[jefro]

Best to coast to stop if you are hypermiling. Bolt doesn't make it easy to coast like the BMW i3 does. It has a detent on gas pedal to let you coast.
EV's are not perpetual motion machines. You may only get 25% of the acceleration power back. That is what my tests show generally. I've tried different velocities and lower speeds should have returned more but even regen on very low current doesn't change a lot from full regen in terms of efficiency. .

 

[liresong]

Really good drivers maybe are able to coast down in Neutral from 60MPH to 15MPH, then apply brakes for a full stop. Doesn’t sound too good, but energy saved is the square of the speed. If you can stay off your brakes till 15MPH, you are saving 93+% of driver “inefficient” braking energy from 60MPH. As for me, I’m happy when I can coast in Neutral down to 20MPH before having to brake to a stop.
However, we’re not talking about a more important aspect & that is battery stressing. Drawing energy OUT of the battery while at 60MPH in L or D, AND then adding that same energy BACK INTO the battery while slowing & regenerating is a terrible thing to do. If the battery is to last 300,000+ miles, extracting energy from the battery while in D or L, AND putting energy back into the battery while regenerating is the thing…..NOT TO DO.
Who would have thought that doing nothing while coasting in Neutral could be so doubly good for the battery!

 

[lynoise]

Best to coast to stop if you are hypermiling.

This is key to this discussion.

If we are simply comparing coasting to a stop vs using one pedal driving to slow to a stop, regenning will be more effecient.
The distance traveled is the same in both cases. In one case you used 0kw of energy, n the other you put "some" energy back into the battery.
-But-
if you are hypermilling that is a totally different animal. When hypermilling you are trying to get the most distance out of 0 energy as possible. Regen will limit the amount of distance you will "coast". Hypermilling will be actuall coasting a lot more than you would be regenning over an entire trip which would likely be much more effecient than regenning all the time and then having to accelerate again (usin gmore power than you regenned).

So if you are actually hypermiling then coasting is more efficient.
If we are talking about general stop and go regen is better (arguable as to how much, but definitely more efficient)

 

[jefro]

Not easy to hypermile in my town.

 

[liresong]

Not easy to hypermile in my town.

Same here. But, I love to travel the slower back roads with a bit less traffic trying to push you faster on the road.

 

[Packard V8]

However, we’re not talking about a more important aspect & that is battery stressing. Drawing energy OUT of the battery while at 60MPH in L or D, AND then adding that same energy BACK INTO the battery while slowing & regenerating is a terrible thing to do. If the battery is to last 300,000+ miles, extracting energy from the battery while in D or L, AND putting energy back into the battery while regenerating is the thing…..NOT TO DO.
Who would have thought that doing nothing while coasting in Neutral could be so doubly good for the battery!

Yes, No, Maybe. There is not yet sufficient data to prove coasting would reduce battery degradation over time. You say it definitely would. Another might say with equal confidence, "If coasting would extend the life of the battery and reduce GMs warranty liability, they would have built in a coasting mode."

jack vines

 

[VoltoBolt]

Sure, coasting's better, but it will be a minimal difference. And it does also technically save on battery degradation, as you stop pulling power earler, and put less back in. Personally, I'll frequently get off the throttle early (just shift into N, unlike a gas engine, it won't rev the balls out of the motor), coast for a while, and then then come back into D or L to stop. That way I avoid the annoying portion of coasting where you travel at low speed, but also don't use the friction brakes.
Takes a time or two to get the feel for how far from a stop sign you do it at a given speed, but not hard. Am I saving much in the way of range? No.

At what speed have you actually shifted from N back to D or are these merely hypothetical musing?

 

[Sean Nelson]

Regen is not 100% efficient, so if you're using it when not really necessary then you're wasting energy. For example, if you're approaching a red light on a slight upgrade, better to let the energy you've already expended in getting the car up to speed carry the car up to the light while being slowed by gravity. If you power up to the light and then use regen to stop, you're expending extra energy to go up the grade and you're not recouping it all by stopping with regen.

That having been said, when you actually require braking force (i.e, downhill grades, unexpected stops) then having regen to recover most of your momentum into energy is way better than not having it.

Note that you get regen even while using the brake pedal in D mode, so you don't have to be a one-pedal driver to benefit.

Note also that you don't need to go from L into N to coast - you just need to apply the right amount of pedal pressure to maintain roughly 0 on the power meter.

 

[BoltEUV]

I drive on rural roads with very little traffic. When I see a train about to cross and there's no one behind me I just let the car coast from a long distance. There's no point rushing to get to a railroad crossing and then wait 5 minutes. I do love one pedal driving in the Bolt more than in the Volt. The regen in the Volt isn't aggressive enough. I end up using the regen paddle most of the time. But the Bolt's regen is strong and somewhat predictable. I can feather the accelerator pedal or use the regen paddle as needed.

 

[404 Not Found]

Not easy to hypermile in my town.

Yes, coasting is good but hypermiling can stir up a lot of anger around you. In such situations it's helpful that the Bolt can stay at fairly high speed down an exit ramp and do strong regen at the bottom. This saves your brakes and aggravates no one. I would use coasting or regen depending on the traffic around me. Don't want this to happen.

 

[Packard V8]

Yes, coasting is good but hypermiling can stir up a lot of anger around you. In such situations it's helpful that the Bolt can stay at fairly high speed down an exit ramp and do strong regen at the bottom. This saves your brakes and aggravates no one. I would use coasting or regen depending on the traffic around me.

