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      03-15-2019, 02:22 PM   #1
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This Tesla seems to roll backward - no hold?

Saw this on another forum and it is not my video. I know my brake hold works very well and there is enough power to move forward in D on idle, even on hills. But this Tesla seems to float back. The brake lights are on and I don't see reverse lights. I do notice the brake lights go off then on quick before stopping.

Those of you who own or know, do electric cars float back like a manual car? What about the i3? I would think that is counterintuitive since driving a Tesla is like driving with an automatic gas car, just one foot.


Last edited by BrandBMW; 03-15-2019 at 02:23 PM.. Reason: clarified "on idle"
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      03-15-2019, 04:04 PM   #2
dsad1
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I was driving my wife's model x the other day and was surprised how much it rolled backwards when I let go of the brake on a small hill. I questioned it right away. My car doesn't roll at all on that same hill.

I haven't driven her car in a while, but don't remember ever noticing the issue before. I am wondering if one of the software updates changed something.
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      03-15-2019, 10:31 PM   #3
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An electric motor does not idle like a combustion engine does. There is also no clutch or torque converter. So, in order for the vehicle to come to a stop, the motor must be at zero RPM.

In practice, an EV will often be programmed to creep forward at a low speed when the brake is released. My commuter, a Ford Focus Electric, behaves that way. I believe Tesla’s vehicles can be optionally configured to creep or not.
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      03-16-2019, 08:56 AM   #4
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First autopilot automatically holds when stopped so the person is not using AP.

Tesla cars auto hold if you depress the brake pedal with a bit more force; it's super easy to use (much more user-friendly than BMW's auto hold). However this person did not engage auto hold.

There's an option to turn creep mode off. Creep means the car will behave like regular ICE cars when stopped, meaning if you let go of the brake, it ll slowly creep forward if on flat ground, and not roll back if on a backward slant. This person has turned the creep mode off.

Thus the only way the car rolls backward is if the driver 1) turned creep mode off, 2) did not engage auto hold, and 3) AP is not engaged. Any of these 3 would ensure no backward rolling. Basically with all these off, the person let go of the brake (or just pressing it lightly), and thus car rolled towards where the ground is lower by gravity. Namely, user error.
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