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First off, let me confess I'm a noob when it comes to how to optimize regenerative braking -- we've had the Bolt for a week, and I've never had any hybrid before... My apologies if these are obvious questions.

My questions are around when/how the Bolt uses regenerative braking. I'm aware of four scenarios that the Bolt regenerates:

1. Simply laying off the accelerator in normal D mode will coast, with a light amount of regen (as seen on the DIC). This feels pretty natural to me, as it decelerates at about the same rate as my old Audi with Quattro (which did not coast all that well).

2. Actually tapping the brake pedal. From what I know, any degree of pressing the brake short of a good, strong stomp (rapid/emergency braking) will just apply increasing degrees of regenerate braking instead. This also feels natural, as if I was just driving a normal car -- only I'm getting power back instead of wearing out the pads.

3. Regen on Demand paddle. I've been actively trying to use this, but I've found its effect to be way too strong. The manual indicates that I can use the paddle while still stepping on the accelerator to control the effect, but I've not mastered that. It also seems a little counter-intuitive to me, to step on the accelerator while also pulling the regen paddle. (And might you be adversely surprised if the regen braking isn't at full efficiency?)

4. One Pedal Driving in L mode: Simply laying off the pedal brakes way too harshly, and I haven't gotten the hang of easing off the accelerator to accurately control the degree of the braking. This might be easier for me to learn than the RoD paddle (which is also hard to use while turning). I do wonder if people get used to driving this way, then have trouble switching back to driving a conventional vehicle.


I'm assuming that the brake pedal, the RoD paddle, and One Pedal are all equally effective at regenerating braking. So if fully holding the RoD paddle, or fully laying off the One Pedal applies maximum regen braking, then there ought to be some throw on the brake pedal which applies maximum regen braking, beyond which it's applying max regen plus some amount of friction brakes? I'm also assuming that the combination of One Pedal at the same time as pulling the RoD paddle isn't any more effective than one method alone.

My expectation then is there's no optimal method of triggering regenerative braking, from an efficiency standpoint -- really just personal preference, as long as I'm not braking so hard that I engage the friction brakes. I'm referring to driving in general -- not stop'n'go or downhill scenarios.

Lastly, when using either RoD or One Pedal to brake, are the brake lights triggered (including the center light)? I assume yes. Do the brake lights remain on after the vehicle comes to a complete stop, such as at a red light, even if you don't end up stepping on the physical brake pedal?

Thanks for reading through this long post... I appreciate any thoughts on this, including "you're waaaaay over thinking this, man!"
 

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Brake lights are automatically lit when deceleration goes above a certain threshold (0.1 Gs, I believe). They do not stay lit after you have come to a compete stop.

I use "L" most of the time, but I have found that in certain situations, I prefer to stay in D because it gives me a better level of control over the car.

You've pretty much nailed how regen braking works in the car. One thing you missed, however, is that if you have fully charged the car to 100%, regen braking is almost non-existant, or severely limited, until the car has consumed dropped a battery bar (5% of capacity). So you are almost entirely relying on the friction brakes. The car has a Hilltop Reserve mode designed to avoid this situation for people who live at the top of a hill. It charges to ~90%. The range hit is minimal and the tradeoff for not having to use the friction brakes is well worth it.
 

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The regen on demand paddle isn't simply an all or nothing thing. The effect of Regen on Demand Paddle can be modulated by the accelerator. It's a little counter intuitive, but still holding the paddle down, you can push down on the accelerator to reduce the rate of regeneration. As you let up on the accelerator, you increase the amount of regeneration.

Basically, holding the paddle down while in D, makes the car act like it's in L.
 

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... The manual indicates that I can use the paddle while still stepping on the accelerator to control the effect, but I've not mastered that. It also seems a little counter-intuitive to me, to step on the accelerator while also pulling the regen paddle.
I employ this method in "L" for my everyday driving.
Once you get the hang of "feathering" the accelerator pedal it's super fun to drive like this.
Just pull the paddle full in without thinking about it and control the breaking by feathering the accelerator.

