Regenerative brake

[W1NGE]

I don’t really agree. 99% of the time when I lift the throttle it is to slow down, not coast. I therefore want the vehicle to decelerate, not coast.
It can not draw more energy to coast at 50 than maintain 50 with foot on the throttle. Otherwise the vehicle would accelerate - that energy has to go somewhere. The car does not work like a gas car, it does not draw power just because your foot is on the throttle, it draws power when there is torque demand.

Rivian has the blended brake design, works very well, a lot better than Taycan. However Taycan is otherwise nicer to drive.

That's not what Frank is saying.

Coasting is more efficient than decelerating with recuperation as you use more energy to get back to the same speed than if you coast and then regain original speed.

You'll find that you can coast for quite some distance at speed energy free than if recuping and then using juice to get back up to the same speed (more energy lost when recuperation is used than added and therefore more required to get back to where you were.

On country roads I'll always engage recuperation as I love the ICE equivalent overrun braking experienced when setting up for a corner and exit.

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[W1NGE]

I notice that the power meter in my Taycan's instrument panel shows much more regen charge (green bar at upper left) when in Regen mode than when not with the foot off the brake (i.e., it can be significant when "coasting" in Regen mode vs. almost zero when "coasting" in Coast mode). I would have a hard time believing that when my foot is on the brake pedal, there's more regen in "Coast mode" than in "Regen" mode.

As for slippery conditions with one-pedal driving: from my personal experience, there is much less slippage than when using two-pedal driving and having to touch the brake pedal. Granted, I am going much slower anyway when it's slippery out, so maybe you and I differ in that regard.

There is no recuperation when coasting - no one is suggesting there is either!

The point is simply that recuperation slows the car down more than when coasting and in order to regain the same speed prior to either event you must use energy which is more than what you would need if coasting.

 

[SpawnyWhippet]

That's not what Frank is saying.

Coasting is more efficient than decelerating with recuperation as you use more energy to get back to the same speed than if you coast and then regain original speed.

You'll find that you can coast for quite some distance at speed energy free than if recuping and then using juice to get back up to the same speed (more energy lost when recuperation is used than added and therefore more required to get back to where you were.

On country roads I'll always engage recuperation as I love the ICE equivalent overrun braking experienced when setting up for a corner and exit.

I absolutely understand that, it's very obvious. But not many people on here seem to understand that one pedal cars also coast when you hold the accelerator at the coast point, they seem to think its just regen or acceleration, no matter how many times I explain it. Also people seem to think its difficult to hold this coast point, despite the fact it comes totally naturally and everyone who drove my car could do it within 15 seconds of trying.
With my Rivian, I can accelerate, coast or regen at any level from almost nothing to moderately hard braking.
My Taycan has less options available, basically just accelerate, coast or very minor brake effect.

 

[F1Ruaraidh]

Your inability to understand does not make it not true

It is clear from tests in racing and, in fact obvious if you consider the engineering.

It is only true if you continuoudly come on and off the throttle or slow more than is neccessary then accelerate back up again.

If you modulate OPD carefully it's no different to regen with the brake pedal, it's just more convenient to triger regen using the throttle pedal.

Racing has nothing to do with road car use. By all means coast in Sport and Sport+ but there really should be a OPD option in normal and range.

 

[The Riddler]

Well, this one’s been fun chaps..!

 

[Jhenson29]

I absolutely understand that, it's very obvious. But not many people on here seem to understand that one pedal cars also coast when you hold the accelerator at the coast point, they seem to think its just regen or acceleration, no matter how many times I explain it.

Coasting vs regen and OPD vs coasting on throttle lift are really two different topics of discussion.

Coasting vs regen: coasting is more efficient. There is no debate to be had about that. Regen is not in and of itself something that is desirable. It is only preferred to friction brakes.

OPD vs coasting on throttle lift: this is an interface discussion and neither, on their own, is more efficient than the other if the brake pedal also uses regen. Which one is more efficient would depend on how they are used, and frankly, all other things being equal, the one that coasts more be more efficient. But again, at the end of the day, that depends on how it’s used. Someone over braking and re-accelerating in a Taycan will be less efficient than someone driving OPD that doesn’t over brake.

That said, the general argument people are making in favor of coasting on throttle lift potentially being more efficient than OPD is that with coasting on throttle lift, there is no regen without a separate deliberate action whereas with OPD, it’s part of the continuum of the throttle position and therefore more likely to occur. I.e., it takes an action to not regen with OPD.

 

[whitex]

I notice that the power meter in my Taycan's instrument panel shows much more regen charge (green bar at upper left) when in Regen mode than when not with the foot off the brake (i.e., it can be significant when "coasting" in Regen mode vs. almost zero when "coasting" in Coast mode). I would have a hard time believing that when my foot is on the brake pedal, there's more regen in "Coast mode" than in "Regen" mode.

That is exactly how it's supposed to work. Taking foot off the accelerator in regen mode (not auto) starts adding regen, pressing the brake adds more regen, though with regen ON there may be a deadband at the very beginning to provide consistent brake feel in regen on or off. I can't test it right now as my car is spending the holidays with its family (other Porsches) in service.

As for slippery conditions with one-pedal driving: from my personal experience, there is much less slippage than when using two-pedal driving and having to touch the brake pedal. Granted, I am going much slower anyway when it's slippery out, so maybe you and I differ in that regard.

