Regenerative braking vs brake pads usage

I just got my Spark EV, drove it home from the dealership and haven't had much time to experiment with it yet. I need to maximize my range to make sure I can get to work and back home without having to stop at a charging station.

I'd like to develop a driving habit to force regenerative braking as much as possible, and minimize the car using the brake pads, but I'm not exactly sure when the the brake pads engage. I would like to know if only the engine braking kicks in for the first ~15mm of stepping on the brakes, then after that the brake pads kicks in to assist, or is it the case where both the regen braking AND brake pads work simultaneously as soon as the brake pedal is stepped on?

If only regen braking is used for the first set amount of brake pedal, then this would be great, as we can start braking over a long distance but only lightly stepping on the brakes to recapture most of the energy back. If anyone has any experience with this, please do share

Congrats on the Spark, and welcome here! I read somewhere (this forum maybe?) that someone wrote that the brake pads engage slightly even when you press the brake pedal a little. But then, if you touch the discs after a drive, you will see how little heat they hold, so there isn't very much energy lost to braking.

If you want to be extreme, you will shift to N to coast, back to D to slow slightly, then L to regen and slow moderately. With experience, you will find how to match your speed and distance so you can but it into L about the right time. Doing that, you can slow almost completely without touching the brake pedal at all. For me, the perfect stopping is to do the above, then touch the brake for the last 100 feet.

Do NOT drive in L all the time if you are trying to maximize your battery distance. That is because the aggressive regen will cause too much slowing, which you then have to overcome by pressing the accelerator again. Remember, when you decelerate and regen, you only get back part of the charge you sent to the battery. So you want to maximize your non-regen coasting.

SteveC5088 said:

If you want to be extreme, you will shift to N to coast, back to D to slow slightly, then L to regen and slow moderately. With experience, you will find how to match your speed and distance so you can but it into L about the right time.

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It's perfectly safe with no negative effects to the car if I shift while it's still moving? I'm switching from a fully manual gas car, so I have no experience with shifting automatic cars. Any time I drive automatic cars, it's just either in reverse or drive, never shifting done to automatics.

Do NOT drive in L all the time if you are trying to maximize your battery distance. That is because the aggressive regen will cause too much slowing, which you then have to overcome by pressing the accelerator again.

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During the one time that I drove it, I did play with the "L" mode very briefly. I believe that if I leave it on "L" all the whole time, I can still compensate the aggressive regen by not completely taking my foot off the gas pedal. If the gas pedal is still every-so-slightly still pressed in, the battery is neither being used nor charging, so it's effectively in neutral (N mode).

In essence, a lot of the braking is done from how much those last few centimeters of the gas pedal is still pressed down, with the max regen being the gas pedal not pressed at all while in "L" mode. I think this is true, but I'll play with it again tomorrow on the 2nd drive.

> It's perfectly safe with no negative effects to the car if I shift while it's still moving?

Yes. I do it all the time. All you are doing is telling the computer controlling the car what you would like it to do. It then throws switches that control how much regen is occurring. During acceleration, changing from D to L or back does changes nothing.

> I believe that if I leave it on "L" all the whole time, I can still compensate the aggressive regen by not completely taking my foot off the gas pedal.

Good luck with that. It's more like adjusting the pedal by a millimeter or two. In theory you can, but I just give up and use the shifter.

When decelerating in L, you will get more regen by pressing the brake pedal lightly. It would be nice if there were a steering wheel paddle to request more regen up to max. ...but you have to buy a Cadillac ELR for that feature currently. I imagine it will come out on more EVs soon.

SteveC5088 is definitely correct when he advises you not to drive in L all the time. I labored under that impression for a while, saw a prior discussion here and thought it made sense to stop - when I did my guess-o-meter scores went way up, as did my reported MPGe in the Onstar app.

Since I stopped driving in L all the time my fully charged range estimate is up to 87 miles. It was hovering around 79 to 83.

Range predictions are vastly affected by your recent driving style.

What I do now is "shift" into L when I'm approaching a stop, or if I'm rolling slowly downhill and I want to store some energy. I also use L in parking lots where the immediate slowing when the foot is lifted from the volt pedal might save a little kid. At very low speeds driving in L gives you instant speed control much like first gear in a car with a transmission.

SteveC5088 is also correct when he says "shifting" into L while moving won't hurt the car. The mechanical connection from the moto to the wheels does not change, but I bet the electrical characteristics of the power going to the motor changes.

I've only got a few days driving, but so far I too seem to get better range using D instead of L. To be honest, I'd prefer if D had zero regen and would just coast until you press the brake pedal (which then would kick regen in). Coasting will always be more efficient that regen, and I'm pretty good at timing it in city driving (I'm coming from a manual transmission car).

I would also like to see something showing you if/when you have transitioned to using the brakes vs. regen. On my wife's Fusion Energi, there's a little percent-o-meter that tells you how well you did with the regen. If you come to a stop and it shows 100%, then you didn't use the brakes at all (until under 5mph). If you had to do a more emergency stop, it will show more like 50%. I try to keep it above 90% for all stops when I'm driving her car. When in D on the Spark, I really have no idea if it is using the brakes or not.