It doesn't make sense

[Haven]

Again, I would love it if someone could explain why "coasting" (whatever that is) is some feature that Mach-e doesn't have, and why it should, based on math and science, not what people are saying on other forums about other cars.

You get coasting on a Mach E in Whisper mode and one pedal turned off. What am I missing here?

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[ctenidae]

It's a "smart-regen" system because on the highways it is more efficient to coast.

How is this possible? There is no branch of physics that would support this. Thermodynamically impossible. At the very least, you have to use energy to regain the speed you lost while coasting, and you wouldn't have reclaimed any of it while decelerating.

Converting the kinetic energy of speed into the potential energy of battery charge is always better than converting kinetic energy to heat. If anyone can show me math that contradicts that I'll change my mind, and then nominate them for a Nobel Prize in physics, because they've discovered perpetual motion.

 

[Socalsp3]

How is this possible? There is no branch of physics that would support this. Thermodynamically impossible. At the very least, you have to use energy to regain the speed you lost while coasting, and you wouldn't have reclaimed any of it while decelerating.

Converting the kinetic energy of speed into the potential energy of battery charge is always better than converting kinetic energy to heat. If anyone can show me math that contradicts that I'll change my mind, and then nominate them for a Nobel Prize in physics, because they've discovered perpetual motion.

if you are in a situation such as on highway and do not want to slow down, kinetic to regen to kinetic is not as efficient as staying in kinetic because you always lose energy in the conversion.

mme and nontesla evs have brakes that regen. you do not need 1pedal to regen.

 

[voxel]

How is this possible? There is no branch of physics that would support this. Thermodynamically impossible. At the very least, you have to use energy to regain the speed you lost while coasting, and you wouldn't have reclaimed any of it while decelerating.

Converting the kinetic energy of speed into the potential energy of battery charge is always better than converting kinetic energy to heat. If anyone can show me math that contradicts that I'll change my mind, and then nominate them for a Nobel Prize in physics, because they've discovered perpetual motion.

I’m not sure we are talking about the same thing. Smart regen is just radar/vision based 1PD regen triggering

Traffic: 1PD regen on.
No traffic: 1PD off. Coasting. No braking.

There’s no need for 1PD regen on the highway. It’s pointless to convert kinetic energy to battery energy which then gets converted back to kinetic energy. Might as well coast.

Remember all EVs use regen as braking before apply physical brakes.

 

[ctenidae]

if you are in a situation such as on highway and do not want to slow down, kinetic to regen to kinetic is not as efficient as staying in kinetic because you always lose energy in the conversion.

mme and nontesla evs have brakes that regen. you do not need 1pedal to regen.

But when coasting, you are slowing down. Friction, and all that. Therefore you are losing energy by coasting. If you don't want to slow down, you're not coasting, you're maintaining your speed. Maintaining your speed is more efficient than slowing down and speeding back up.

 

[Socalsp3]

But when coasting, you are slowing down. Friction, and all that. Therefore you are losing energy by coasting. If you don't want to slow down, you're not coasting, you're maintaining your speed. Maintaining your speed is more efficient than slowing down and speeding back up.

add regen and you slow down even more. regen doesn't recoup the energy already lost to drag. it only recoups energy lost to friction braking.

 

[ctenidae]

I’m not sure we are talking about the same thing...

There’s no need for 1PD regen on the highway. It’s pointless to convert kinetic energy to battery energy which then gets converted back to kinetic energy. Might as well coast.

This is physically impossible. If you stop applying motive force, friction slows the car down - it converts kinetic energy into heat. Unless you're in a physical world where that does not hold true, and "coasting" is something other than not applying motive force, it is completely wrong to say that coasting is more efficient. It can not be.

Heat = lost energy. Coasting generates heat through friction. Therefore, coasting is losing energy. Period. Point out where that's wrong.

 

[ctenidae]

add regen and you slow down even more. regen doesn't recoup the energy already lost to drag. it only recoups energy lost to friction braking.

No, you can regen an amount that slows you down the same as coasting. You're losing the speed either way, but with regen you get some of it back.

 

[Socalsp3]

No, you can regen an amount that slows you down the same as coasting. You're losing the speed either way, but with regen you get some of it back.

you're losing more speed when you regen, try whisper vs unbridled modes in your mme.

 

[voxel]

This is physically impossible. If you stop applying motive force, friction slows the car down - it converts kinetic energy into heat. Unless you're in a physical world where that does not hold true, and "coasting" is something other than not applying motive force, it is completely wrong to say that coasting is more efficient. It can not be.