What you're comparing is applying braking during the turn with one pedal driving vs. pressing the brake. I usually aim at not braking at all during a turn in extra slippery conditions (do all the braking prior to turning), since ANY braking action, especially on a rear wheels only, can cause the car to slip out of the turn.

 

[whitex]

I absolutely understand that, it's very obvious. But not many people on here seem to understand that one pedal cars also coast when you hold the accelerator at the coast point, they seem to think its just regen or acceleration, no matter how many times I explain it. Also people seem to think its difficult to hold this coast point, despite the fact it comes totally naturally and everyone who drove my car could do it within 15 seconds of trying.
With my Rivian, I can accelerate, coast or regen at any level from almost nothing to moderately hard braking.

Wanna bet that you can't coast perfectly for any longer duration of time (say an hour level highway drive, perfectly means not even a single Watt of regen activated, measured with diagnostic scanner)? Even better, wanna bet that a random person who never drove it, will not be able to sustain coast even for 5 minutes after only 15 seconds of training (as per your post)?

My Taycan has less options available, basically just accelerate, coast or very minor brake effect.

The minimal deceleration is simulating engine braking on an ICE car. It does make it less efficient than coasting, but I prefer to use it as it lets me dial in my speed more precisely.

 

[SpawnyWhippet]

Perhaps you don’t know what coasting is. I’m not aware of any place on the planet that would let you coast for an hour straight. Anyway, this discussion has descended into ridiculous levels of pedantics. I’m out of here.

 

[whitex]

Perhaps you don’t know what coasting is. I’m not aware of any place on the planet that would let you coast for an hour straight. Anyway, this discussion has descended into ridiculous levels of pedantics. I’m out of here.

When I said coasting, I used it incorrectly, I should have said cruising, i.e. "maintain constant speed", in that case only add subtle amounts of power to offset the drag and rolling resistance, but the key would be not never activate regen (again, assuming flat terrain).

 

[W1NGE]

I absolutely understand that, it's very obvious. But not many people on here seem to understand that one pedal cars also coast when you hold the accelerator at the coast point, they seem to think its just regen or acceleration, no matter how many times I explain it. Also people seem to think its difficult to hold this coast point, despite the fact it comes totally naturally and everyone who drove my car could do it within 15 seconds of trying.
With my Rivian, I can accelerate, coast or regen at any level from almost nothing to moderately hard braking.
My Taycan has less options available, basically just accelerate, coast or very minor brake effect.

Most people on the forum would most likely prefer not to have single pedal driving and not least in a Porsche.

Single pedal should remain in the funfair or golf course

In truth, many folk won't bother with coasting either and in particular when highway / motorway driving as cruise control will invariably be engaged for most of the time. In this scenario braking recuperation or more juice is used to maintain the car's speed.

Any Porsche with PDK since 2012 will coast also with the same intent of energy saving.

 

[f1eng]

It is only true if you continuoudly come on and off the throttle or slow more than is neccessary then accelerate back up again.

If you modulate OPD carefully it's no different to regen with the brake pedal, it's just more convenient to triger regen using the throttle pedal.

Racing has nothing to do with road car use. By all means coast in Sport and Sport+ but there really should be a OPD option in normal and range.

No.
The only point is and was that regeneration is NEVER as efficient as coasting, however it is achieved since regeneration is less than 100% efficient. Simple.

If a person is capable of controlling the throttle to not draw power or instigate regeneration in a one-pedal driving car they would equal the efficiency of coasting. I suspect they are few and far between. Anyway you don't do it for long as you do still slow down just more slowlyt.

You surely can understand this??

It has sweet FA to do with a preference for one pedal driving. I suspect the bloke did not realise the Taycan uses regenerative rather than friction brakes.

It isn't that big a deal but enthusiasts of one-pedal driving using bollox to claim it is more efficient gets on my wick.

 

[SpawnyWhippet]

No.
The only point is and was that regeneration is NEVER as efficient as coasting, however it is achieved since regeneration is less than 100% efficient. Simple.

If a person is capable of controlling the throttle to not draw power or instigate regeneration in a one-pedal driving car they would equal the efficiency of coasting. I suspect they are few and far between. Anyway you don't do it for long as you do still slow down just more slowlyt.

You surely can understand this??

It has sweet FA to do with a preference for one pedal driving. I suspect the bloke did not realise the Taycan uses regenerative rather than friction brakes.

It isn't that big a deal but enthusiasts of one-pedal driving using bollox to claim it is more efficient gets on my wick.

jfc, how many times can you miss the fucking point completely. I'm done with this forum.

 

[f1eng]

jfc, how many times can you miss the fucking point completely. I'm done with this forum.

You were trying to make the point that one pedal driving was more efficient than 2 pedal driving.
It is not.
My ONLY point was to point that out.

I don't give a tuppeny f*ck about preference.

 

[Jhenson29]

how many times can you miss the fucking point completely

What exactly is your point in the below then?

I haven't touched the brake pedal in my Rivian for many hundreds or even thousands of miles, and despite being far bigger, heavier and far less aerodynamic, it is almost as efficient around town, because of the regen system. Yesterday I drove my Rivian 200 miles down a mountain and across California back home without touching the brake pedal a single time. I'd have been on the brakes for 40 miles in the Taycan.

Why would using the regen from throttle lift in the Rivian be more efficient than using regen from the brake peddle in the Taycan?

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