[Cheapergear]

There has been a lot of discussion on driving in L vs D, as to which is more efficient. Maybe I've missed it, but I havent seen anyone try to make a percentage comparison, other than to state that they are very similar. So, I took about 10 commutes alternating between D and L, and did the math, and it showed that, for me, D is 2.3% efficient. My commute is about 30 miles of flat suburban driving, and I got 4.45 m/kwh in D versus 4.35 in L. So, I guess I just reconfirmed that it doesn't make that much of a difference, so you should drive it as you prefer. I was hoping L would be more efficient since I usually drive in L, but that didn't seem to be the case.


Sent from my iPad using Tapatalk

 

[rhodomel]

I second this, especially with my 2017 Chevy Volt. For me, I combine ACC, D, coasting, gentle braking (not getting yellow color) and seldom the paddle wheel to get the best efficiency.

 

[freshcut]

Your math doesn't surprise me. At higher regen levels, you're still subject to about the same 30-40% conversion loss as you'd experience with the lower regen rate of D. The difference is that D allows you to coast further than L resulting in less time on the accelerator pedal, and less power being used to keep you moving before you feel your close enough to let regen in L take over your slowing. Coasting for those couple hundred feet regens a small amount with less loss of momentum so if your light changes, you have less momentum to recover to get back up to speed.

 

[bjrosen]

186 MPGe

It may depend on the terrain. Yesterday on a short trip, 10 miles total, I got 186 MPGe on the outward leg driving in L, I've never done better than 160 in D when driving in that direction. The round trip was 155 MPGe which is still a really good. The roads around me are slightly hilly. This sample is too small to draw any conclusions but it is suggestive. I intend to drive on L for a while to see what happens over a longer period of time.

 

[dannycamps]

I think L is more efficient in hilly areas. There is a road near me that is a speed trap (drops from 55 to 35 during a steep downhill slope). When I reach that part, I put the car in L and just coast down the hill. When I hit the bottom, my speed is effectively reduced and I captured significantly more energy back than if I was using the brakes/paddle.

On most roads, I drive in D and feather the regen paddle to slow down.

 

[Slotracer577]

Hard to tell as other inputs can influence the results. On the Bolt, I felt that L was more efficient and so my brother tried it on his commute, 25 miles each way, on Monday he used low and was 4.7 each way, Tuesday he used D and was 4.5 going to work and 5.9 coming home. Turns out there was an accident on the way home on Tuesday and he drove more stop/go and slower vs Monday. So any difference in d vs l was obscured by the difference in driving conditions.
On the volt I would not expect much difference as the max regen number for l or d with brakes seems to be about equal.

 

[srmarti]

I can imagine there's advantages to each dependent on terrain and driver technique. I don't doubt the OP's observation. I don't think the conclusion that D is always more efficient is justified or even implied.

 

[canehdian]

That that level of difference you're just caught in margin of error and noise. You'd need a very large sample to make any meaningful conclusion.
And at the end of the day, it is 100% determined by the driver - the car does not do anything magically different - it's just responding to your inputs.

tldr; don't worry about it. If you already drive efficiently, the difference is negligible and entirely up to you.

 

[wordptom]

Regenerative braking, it should be mentioned, was designed as an alternative to friction braking for electric cars. How fortunate that it also recharges the battery (free fuel!). It happens when your foot comes off accelerator pedal and the electric motor becomes a generator, even in D!

When choosing D, L, paddle, or modulated rate via brake pedal, think of regen as a braking system, not a recharging system. Regen quantity is time-dependent. A longer gradual slowing in D as you approach that traffic light can generate as much regen as a rapid stop in L just as you reach the light (and the slower slowdown gives the light more time to change to green, allowing you to use less battery energy to accelerate back up to normal driving speed).