Heat = lost energy. Coasting generates heat through friction. Therefore, coasting is losing energy. Period. Point out where that's wrong.

Coasting is not generating heat. You are basically freewheeling. Yes natural tire friction and wind resistance happens but that always happens in 1PD regen.

There's no free lunch and no lossless energy transfer so avoiding forced 1PD regen is ideal. Folks with VW ID.4s have documented B and D drive modes. The ID.4 D mode does not apply regen when you let go of the accelerator so it behaves like an ICE car. It's more efficient than B (regen but not 1PD) on the highway.

 

[Av8tor]

All of this is going to make my head explode. WHISPER, TRY WHISPER.

 

[voxel]

A strong argument for 1PD is safety - specifically emergency maneuvers. i.e The Ioniq 5 only passes the highest speed moose test with 1PD on. Without it, it only passes as much lower speed.

The argument against 1PD is on snow/ice where regen causes traction control issues.

 

[ctenidae]

you're losing more speed when you regen, try whisper vs unbridled modes in your mme.

Losing more speed than what? I can slow down in 1PD just as slowly as I could coasting, and might just pick up a spot of juice. If you're going 65 and coast to a stop, all of the energy you had is now gone. It is now heat, dissipated into the atmosphere. Friction slows you down (air, tire, bearings, etc) and generates heat. If you regen from 65 to 0 you would recoup some of that energy.

Granted, if you are generating electricity you will slow down faster than straight coasting. Might be a miniscule amount faster, depending on the load you're putting on the generator, but if you are in 1PD and slowing down exactly the same amount as if you were coasting, then you are not generating any electricity, so you are, effectively, coasting. Which means you have replicated a "coast mode" by using your right foot correctly. Which takes a bit of effort, but is more natural to me, at least, than toggling some switch and having to swap back and forth between modes.

How about this:

In certain limited circumstances, you can simulate coasting in 1PD by lifting your foot just enough to slow down without engaging any regen. That does require some active engagement on the driver's part.

If you have 1PD turned off and you need to slow down faster than straight coasting, you must apply the brakes. If you use friction brakes, you are converting kinetic energy into waste heat. If you misjudge and brake too much, you're wasting more energy. If you use regen brakes, then you are simulating what 1PD can do more efficiently.

If you want or need to slow down any faster, no matter how little, than straight coasting, regen is more efficient.

 

[ctenidae]

The argument against 1PD is on snow/ice where regen causes traction control issues.

I've heard this one, too. My rebuttal is that the traction control system knows how much it can slow the car down without breaking traction. To me, the evidence of this is in the name, "traction control," and in 3 winters of driving in the Northeast with 1PD on.

My old 6-speed BMW had no idea what was underfoot, and I could lock up the rear wheels on snow by just letting off the gas while in gear. That was always fun.

 

[Socalsp3]

Losing more speed than what? I can slow down in 1PD just as slowly as I could coasting, and might just pick up a spot of juice. If you're going 65 and coast to a stop, all of the energy you had is now gone. It is now heat, dissipated into the atmosphere. Friction slows you down (air, tire, bearings, etc) and generates heat. If you regen from 65 to 0 you would recoup some of that energy.

Granted, if you are generating electricity you will slow down faster than straight coasting. Might be a miniscule amount faster, depending on the load you're putting on the generator, but if you are in 1PD and slowing down exactly the same amount as if you were coasting, then you are not generating any electricity, so you are, effectively, coasting. Which means you have replicated a "coast mode" by using your right foot correctly. Which takes a bit of effort, but is more natural to me, at least, than toggling some switch and having to swap back and forth between modes.

How about this:

In certain limited circumstances, you can simulate coasting in 1PD by lifting your foot just enough to slow down without engaging any regen. That does require some active engagement on the driver's part.

If you have 1PD turned off and you need to slow down faster than straight coasting, you must apply the brakes. If you use friction brakes, you are converting kinetic energy into waste heat. If you misjudge and brake too much, you're wasting more energy. If you use regen brakes, then you are simulating what 1PD can do more efficiently.

If you want or need to slow down any faster, no matter how little, than straight coasting, regen is more efficient.

you can go 2-3x or more further coasting than regen before stopping depending how hard you set regen. friction brakes activate only with hard braking. your mme will give you a score on how well you brake. im usually at 100% for regen with brakes

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