What does Low Gear do?

[campfamily]

What specifically happens when the car is shifted into L? There isn't a lower gear for the car to shift into. Does it increase the amount of regeneration, or something else?

Thanks,

Keith

 

[brogult]

I think the only thing we know for sure is that it increases regeneration. Others have speculated it may increase starting torque and the owners manual says that using L will reduce efficiency and range, but I haven't noted either.

 

[WattsUp]

I think the only thing we know for sure is that it increases regeneration. Others have speculated it may increase starting torque and the owners manual says that using L will reduce efficiency and range, but I haven't noted either.

It doesn't "increase" regeneration. The regeneration always works the same way, whether using D, L, or pressing the brake pedal enough to engage regeneration.

The D and L "gear" selections simply control the "preset" level of motor resistance which, in turn, affects the rate of regeneration, but only because D and L select different preset levels, not because regeneration itself is "improved" or "increased".

Coasting in D is just like applying the regenerative braking using a standard level of motor resistance (which is why the car always slows down at the rate it does when you lift your foot off the A pedal). Coasting in L is just like applying the regenerative braking a bit more. In other words, "more than D". That is, there is more motor resistance while coasting in L than in D (so the car slows down faster). But, that's all.

While coasting in D, you could have also equivalently pressed the brake pedal just the right amount to cause the motor to have the same level of resistance as coasting in L, and would be regenerating at exactly the same rate as L.

Regenerative braking, coasting D, or coasting in L are all the same thing... just varying levels of motor resistance (the motor acting as an electric generator) recapturing energy, which is stored back in the battery.

 

[campfamily]

Thanks for the explanation, this makes perfect sense. Theoretically, then, I could drive around in "L" all of the time, and only use the acceleration pedal to vary my speed. If I time it right, I would never have to use the brake pedal. Only danger with this is getting rear-ended, since I will be slowing down without the brakes, hence the brake lights will never come on. I mention this because, when I drove the BMW i3, the rate of deceleration when you release the acceleration pedal was much greater than any other car I had driven, including the FFE. I was told that "coasting" in an i3 would actually cause the brake lights to illuminate, since the car slowed down so quickly. When I drove it, it became a game to see how far I could go without ever touching the brake pedal. Once I had been driving it for a while, I could go miles without having to use the brakes.

Keith

 

[tinilk]

I drive around in 'L' all the time, except with cruise control on. Before the FFE I drove a manual and the higher regen rate feels normal, like engine braking in my old car. I'm so used to it that I'll get flustered for a second if I left it in 'D' and the car keeps coasting. Even more so when leaving home with a fully charged HVB and regen braking is disabled for the first mile or so to protect the battery.

You do still need the brake pedal though. I haven't driven an i3, Tesla or Golf EV, but I expect I'd appreciate the stronger regen braking that they all have.

 

[triangles]

I drive around in 'L' all the time, except with cruise control on. Before the FFE I drove a manual and the higher regen rate feels normal

:lol: My gas car that I drove before the FFE and when I need to go farther is a manual. I was horrified at first by the slight regen in "D" when I lifted off the accelerator. I'm so used to coasting a lot with the clutch pushed in. I guess we must operate our manual transmission cars very differently! I've adapted by not taking my foot off the accelerator or popping the shift lever into N to disable the regen. I wish there was a way to disable regen when you lift off the accelerator!

 

[hybridbear]

I've adapted by not taking my foot off the accelerator or popping the shift lever into N to disable the regen. I wish there was a way to disable regen when you lift off the accelerator!

This is what I do too. I'm often shifting back and forth between N, D & L... I also wish there was a way to get the free rolling of N without having to shift to it.

 

[campfamily]

I wish there was a way to disable regen when you lift off the accelerator!

Just curious, why do you want to disable regen?