 

[Dgcan75]

I find I get most power back into battery by using the paddle for most stopping while in D. I use the brake pedal only at the at the end of a paddle stop to ensure a complete stop as the paddle does not give that final stop. The guessometer usually adds about 1-2 km after a brake from 60- 70km to 0 with the paddle. Right now the guessometer gives me 110km of range after a full charge.

 

[Andy00778]

Driving in D vs L seems to marginally increase the efficiency, but I suspect at the cost of additional use of the friction brakes. Coasting is great but it's easy to misjudge coast down distance exactly with a greater chance of engaging friction brakes near the end of the coast down.

 

[bjrosen]

Driving in D vs L seems to marginally increase the efficiency, but I suspect at the cost of additional use of the friction brakes. Coasting is great but it's easy to misjudge coast down distance exactly with a greater chance of engaging friction brakes near the end of the coast down.

Not if you use your regen paddle. The regen paddle is guaranteed regenerative braking, a light touch on the the brake peddle is likely just regen but it's hard to tell because there is no indicator of how much regen it's using and how much friction it's using. I do almost all of my slowing using the regen paddle, I use the brake peddle fir the last few feet of the stop so the use of friction braking is minimal.

 

[jcanoe]

Not if you use your regen paddle. The regen paddle is guaranteed regenerative braking, a light touch on the the brake peddle is likely just regen but it's hard to tell because there is no indicator of how much regen it's using and how much friction it's using. I do almost all of my slowing using the regen paddle, I use the brake peddle fir the last few feet of the stop so the use of friction braking is minimal.

On my 2017 Volt I use the Classic Enhanced driver information center display mode and it shows the instantaneous power output (-) and power recovery due to regen (+) on the rights side of the display.

 

[ZamboniMan]

Not if you use your regen paddle. The regen paddle is guaranteed regenerative braking, a light touch on the the brake peddle is likely just regen but it's hard to tell because there is no indicator of how much regen it's using and how much friction it's using. I do almost all of my slowing using the regen paddle, I use the brake peddle fir the last few feet of the stop so the use of friction braking is minimal.

I hear all this talk about the "regen paddle." I know my gen 1 doesn't have one, but I can't seem to find a picture of one. Can someone post a pic so I can wrap my mind around this legendary device? Thanks!

 

[Nanabanana]

How fast can you drive in L? I live 1.6 miles from my Office. I usually don't go over 35 miles an hour to and from work. I have always used D. Didn't know you could drive in L without damaging the transmission.

 

[El Dobro]

I hear all this talk about the "regen paddle." I know my gen 1 doesn't have one, but I can't seem to find a picture of one. Can someone post a pic so I can wrap my mind around this legendary device? Thanks!

It's on the back of the steering wheel.

 

[jcanoe]

It is on the backside of the center spoke of the steering wheel, on the left side. On the right side are the Up and Down volume control buttons.

 

[Slotracer577]

How fast can you drive in L? I live 1.6 miles from my Office. I usually don't go over 35 miles an hour to and from work. I have always used D. Didn't know you could drive in L without damaging the transmission.

I have hit 92 in my bolt in L. Same gearing for both L and D, L just uses more regen when you let off.

 

[jcanoe]

They really should have labeled L on the transmission as something else, Max Regen perhaps. The Volt does not have a conventional automatic transmission and there is no low gear in the dual planetary gear set.

 

[Sheldon]

I second this, especially with my 2017 Chevy Volt. For me, I combine ACC, D, coasting, gentle braking (not getting yellow color) and seldom the paddle wheel to get the best efficiency.

I combine D, L, ACC, and occasionally the paddle wheel. Driving in "D" is overall more efficient because you have infinite granularity on the brakes. ACC is a bit abrupt, to be most efficient, though it can be convenient. ACC brakes too late, and hits the gas paddle too quickly as well. "L" makes some sense, but its easier to efficiently feather the brake peddle than the gas peddle. I use the paddle wheel, but I can't figure out when it makes sense to use the paddle wheel since it is usually too abrupt.