Driver-adjustable Regen

[SoCalGuy]

This is GREAT news.

Now to get it where it can be adjusted quickly while driving. The AC Propulsion E Box has a 4" mechanical slider on the dash. As i have said before I would love a dedicated steering wheel stalk to adjust regen radidly when approaching a traffic jam (more) driving highways (less) heading into the canyons (more) and general hypermiling (less).

I don't think Fanz reads these boards but if there is an engineer reading this please pass it on the design team as well.

That's what the Karma has - three regen braking modes that are accessible via a paddle shifter behind the steering wheel (D is minimal, Hill 1 is moderate and Hill 2 is aggressive). It's super fun to use! Contributes to the experience/theater of driving the car.

 

[ElSupreme]

I want 'panic stop' powered regen.

But really I will have it set at maximum whenever I drive.

 

[Doug_G]

I really want to know what the "Jack" button does.

Obviously it lifts one wheel off the ground for you. :biggrin:

 

[gg_got_a_tesla]

Obviously it lifts one wheel off the ground for you. :biggrin:

Yeah, how about that "Bounce" option?!

How to Bounce a Car | eHow.com

 

[vfx]

Yes, the blog posts says that 'some will like a little more and some will like a little less.' That is not available with just two buttons. I would like to see a slider with Aggressive regen on one side, and less regen on the other.

Agreed on the slider. Sadly it's just two settings. The Fisker has three on the tree. Now that is awesome! (and kinda retro)

 

[daniel]

I agree that driver-adjustable regen is a good idea. That said, I've gotten used to, and mostly like, the hard regen on my Roadster. For freeway driving, though, I think it would be easier without it. That makes adjustable a good idea.

 

[tdelta1000]

Another want from the consumer turned into a reality by Tesla Motors. Way to go Tesla Motors!!!

 

[dsm363]

Another want from the consumer turned into a reality by Tesla Motors. Way to go Tesla Motors!!!

I agree. This really makes me think they are working on some sort of solution to solve people's concerns about storage pockets in the car/center console.

 

[Doug_G]

Agreed on the slider. Sadly it's just two settings. The Fisker has three on the tree. Now that is awesome! (and kinda retro)

Personally, I would only ever set it to minimum or maximum. Maximum 99% of the time, and minimum if I wanted to try it out on a track.

 

[AnOutsider]

Personally, I would only ever set it to minimum or maximum. Maximum 99% of the time, and minimum if I wanted to try it out on a track.

Wouldn't higher regen be an asset on the track? Less use of the brakes == less heat generated. I think 3 stages would be best (normal, high, low), but I've never driven a Roadster and clearly not a Model S, so maybe what they have works.

 

[JRod0802]

Wouldn't higher regen be an asset on the track? Less use of the brakes == less heat generated...

Not from what I've read. The regen is only on the rear wheels, which screws up the dynamics of the car if you let your foot off the gas while going around a corner. I think it makes it easier for the car to spin out.

You can try to regulate it with your foot to be perfectly in the middle "coast" spot, but it'd be easier to just turn it off.

 

[Robert.Boston]

My guess -- not even an educated guess -- is that each regen setting requires a number of sub-systems to be carefully coordinated. Therefore, a slider doesn't work well. Also therefore, adding variations should be something that future software updates can accomplish.

 

[Doug_G]

Wouldn't higher regen be an asset on the track? Less use of the brakes == less heat generated. I think 3 stages would be best (normal, high, low), but I've never driven a Roadster and clearly not a Model S, so maybe what they have works.

No. Before entering a corner you need to brake hard to transfer weight onto the front wheels, which aids the turn-in. During maximum turning you need to have neutral acceleration so you don't exceed the grip capabilities of the tire. Once you're passing the apex and unwinding the steering you're getting back onto the accelerator. To do a corner properly requires some finesse, and the regen definitely gets in the way. When you lift off the brake it tends to alter the weight transfer away from the front wheels, and that not only reduces turn-in but also unsettles the car (i.e. the suspension).

I've mostly done autocross with the Roadster, which is a bit more forgiving, but I've done a CASC-OR race school with it, and it was a bit of a problem. My instructor was very experienced and even he had some trouble adapting. We'd have to move very quickly from the brake to the accelerator, yet press only very slightly to keep the acceleration neutral. It's hard to get it just right, and even then I don't think the end result is ideal.

You also have a risk of snap oversteer if the regen kicks in while you're turning. You can do that in well balanced RWD gas car, too, but the regen is rather more powerful. Last year during an autocross event I was distracted by hitting a cone, and I lifted off for a split second. The result was a spectacular spin just before the stop box - right in front of the spectators. :redface:

 

[vfx]

Personally, I would only ever set it to minimum or maximum. Maximum 99% of the time, and minimum if I wanted to try it out on a track.

If the max would be the equivalent of slamming on the brakes and snapping your neck then I doubt that is the case (try driving a MiniE for example). No, an adjustable slider with say, 8 or ten settings is ideal.

 

[William13]

I don't know how to race a car but at least in the past race cars were manual transmision. The regeneration is probably very similar to that pull of an engine if the clutch is not depressed. The low setting for regen might be very much like a manual transmission.

 

[Doug_G]

I don't know how to race a car but at least in the past race cars were manual transmision. The regeneration is probably very similar to that pull of an engine if the clutch is not depressed. The low setting for regen might be very much like a manual transmission.

I don't know about the Model S, but the regen on a Roadster is much stronger than a manual transmission.

 

[spatterso911]

How will weight transfer be affected with the low CoG? Will braking have the same effect on weight transfer? Lots to consider here, and I don't have a real reference point. Even open wheel racers have the majority of their weight above the axles.

 

[Doug_G]

How will weight transfer be affected with the low CoG? Will braking have the same effect on weight transfer? Lots to consider here, and I don't have a real reference point. Even open wheel racers have the majority of their weight above the axles.

Clearly it will reduce the weight transfer. In most respects this will be an improvement. You have more traction overall if the weight is balanced on all four wheels.

It will have some effects that some people consider a minus; for example, less weight transfer to the front might mean more understeer at turn-in. But overall there will be more traction through a corner. Who knows, the Model S might turn out to be an excellent track car.

 

[spatterso911]

I remember reading somewhere that the rear wheels will have better performance with turning as well, as a result of the weight being between the axles. Does anyone know more about that?

 

[goyogi]

The next roadster if equipped with awd and with independently adjustable regen in the front and back would help.