 

[sefs]

If you can coast and use the energy to go farther without using power for a longer period it is more efficient than regen braking and then immediately having to use power to accelerate again. It's more efficient to leave the energy as kinetic than taking it from kinetic to electric to chemical to electrical and finally back to kinetic.

 

[hybridbear]

If you can coast and use the energy to go farther without using power for a longer period it is more efficient than regen braking and then immediately having to use power to accelerate again. It's more efficient to leave the energy as kinetic than taking it from kinetic to electric to chemical to electrical and finally back to kinetic.

Exactly! This is why I try to coast in Neutral when safe & appropriate.

 

[toddh]

I agree entirely, I would love to be able to reduce the regen. I also shift between N,D and L.

One good reason to use N is long slow downward grades. Not many but we have a few here in Texas. I am learning to apply only a slight amount of accelerator pedal to keep it between actual power being applied and regen kicking in(basically coasting). But its a fine line. I can see real benefit in disabling regen entirely.

I drove a Honda Insight before this and I spent a good deal of time with the clutch in coasting because it was more efficient. Easy to see on a car like that because it shows your instantaneous mileage go up to 150 mpg and in really increased your average.

If you have not already then try it in the FFE. Sift into N on downgrades and if its any length you will see your Surplus go up.

 

[WattsUp]

One good reason to use N is long slow downward grades. Not many but we have a few here in Texas. I am learning to apply only a slight amount of accelerator pedal to keep it between actual power being applied and regen kicking in(basically coasting). But its a fine line. I can see real benefit in disabling regen entirely.

Still not a good reason. Especially going downhill, there is no reason to disable regen.

In the FFE, you can use cruise control to recover downhill energy "perfectly". Shift to L and set the cruise and your speed will be limited going downhill (provided the decline isn't too steep for the motor resistance to overcome).

Then you get the benefit of regen while going down the hill. In N, you would lose it all.

 

[michael]

I believe Watts Up is exactly correct. Maintain a steady speed with the car in gear and it will either consume or regenerate exactly the amount of energy needed or in excess as the case may be.

if you are in neutral and apply the brakes at all, the energy is wasted to heat.

The reason L is generally less efficient than D is that the pedal is more touchy, greater tendency to go between power and regeneration.

 

[hybridbear]

Driving in N is more efficient as long as you don't brake while in N. Regen is never 100% efficient.

 

[WattsUp]

Driving in N is more efficient as long as you don't brake while in N. Regen is never 100% efficient.

Yes, but when going downhill (the topic at hand), regen recovers "free" energy while neutral does not. It converts kinetic energy into electricity that would otherwise be lost. If you go downhill in neutral in an FFE, You might as well be driving an ICE.

 

[scottt]

I find myself using L more and more. Almost to the point where I think I'll use it 100% of the time.

 

[hybridbear]

Driving in N is more efficient as long as you don't brake while in N. Regen is never 100% efficient.

Yes, but when going downhill (the topic at hand), regen recovers "free" energy while neutral does not. It converts kinetic energy into electricity that would otherwise be lost. If you go downhill in neutral in an FFE, You might as well be driving an ICE.

If you go downhill in N the potential energy is converted to kinetic energy. There's one hill I frequently drive on a road where the speed limit is 35 MPH. There is about a half block before the descent begins after pulling away from a stop sign. I will usually only accelerate to about 20 MPH & then shift to N right before beginning the descent. The descent brings the car up to about 40 MPH by the bottom of the hill. Once I reach the valley & begin going back up the other side I press slightly down on the accelerator & shift back to D to maintain my speed up the other side of the hill. This is more efficient than accelerating to 35 MPH & using regen down the hill.

 

[Elektra]

Disclaimer: driving downhill in neutral is dangerous and should only be attempted by a trained professional. :lol:

 

[hybridbear]

Disclaimer: driving downhill in neutral is dangerous and should only be attempted by a trained professional. :lol:

True. You have to be ready. I always keep my hand on the shifter when coasting in N & my foot covering the brake pedal.