Regen braking - full stop

[beatle]

When driving my friend's model 3, I notice that his regen braking will bring him to a full stop which allows for easy one pedal driving in most cases. My S trails off regen around 6 mph to the point that the car will free wheel (for a considerable distance on level ground). I always have to switch to the traditional brakes to come to a full stop in traffic.

Creep is off and regen braking is set to standard. I don't see any other options that would let me come to a full stop using only regen. Am I missing something or are the cars just that different?

 

[DavidB]

You are not missing something. The cars are just that different.

 

[SSedan]

Different motor types the AC indication motor on the S won't produce at as low an rpm.

 

[TMThree]

Regen on model 3 doesn't bring you to a stop. It can't because regen stops doing anything at 5 mph.

Source: I own a model 3 and have driven 3 others.

 

[serendipitous]

Lobbing my opinion into the void: I also wish I could fully one pedal drive. Out of curiosity, anyone know if it's an electromagnetic impossibility to add electro drag down to a stop? Does it just become inefficient to have an inverter drag the motor down to zero?

 

[3Victoria]

Or Tesla could give the option to gently apply the brakes for the final 5 mph. One can always apply more brakes if necessary.

 

[woof]

Regen to full stop, and no rolling back, is one of the only things I miss from the BMW i3. True one pedal driving

 

[beatle]

Hmm, I was pretty sure the 3 would bring me to a full stop.

I figure this must be a software thing and not hardware. The 3 does have a permanent magnet in the rear, but I did not think the RPM would actually matter in being able to perform any regen.

Seamlessly transitioning from regen to mechanical brakes via software is a nice thought. Maybe that can be added in the future.

 

[Tessaract]

Lobbing my opinion into the void: I also wish I could fully one pedal drive. Out of curiosity, anyone know if it's an electromagnetic impossibility to add electro drag down to a stop? Does it just become inefficient to have an inverter drag the motor down to zero?

The regen drag is proportional to vehicle speed. Mathematically, it's impossible for such an arrangement to bring speed to zero. However, rolling friction with (bearings, tires, etc.), as well as a slight application of "real" brakes might do the trick.

 

[jerry33]

Lobbing my opinion into the void: I also wish I could fully one pedal drive. Out of curiosity, anyone know if it's an electromagnetic impossibility to add electro drag down to a stop? Does it just become inefficient to have an inverter drag the motor down to zero?

If you have the system regen brake to zero, then some of the braking energy needs to come from the battery which reduces range. Also, if you don't exercise the brakes regularly, they will build up contaminants and rust (except for perhaps the $4K/wheel ceramic brakes), or they will have to drag all the time.

 

[beatle]

I know from my days playing with electric RC vehicles, the ONLY braking available is regen braking and the motor had no problem bringing the vehicle to a halt in a hurry. Granted we're talking huge differences in scale, but the principle should remain the same.

The regen braking doesn't suffice for every situation - sudden stops or more aggressive driving require mechanical brakes.

 

[Ande]

I know from my days playing with electric RC vehicles, the ONLY braking available is regen /QUOTE]

...wrong. the mass, gear ratio, and type of motor is not comparable.

For a full-size vehicle, you'll expect full stop, after nice and predictive deceleration. The only way to achieve it, even downhill, is software that apply reverse power to motor, or not to waste more energy, use friction brakes when regen energy is too low

 

[Dithermaster]

Sounds like maybe some changes in this area are coming soon? Elon said something about one pedal driving in the Q3 call, and some early access firmware seems to indicate that regen braking has changed. We'll see if it includes full stop.

 

[dark cloud]

I know from my days playing with electric RC vehicles, the ONLY braking available is regen braking and the motor had no problem bringing the vehicle to a halt in a hurry. Granted we're talking huge differences in scale, but the principle should remain the same.

The regen braking doesn't suffice for every situation - sudden stops or more aggressive drivinginertia

in a word: inertia. A good example is imagining having both a person and a mouse in identical ice skates pushed to an initial speed and released. The mouse will stop shortly while the person will coast for many metres. The larger mass (inertia) compensates for the frictional losses more so than the mouse.

 

[ICUDoc]

the ONLY braking available is regen braking

This isn't quite true.
The battery is used in reverse to slow the car quickly, not just as a sink for current but as a source of reverse current.
In general, Teslas will now have motor braking down to ultra-low speeds after the latest software update.

 

[Tessaract]

This isn't quite true.
The battery is used in reverse to slow the car quickly, not just as a sink for current but as a source of reverse current.
In general, Teslas will now have motor braking down to ultra-low speeds after the latest software update.

That's an interesting possibility. Do you have any source of (reliable) info that would indicate that "reverse thrust" is being used or introduced by Tesla in a recent SW release?

 

[Merle]

Would the number of motors play a role?

A performance model with three motors would make me believe there would be more ability to recover the energy quicker. A base model with only one motor wouldn't have the same resistance.

So my question for the OP would be how many motors are in your vehicles?

 

[ICUDoc]

That's an interesting possibility. Do you have any source of (reliable) info that would indicate that "reverse thrust" is being used or introduced by Tesla in a recent SW release?

Nope- was talking about RC cars, of which I have designed, built and raced many. Sorry, was not intending it to be a statement bout current Tesla mechanisms- although your question is an excellent one.

 

[Del Schier]

When driving my friend's model 3, I notice that his regen braking will bring him to a full stop which allows for easy one pedal driving in most cases. My S trails off regen around 6 mph to the point that the car will free wheel (for a considerable distance on level ground). I always have to switch to the traditional brakes to come to a full stop in traffic.

Creep is off and regen braking is set to standard. I don't see any other options that would let me come to a full stop using only regen. Am I missing something or are the cars just that different?

I wish my S would come to a complete shop. I just talked to someone with a 18 model 3 and his didn't stop but now it does after a software update. It isn't hardware because my S will come to a complete stop with autopilot or just the cruise control. I think they could care less about older model S owners.

 

[krsgio]

I wish my S would come to a complete shop. I just talked to someone with a 18 model 3 and his didn't stop but now it does after a software update. It isn't hardware because my S will come to a complete stop with autopilot or just the cruise control. I think they could care less about older model S owners.

the newer model S can come to a complete stop using full regen because they use the model 3 front motor. Older model S, prior to raven, don't have the hardware capable to regen to a full stop. autopilot and acc doesn't come to a complete stop using regen it uses the brakes...