Los Angeles Roadster Road Show

[TEG]

On Elise understeer:
Top Gear - Clarkson driving the Elise - LotusTalk - The Lotus Cars Community

 

[graham]

So if we extrapolate from this example of the Elise (which is probably a mistake) the moral is: The Tesla only understeers if you do not know what you are doing?

 

[doug]

I was going to link to the exact same Elise vid. (I probably posted it somewhere else on this site.)
I'm not sure what to make of Tony's tone. Perhaps he's one of those that see's an expensive sports car as a waste?

Tony's Climate Change Blog: Disappointing Tesla Roadster

 

[graham]

Does any electric car use regenerative braking the way he wants it to be?

While on the subject of brakes, Tesla claim that the car has regenerative braking but it really doesn’t, at least not as normally understood. When you lift off, there is some engine braking effect, as the motor functions as a generator, but there is no attempt to capture energy from actual braking.

I thought the EV1, the RAV4... even the Prius all used engine braking as the regen, and the brake pads as normal friction brakes. Was I mistaken on that? Was he?

 

[DaveD]

Does any electric car use regenerative braking the way he wants it to be?

It's not a car, but the Vectrix electric scooter has an excellent implementation of regenerative braking, IMO.

I expect that the homologation of regenerative braking for cars is going to take some time (and lots of $$$) before we'll see it on the road.

For the safety of myself and others around me, I'm perfectly happy to use old, but reliable hydraulic braking. Even the Vectrix has dual-piston Brembo's front and rear for when I really have to stop quick.

 

[TEG]

I thought the EV1, the RAV4... even the Prius all used engine braking as the regen, and the brake pads as normal friction brakes.

This whole topic has been debated ad nauseum, but my understanding is this:
#1: Engine braking is really a term only to be used for internal combustion engines. If you leave a manual trans ICE vehicle in gear and let off on the accelerator pedal then the piston compression slows you down.
#2: Many EVs have "simulated engine braking" where they use eMotor regen to slow down the vehicle when you let off on the pedal. This regen is used to re-excite the electrons in the battery pack so it helps with range.
#3: Some EVs and Hybrids have "brake blended regen" where application of the brake pedal causes the eMotor regen to increase in strength (slowling the car down more quickly) before they actually engage the friction brakes.

Point #3 is what is being discussed now. As far as I know the Roadster doesn't have "brake blended" regen. In other words no variable regen in response to brake pedal pressure. I think the Prius DOES have variable regen based on brake pedal movement. Combining the fact that the Roadster has regen only on the rear wheels, and doesn't enhance the regen based on brake pedal pressure, the Roadster probably isn't the most optimal regen implementation. *However* it does still have regen. And the reports I have heard state that their implementation does offer the abilility to recapture a substantial amount of energy that would otherwise be lost as brake pad heat. So the concerns over the Roadster regen are somewhat "splitting hairs", saying that it isn't the most optimal regen implementation. In terms of costs, complexity, and regulatory hurdles, it may have been the best path for Tesla to take given how much effort would/will be required to do more.

 

[Cobos]

I might also refer to my own drive of the Roadster. It does have regen similar to engine braking and it works similar to engine braking on a manual ICE. I know because my own car is a manual (a manuel 4 actually ) and the Roadsters braking was similar and very comfortable to use in slow traffic. I fail to see the problem here. (Well excepting my ICE car's manual 4 obviously

Cobos

 

[TEG]

If the regen is strong enough to keep you from using the brake pedal then there is no problem. If you are using the brake pedal a lot, and pushing it hard, then it might have been better off with brake blended regen.

 

[doug]

Some pictures from this event in this guys photostream:
IMG_1328 on Flickr - Photo Sharing!

 

[mike]

Wow - The white looks AMAZING. :biggrin: