brake lights (most of the time) because it does supply enough deceleration, but L still doesn't for the same reason as Gen 1: it's not enough to be required. Only the service brake (the wide pedal) is required to illuminate any time it's applied, regardless of how deceleration is happening.

If you're worried about it, just use the wide pedal. You'll get all the regen you would with L using the wide pedal anyway (because the Volt's braking system is cleverer that Some Others We Could Mention), and you'll already have your foot in the right place in case you suddenly need MORE braking. Like hidden ice, suicidal squirrel, bump that sets off the traction control, etc.
That's odd, because if I'm in L and I completely lift the "Torque Request Pedal" HAHA, my brake lights illuminate. 2016 Gen2.
 

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Having been rear ended in a bad accident in the past, I'm a bit more hypersensitive to the possibility.
If this were an issue it would have been all over this forum by now.

I almost always slow using regen only, i.e. no brake lights. If you are braking enough to be worried about the car being you,
you generally will be on the brake pedal already anyway.

One of the ingenious things Volt engineers tuned into the Volt. Some regen braking, but not too much.
Also, giving you some forward creep when off the gas. Feels like a regular car, not like a battery golf cart.
 

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Yes, you have a GEN 2. As you can see from the first sentence of his reply, "not on Gen 1". The lights also illuminate on ELR.
Not on Gen 1. The deceleration supplied by Gen 1 L is below the threshold that requires lamp illumination. Gen 2 has a paddle that does illuminate the brake lights (most of the time) because it does supply enough deceleration, but L still doesn't for the same reason as Gen 1: it's not enough to be required. Only the service brake (the wide pedal) is required to illuminate any time it's applied, regardless of how deceleration is happening.
As you can see from continued reading of the reply.
 

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Discussion Starter · #10 ·
No AFAIK the brake light do not go on when decelerating in L (Had my wife follow me to check). Only when brake pedal is actually depress, or in the case of my 2018 the paddle is used.

FYI you did not put model year in your post.
Thanks. I thought the model year under username on left would be enough but I've added it to the post as well.
 

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I live where it grows cold and have found "L" to be scary on snowy or icy roads. I feel as if I don't have proper control of the vehicle.

Your tolerance might be higher than mine, but you might want to test it out in a slippery parking lot, so you know how the car reacts in those conditions.
That's funny. I also live where there are icy and snowy roads for at least 5 months per year, and I like driving in "L" because I found that it gives me more control of the car under such trying conditions.
 

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Discussion Starter · #12 ·
I will indeed be driving this in the Wisconsin winter, and will prob stick to D for the brake lights.

I've seen it said that lightly braking (aka riding the brakes) is the same regen anyway if same deceleration rate as L, can anyone confirm? I.e., using brakes on D doesn't just rely on friction braking, regen is still involved (or so the dash graphic suggests)
My goal is just optimizing energy usage, if I don't miss out at all by using D carefully, I won't bother with L

I've also noticed I sometimes forgot I was in L so when throwing into R with 2 clicks I only ended up in N :oops:
 

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@MadVolt : Coasting in Neutral won't hurt the car. It just shuts off all the regen which is a good thing to do every once in a while, so you can use the friction brakes and keep them from rusting. Me? Every drive, the first stop is with the real brakes, to keep the surfaces fresh and everything operating as it should.

When you apply the brake pedal, you get assist unless it's a true panic stop, then the frictions come into play. I will, if I'm slowing from high speed to a stop, for let's say a light that's changed on a highway, shift to L and apply the brakes. The car slows much faster, then.

@uchual : It's strange how different people experience things differently. Being an old guy who's very used to manual transmissions and mechanical everything, when it's icy, I'll often put the Volt into neutral and slow using just the friction brakes. That "automagic" stuff like traction control and anti-skid brakes always feels like it's taking the control of the vehicle away from me, which is the point, I suppose, but I don't like. Yeah, the machine's faster responding than I am, but I'm not so sure it's smarter (though it probably is).
 

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Using L to brake is the same as using D and your foot pedal to brake, except it's completely different.
L has a fixed rate of regeneration created deceleration. That rate varies with the speed (more brake effort when the motor-generator is turning at high speed, diminishing as M-G rotation speed approaches zero) but that amount of effort is the same every time at that M-G rotation speed. You can increase the L brake force by also using the foot pedal, but you can't reduce the L brake effort, except by using the accelerator pedal.
In D your foot pedal can be used to infinitely vary the amount of regeneration and therefore the deceleration rate. You want less slowing force, lightly apply the pedal. More, use more pressure. Oh, and in the Gen1 the foot pedal operates the brake lights during deceleration.