For true. I'm on both sides of this debate. I'm on an urban arterial, two lanes in my direction and up ahead the traffic light goes red. I slow immediately; the car behind me changes lanes, passes and continues at speed up to the stopped traffic and brakes hard. I ease up beside him/her/they as the light changes and we pull away at the same time. I will never understand what he was thinking. My wife says, "Honey, he wasn't thinking at all; most drivers aren't, you know."

jack vines

 

[Martin D]

Before I would even dream of putting my transmission in neutral while the car is traveling at speed, I would make completely sure that everything cooling wise and lubrication wise is in full operation, and specially pressurized lubrication. If anything shuts off from being in neutral it is going to be a very expensive lesson. And the motor always turns. There are permanent magnets that are trying to generate some energy without back feeding and power into the stator coils to max the regen.

I just don’t know enough about the design of the bolt propulsion unit, and the last people I am going to listen to about it are people speculating on an Internet forum. I don’t want anyone to take personal offense, but I don’t trust a single thing I read about this type of discussion.

The minuscule amount of generation that is going to happen due to rotating magnets is something that neutral on the transmission shifter is not going to change. I think the only reason for the neutral is for a car wash conveyor to pull the car through.

Good luck hypermiling for ant shite return. I don’t chase rolling nickels because there is much more meaningful ways to save. Like combining trips. I challenge anyone to get a lower energy use than performing two trips in one occasion by planning ahead.

But don’t let me change the hypernerding discussion if it’s what blows up anyone’s skirt. YMMV

 

[Dimitrij]

I do not think there is a measurable difference in the efficiency of regeneration between one-pedal deceleration and coasting to stop. At the same time if get green before you completely stopped, you will use less energy accelerating back to the travel speed. So, all things considered, coasting (as a habit) is probably going to be somewhat more efficient. Regardless, I always use the one-pedal drive function, as IMO it's safer.

A corollary question perhaps could be, What's the max regen capacity of the Bolt - would it be the same 55 kW as [GM says] you'd get at an adequately powered L3? I forgot what was the highest level was that I observed.

 

[Martin D]

I do not think there is a measurable difference in the efficiency of regeneration between one-pedal deceleration and coasting to stop. At the same time if get green before you completely stopped, you will use less energy accelerating back to the travel speed. So, all things considered, coasting (as a habit) is probably going to be somewhat more efficient. Regardless, I always use the one-pedal drive function, as IMO it's safer.

A corollary question perhaps could be, What's the max regen capacity of the Bolt - would it be the same 55 kW as [GM says] you'd get at an adequately powered L3? I forgot what was the highest level was that I observed.

I have heard it’s 70kW. I have never looked to see what the kW meter can max at, but I have seen more than 60.

What I have noticed is what the CC does when it gets put on resume after coming to a stop. I will hit resume at about 20 mph, and the CC will get up into the high 60’s. And that is almost to the point where the big ring color starts to change to yellow. The CC will use right below the threshold for inefficient acceleration.

Using friction brakes will also turn the big ring yellow. I am always watching for where I am going to come to a stop to really look at the kW meter so I have never seen the in regen/paddle full output for regen.

 

[liresong]

……There is not yet sufficient data to prove coasting would reduce battery degradation over time.….

Chevy Bolt drivers keep saying how reliable their Bolts are. Should be quite a few getting up to 250,000-300,000 miles by now. I’m thinking lots of drivers aren’t treating their EVs as if they were baby technologies & their babies aren’t getting above 250K to 300K mile mark.

 

[Packard V8]

Chevy Bolt drivers keep saying how reliable their Bolts are. Should be quite a few getting up to 250,000-300,000 miles by now. I’m thinking lots of drivers aren’t treating their EVs as if they were baby technologies & their babies aren’t getting above 250K to 300K mile mark.

By what logic would one make that assumption? The average annual mileage is 13,500. By that measure, the oldest Bolt is six years and would have 81,000 miles. Yes, there are lunatic fringe outliers with families driving Uber 24/7, but lots of them above 300,000?

jack vines

 

[BoltEUV]

By what logic would one make that assumption? The average annual mileage is 13,500. By that measure, the oldest Bolt is six years and would have 81,000 miles. Yes, there are lunatic fringe outliers with families driving Uber 24/7, but lots of them above 300,000?

jack vines

Mine is 4 months old with 12k miles and I don't drive for anyone. I'll be out of bumper-to-bumper warranty in 8 months.

 

[Voldar]

Coasting as in no energy used nor regenerated ? True, coasting is more efficient, but I doubt it is THAT more efficient. So just drive and enjoy ! The Bolt EV is a very efficient car either way.
I like to keep sometimes the energy usage to zero, so I play with the acceleration pedal but that’s only for fun…

 

[Dimitrij]

By what logic would one make that assumption? The average annual mileage is 13,500. By that measure, the oldest Bolt is six years and would have 81,000 miles. Yes, there are lunatic fringe outliers with families driving Uber 24/7, but lots of them above 300,000?

jack vines

I do think there are some early adopters who have found a way of beating 250K miles/year out of the Bolt, but this cohort would indeed be a small bunch of outliers (and a few out-liars, perhaps ).

But we can probably state that:

"By now there should be enough Bolt drivers who have driven past the 100K mile battery warranty without major problems [that they have volunteered to report] to create a stastically significant pool of data to discuss the long-term reliability".

 

[jefro]

One should drive a BMW i3 and see how easy they made putting motor in a freewheeling state. No input or output power. I state that driving in N is dangerous. Don't attempt it in Bolt except in car wash mode.