If you drive like this- the actual brake pads may last the life of the vehicle... :)
 

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We're newbies too, and I had the same effect with laying off the accelerator in L mode at first, braking felt quite harsh. But with a little practice through the neighborhood now I love driving in L mode and my kids say it feels way smoother than driving in D. You'll probably get to love driving that way.
Haven't got the hang of using the paddle/pedal combo yet, guess that's next. A friend of mine with two Volts (both 1st and 2nd gen) always drives in L Sport mode using the paddle. He took our Bolt for a drive and was impressed with the heavy paddle regen compared to his Volt.
 

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Yes, it takes a bit of time to learn to modulate the accelerator for smooth, progressive stops in L mode. But really worth it, IME.

There's been a useful discussion on here on how it's a good idea to put your foot on the brake after coming to regen stop. 1) It illuminates your brake lights. 2) It's insurance against being pushed into an intersection, if rear-ended. 3) It preserves a habit and muscle memory that is useful to access reflexively.

I may be 100% wrong but it sure feels to me that the paddle also increases braking force even when driving in L.

I drive in L all the time on city streets, but find I have a smoother experience on the freeway when in D, using the paddle as needed.
 

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As much as some people might hate the learning curve that comes with, down the road as Chevy refines it and nearly eliminates that, some people might miss the learning curve. It sort of makes the ownership experience fun. Rather than feeling like you pressed a button and it does the rest.
 

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Discussion Starter #8
Thanks for the feedback. I had a revelation today which made driving in L tonight a little easier. Driving with one pedal only is a lot like driving bumper cars. Thinking about it that way did make it easier to remind myself to just ease off on the accelerator to slow down. I haven't gotten the hang of it yet, and I tend to stop short. If you happen to see a Bolt in NJ lurching awkwardly towards lights and stop signs, it's probably me in L mode.

I did notice tonight that I had to step on the brake pedal to keep the rear light illuminated. (It was dark enough that I could see a reflection on the glass.) So it's definitely a good idea to move the foot over to the brake pedal even after coming to a regen stop.
 

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This brings up a question. If you are at a full stop without you foot on the brake, but with the regen paddle depressed are the brake lights on? I haven't checked that one out, but have been assuming that depressing the regen paddle activates the brake lights.
 

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This brings up a question. If you are at a full stop without you foot on the brake, but with the regen paddle depressed are the brake lights on? I haven't checked that one out, but have been assuming that depressing the regen paddle activates the brake lights.


Apparently the L mode standstill position (paddle or not) will not cause rear brake lights to automatically illuminate. A response on the other forum from Chevrolet customer care rep (mentioned also by devbolt in above post #2 ) suggests that rear brake lights auto-illuminate when negative G is more than ~0.1.


I don’t have a G meter*. the other night I tried by myself to gauge rear brake illumination via the rear camera mirror in different L / paddle / L+paddle conditions. I need to do this again with someone else in the rear seat of the vehicle. I don’t think the algorithm is as simple as -0.1G’s. I got a flash (like an F1 car) in some instances.
* there's an ios app for G force, I haven't tried it
 

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One thing you missed, however, is that if you have fully charged the car to 100%, regen braking is almost non-existant, or severely limited, until the car has consumed dropped a battery bar (5% of capacity).
Really good to point that out devbolt.

This was a surprise to learn on the road. We live on the top of a small hill with a speed hump at the base. I had been using the paddle for my first week and getting used to it, trying to get just the right deceleration before the hump. I got a full charge over the weekend, climbed into the car and started down the hill. When i pulled the paddle nothing happened; I tried a few more quick pulls thinking maybe a malfunction or user error. Hit that hump a little hot which rattled the teeth...

I would think the fallback mode would use the friction breaks, but apparently not - probably safety issues with that.
 

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^ my ride home from work is only 22mi...and on secondary roads at 40mph or less.
After a full recharge at work.. I only get full regen when I'm about 2mi away from my house.

I only give it a full charge on Friday's now.
 