How does the use of L increase regeneration? By causing to to drive at a slower average speed. By slowing at a faster rate when the accelerator pedal is lifted in L, more momentum is converted into recovered electricity than is recovered when the pedal is lifted while in D. That drops the vehicle speed more quickly and reduces the air drag to a lower level more quickly. It's that reduction in air drag that is the consumption reduction.
Driving at the same instantaneous speed whether in D or L will consume the same power and recover the same power.

regarding regen (either D or L) in low traction conditions:
I also shift to neutral when braking on snow or ice. Allowing the independent four channel hydraulic ABS to work to individually control each wheel permits more control under those conditions than an open loop, open differential, 'transmission brake' on two wheels could ever be expected to provide. Starting with hydraulic ABS also eliminates the pucker factor when the controller turns off the regen due to requested brake effort on one (or the other) front tire exceeding the coefficient of friction and slip-skid has started.
 

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regarding regen (either D or L) in low traction conditions:
I also shift to neutral when braking on snow or ice. Allowing the independent four channel hydraulic ABS to work to individually control each wheel permits more control under those conditions than an open loop, open differential, 'transmission brake' on two wheels could ever be expected to provide. Starting with hydraulic ABS also eliminates the pucker factor when the controller turns off the regen due to requested brake effort on one (or the other) front tire exceeding the coefficient of friction and slip-skid has started.
As soon as the traction system detects any wheelslip, it'll turn off regen anyway, and if the wheels DON'T slip, you're just losing whatever power the regen would have provided.

It's really difficult to actually out-think the Volt's engineering for anything except damaged batteries.
 

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Under the low traction conditions there is less braking effort possible before the onset of wheel slip, so the loss of electric power recovery by NOT using regen at all on slippery roads is much less than the regen loss if the roads were grippy.
It's not that the car turns off the regen braking at wheel slip, it's the reaction time needed to respond to that complete loss of any moderate (regen only) braking the car was doing prior to hitting the ice, and applying more pressure/distance to the brake pedal to get hydraulic braking. That fraction of a second can be the difference.
When the roads have ice patches I'll very willingly trade a few Wh of battery charge for immediate ABS brakes on four wheels. My electric rates make the electron recovery savings far less than a replacement bumper cover and a radiator.
Dry pavement? Two wheeled braking by regeneration is frequently more than enough.
 

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I've confirmed my 2017 Volt lights the brake lights in L. Confirmation done at night and watching the reflection off signs behind me when I let off the throttle. It also triggers the brake lights when using the regen paddle. Same confirmation method.
 
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As soon as the traction system detects any wheelslip, it'll turn off regen anyway,
It sure does, and makes it feel like the car is accelerating (its not).

I use to drive in L most of the time, then wife followed me home from a service appointment. She mentioned that it weirded her out that I could go down a steep hill without accelerating and the brake lights not coming on. Now, unless I'm using CC, I just apply light pressure to the service brakes. Lights the brake lights, still get the same regen, and folks behind me feel better.
 

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Hello, all, new Volt owner here. (Edit to mention it's a 2011)

When driving in L, and letting off the acceleration to slow the car down- do the brake lights activate?
Having been rear ended in a bad accident in the past, I'm a bit more hypersensitive to the possibility.
Slowing down as much as the Volt can without using the brake pedal has me worried about catching other drivers off guard if there's no indication.
Not on Gen 1. The deceleration supplied by Gen 1 L is below the threshold that requires lamp illumination. Gen 2 has a paddle that does illuminate the brake lights (most of the time) because it does supply enough deceleration, but L still doesn't for the same reason as Gen 1: it's not enough to be required. Only the service brake (the wide pedal) is required to illuminate any time it's applied, regardless of how deceleration is happening.

If you're worried about it, just use the wide pedal. You'll get all the regen you would with L using the wide pedal anyway (because the Volt's braking system is cleverer that Some Others We Could Mention), and you'll already have your foot in the right place in case you suddenly need MORE braking. Like hidden ice, suicidal squirrel, bump that sets off the traction control, etc.
In my 2019 Volt, L does activate the brake lights. I confirmed this the same way Obermd described in his comment, viz. reflection off street signs at night.
 
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