Does the Roadster Sit Still?

Does the Roadster Sit Still?

If you're in an ICE car with an automatic transmission the car tries to slowly roll forward. If you're in a manual transmission ICE car you have to press the clutch or pull the car out of gear and then it rolls forward or backward unless you're on flat ground.

I'm just curious about what the Roadster does when drive is selected and you're stopped. My guess is that it will sit still and you won't have to hold the brake as it would be a waste of battery power to mimic an automatic transmission and have the car slowly roll forward. If the car does indeed sit still on flat ground while stopped, what happens if you stop going up a hill? Will the motor allow the car roll backwards?

Tesla 940 | 10 novembre 2010

My car rolls forward at about 2 mph. On a hill it will either roll forward, stay stationary, or roll backwards depending on the slope of the hill. It seems to mimic an ICE with an automatic transmission.

ggr | 10 novembre 2010

If you're on a slight hill, where the tendency to roll backward is exactly balanced by the bias to go forward, my car shows a continuous draw of 3 amps when I have my foot off the brake, but when I put my foot on the brake, it drops to 1 amp.

I think (just guessing) that it is intentional, to make people hold the brake when they want to be stationary. Otherwise a gust of wind, or being rear-ended, might make the car move when you don't want it to.


SteveU | 10 novembre 2010

Yes, it is intentional that the Roadster creeps forward when your foot is off the brake. Tesla had a variety of explanations for this design choice. The one that I heard most frequently repeated by Tesla employees was to keep you from accidentally getting out of the car while it was on and "in gear" (well, switched to go forward). There were many discussions about this design decision two years ago where the general consensus of the owners at that time was that this design decision was wrong. Personally I think the decision was right, but for the reason Greg mentioned (which I've never heard from a Tesla employee) rather than for the reasons I have heard.

Douglas3 | 10 novembre 2010

I think it's a good idea, for a few reasons.

First of all, it entices you to hold down the brake while you're at a stop light. Speaking as someone who has been rear-ended twice (not in my Roadster, fortunately!) doing that saved me from whacking the next car in line. I think this is the most important reason.

Second, it ensures that the brake lights are on. The regen brake lights only turn on as long as you are actually decelerating.

Third, it helps if you're on a steep uphill and are moving the foot from the brake to the accelerator. I'm used to manual transmissions, so it's not a big deal for me, but most people these days only drive automatics.

The thing about getting out of the car with it in Drive sounds silly to me. Personally I tend to always take my keys with me regardless of how short a stop it is... it's not like you have to START the car. ;-)

BladeRunnings | 11 novembre 2010

Thank you for all your answers and explanations!

It sounds like they designed the car to behave similar to an automatic transmission in this respect. Either way it isn't really a big deal, I was more curious than anything. I can see how it would help on steep hills, but I'm also very comfortable driving manual transmissions.