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Most of the questions have been well covered but I will add that using the brake pedal does not induce maximum regen. In my experience the only way to get a full 70kw regen (and maximum reduction of speed before involving the friction brakes) is to drive in Low and to use the RoD paddle. Using the brake pedal will only give 50ish kw if I recall so in order to slow the vehicle at a given rate you may be involving the friction brakes while using the brake pedal where you could have done it entirely using regen, recovering more energy and keeping the wheels free of brake dust (one of my main goals!). Of course you at some point you will need more braking than the regen can provide and then you will have to involve the friction brakes, but that threshold is higher if you're in Low combined with RoD paddle.
 

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Most of the questions have been well covered but I will add that using the brake pedal does not induce maximum regen. In my experience the only way to get a full 70kw regen (and maximum reduction of speed before involving the friction brakes) is to drive in Low and to use the RoD paddle. Using the brake pedal will only give 50ish kw if I recall...
Is this confirmed by others? I see no reason why the brake pedal would allow less regen than low mode. How are you measuring the regen rate?
 

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Is this confirmed by others? I see no reason why the brake pedal would allow less regen than low mode. How are you measuring the regen rate?
I can't speak to what others are finding (though I would like to have confirmation either way), but in my tests I'm watching the real-time power consumption / generation indicator on the instrument panel. It takes some speed, above 80kph (45mph?) to hit 70kw, so if you're going to try this get rolling along at about 100 (60mph) then get on the braking systems and slow to about 40 (25mph). In Low with RoD you should see power generation max out at 70kw, then taper off as speeds drop. Doing the same test in Drive with the brake pedal will not achieve the same regen rate no matter how I tried to modulate the decel rate.
 

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Discussion Starter #16
Most of the questions have been well covered but I will add that using the brake pedal does not induce maximum regen. In my experience the only way to get a full 70kw regen (and maximum reduction of speed before involving the friction brakes) is to drive in Low and to use the RoD paddle. Using the brake pedal will only give 50ish kw if I recall so in order to slow the vehicle at a given rate you may be involving the friction brakes while using the brake pedal where you could have done it entirely using regen, recovering more energy and keeping the wheels free of brake dust (one of my main goals!). Of course you at some point you will need more braking than the regen can provide and then you will have to involve the friction brakes, but that threshold is higher if you're in Low combined with RoD paddle.
I like that you'd tried to test it and find out... though do be careful to mind the road when looking at the gauge at the same time ;) I've been happily using the brake pedal plus or the RoD paddle for the past couple of months. Given your findings (L + paddle appears to have higher max regen than brake pedal), maybe my original question shouldn't have been "does brake pedal have the same /maximum/ regen as L mode?" but instead, "is the brake pedal regen as efficient as L mode, when slowing at the same rate?" From a mechanical standpoint, I should think they all regen the same way, because they're going through the same hardware. However, it's possible that the car's software applies the friction brakes on a hard pedal press, before maximum regen effect could occur. In my experience, completely lifting off the accelerator in L, or using the RoD paddle, slows the Bolt down very strongly. Let's call that the maximum, instantaneous application of regen. From a software standpoint, the Bolt might be programmed so that IF you stepped on the brake pedal strongly enough where it would be comparable to maximum regen, AND you also did it instantly (like activating RoD is instantaneous), you might trigger emergency brake assistance = apply the friction brakes sooner?

I personally found that applying full L mode/RoD to slow was actually stronger (more G-force) than I am used to in normal driving. Given that, the "maximum" regen a particular mode allows might be more than I want. So reframing the original question... suppose I'm approaching a red light and I'm slowing at say, 1/3 of the maximum afforded by RoD... shouldn't the brake pedal be equally efficient (regen the same amount) as all other modes?
 

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There is a good point to be emphasized: If the battery is fully charged, and the driver is accustomed to regen-only braking, it will come as a surprise that no braking occurs since the circuitry does not create resistance for the motor-generator. Full battery means no charge resistance! Yipes!

Locomotives use regen braking but they create resistance by running the current thru banks of resistors, when must then be fanned to prevent burning!
 
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