One pedal drive (vs) Brake regen

[Space Ghost GT]

No regenerative braking is 100% efficient, including the MME. But the efficiency of the internal charger/inverter is pretty good at better than 90%. Better to recover most of the kinetic energy via regenerative braking than to waste it all as heat from friction braking only.

If you are coasting you are literally only fighting the drag of the bearing which is far more efficient than constantly being in regen while off throttle. When your are decelerating you are losing efficiency regarding mi/kWh as you are absolutely not recouping 100% of the kinetic energy due to the battery and inverter.

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[Space Ghost GT]

No regenerative braking is 100% efficient, including the MME. But the efficiency of the internal charger/inverter is pretty good at better than 90%. Better to recover most of the kinetic energy via regenerative braking than to waste it all as heat from friction braking only.

The thing you have to set is the impulse of the energy of the regen system. It has the buffer the energy before that battery and accept it. Just like when you plug into a DCFC it just doesn’t jam 150kw instantly into the battery as the battery can’t take it. It has to ramp up, the same for regen. So the inverter has to burn the edge of that recouped impulse. If the car had a super capacitor bank it’d be a different story.

 

[devmach-e]

The thing you have to set is the impulse of the energy of the regen system. It has the buffer the energy before that battery and accept it. Just like when you plug into a DCFC it just doesn’t jam 150kw instantly into the battery as the battery can’t take it. It has to ramp up, the same for regen. So the inverter has to burn the edge of that recouped impulse. If the car had a super capacitor bank it’d be a different story.

There’s a difference between ramp-up at a DCFC station and that of regenerative braking. The ramp up at the station has more to do with the off-board equipment coming up to the requested voltage and current that the car wants. There’s no internal charging hardware involved.

If you hook up CarScanner, you’ll see that when you hit the brakes, regenerative braking kicks in immediately. There’s no ramp up time like at a DCFC station. If there is any delay, it is the millisecond range. The amount of energy potentially wasted as heat is in the tens of watts.

 

[Space Ghost GT]

There’s a difference between ramp-up at a DCFC station and that of regenerative braking. The ramp up at the station has more to do with the off-board equipment coming up to the requested voltage and current that the car wants. There’s no internal charging hardware involved.

If you hook up CarScanner, you’ll see that when you hit the brakes, regenerative braking kicks in immediately. There’s no ramp up time like at a DCFC station. If there is any delay, it is the millisecond range. The amount of energy potentially wasted as heat is in the tens of watts.

It’s still not a straight pipe conversion of kinetic to storable electrical energy. So 1pd is not the most efficient way to drive and EV. Porsche proved it

 

[devmach-e]

It’s still not a straight pipe conversion of kinetic to storable electrical energy. So 1pd is not the most efficient way to drive and EV. Porsche proved it

I fail to see how Porsche proved it is less efficient just because they chose not to implement 1-pedal driving.

It is a pretty straight forward path from regenerative braking to the battery, whether it is via one-pedal or the actual brake pedal. Both turn the electric motor(s) into a generator to slow the car down.

 

[PA Bob]

I recently tried out 1PD over about 200 miles of driving in a day, over freeway and in town, and absolutely love it. What gets me grinning is coming to and stopping at a stop sign without having to touch the brake pedal at all. I do wonder when the brake lights come on, though.

The brake lights come on for regen braking.

 

[PA Bob]

I have other ICE car and just want to make sure I wire my brain correctly.
1PD also auto holds right, because my ICE car won't and I don't want to run into things

Yes. 1PD hold when stopped

 

[Space Ghost GT]

I fail to see how Porsche proved it is less efficient just because they chose not to implement 1-pedal driving.

It is a pretty straight forward path from regenerative braking to the battery, whether it is via one-pedal or the actual brake pedal. Both turn the electric motor(s) into a generator to slow the car down.

Coasting provides the best efficiency. If you hypermile with whisper mode you’re going to go father with less energy used than 1pd. It’s just facts. I don’t know what else to say.

 

[mkhuffman]

I would recommend against shifting on the fly unless you have a very steady hand. adaptive cruise control works really well and does adjust the throttle to find 'coast' when possible....

if you have a ODB2 and CarScanner on your phone, you can see exactly kW going in and out

Are you worried about accidentally shifting it in to Reverse? I don't think it will let you do that if you are at speed. I did a lot of neutral coasting testing a few months ago and it never caused a problem. And it is very cool how it is a true coast, with no regen and no power used. Perfectly neutral.

 

[mkhuffman]

Coasting provides the best efficiency. If you hypermile with whisper mode you’re going to go father with less energy used than 1pd. It’s just facts. I don’t know what else to say.

This is a frustrating debate.

Do you have the Porsche report and data that backs up the claim that "Porsche proved it"? Not saying they didn't, but I would like to read the report and see the data. If you don't have it, then you probably should stop using that argument.

I do agree with you that coasting is the most efficient. But you can coast using 1PD, so I don't agree that 1PD is less efficient than 2PD. Both modes allow coasting. You can also use Neutral to coast regardless of the drive mode.

 

[dtbaker61]

Various hypermiling techniques will lead to more miles/ kwhr.... but beyond using regen braking versus mechanical, the differences at just lipstick on a pig.

The MME will never be super efficient hypermilet, or a dragster, or a competitive autox racer. It's too big, too heavy, and set up to balance performance with range

 

[acosmichippo]

Better to recover most of the kinetic energy via regenerative braking than to waste it all as heat from friction braking only.

that's not what happens with 2pd though. you still get plenty of regen with the brake pedal as long as you don't slam it. So to me, 2pd in whisper is the best of both worlds - coast as much as possible, then light regen braking when you decide you need it.

 

[devmach-e]

that's not what happens with 2pd though. you still get plenty of regen with the brake pedal as long s you don't slam it.

I know. I’m more referring to the fact that regenerative braking is a great alternative to just wasting braking force as heat.

 

[acosmichippo]

yeah of course, I don't think anyone is disagreeing with that.

 

[Geesh]

What I dont get, is why 1PD driving won't get me perfect braking scores, since I'm not using mechanical breaks? I get better scores with 2pd (or if I make sure 1pd isn't slowing so much... ie. Driving like an old lady)

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