Tesla owners: How strong is regenerative braking?

[Chris L]

Low/Normal/High options would be good. There may be hardware limitations as the A/C output from the motor has to be rectified to D/C to charge the battery — not a problem to do that, but they have to decide to do it. I think they (and other EV manufacturers) do not want EV drivers to get so accustomed to using regen for all their braking, that someone causes an accident because they forgot to use the more powerful friction brakes, and then either of the parties sues Tesla for encouraging reliance on the magnetic brakes. And the stronger you make the magnetic brakes, the less drivers will think to use the friction brakes. There needs to be more discussion and education, and industry-wide standards so the operation of regen works the same for all EVs.

 

[animorph]

Compared to the BMW i3, the regen braking on the Model S is not as strong. I actually prefer the regen braking on the i3 because it's easier to do 1-pedal driving. I wish the Model S had a more aggressive regen option beyond the normal/low options.

Stronger regen gives you the option of coming to a stop in a shorter distance, but at a cost in energy usage. Just like coasting is more energy efficient than using regen. Still better than friction braking alone of course.

The current Model X standard regen setting pretty well matches the deceleration I had in my Porsche with aggressive downshifting and engine braking only. I'm used to that and it works fine for me. I can come to a near stop with the desired spacing to the car in front, in a distance that feels natural to me, using nearly all regen without having to start way early (coasting) or late (more braking).

If you are used to running up to the car ahead of you fairly quickly and hitting the brakes for a short distance, then more regen would be beneficial. For me, with stronger regen I'd probably feather the accelerator a bit to reduce deceleration and keep things comfortable.

 

[animorph]

Low/Normal/High options would be good. There may be hardware limitations as the A/C output from the motor has to be rectified to D/C to charge the battery — not a problem to do that, but they have to decide to do it. I think they (and other EV manufacturers) do not want EV drivers to get so accustomed to using regen for all their braking, that someone causes an accident because they forgot to use the more powerful friction brakes, and then either of the parties sues Tesla for encouraging reliance on the magnetic brakes. And the stronger you make the magnetic brakes, the less drivers will think to use the friction brakes. There needs to be more discussion and education, and industry-wide standards so the operation of regen works the same for all EVs.

Standard regen gives something like 70 kW I believe. That's peak Supercharging rate for a few unlucky Tesla owners, and already above the final Supercharger taper rates at higher states of charge. Stronger regen might only be available below 50% state of charge, say, where it is still safe to charge the battery at greater than 70 kW. Might be more trouble than it's worth, since it would vary with charge state. Since regen not a continuous charge over a relatively long period, maybe it's OK that it exceeds the Supercharger taper for a short period, but the electronics definitely wouldn't want to handle more than peak charging power.

A smaller car can get more deceleration out of that 70 kW, so maybe Model 3 will have a stronger regen feel than the S or X.

 

[calisnow]

I own a non-tesla EV which applies regenerative braking via the brake pedal. I understand tesla only applies friction brakes via brake pedal. How much deceleration do you experience by just lifting the accelerator?

Strong enough that I expect my brake pads and rotors to last a couple hundred thousand miles at least.

 

[EchoDelta]

Low/Normal/High options would be good.
There needs to be more discussion and education, and industry-wide standards so the operation of regen works the same for all EVs.

Hmm I disagree- regen strength options are good but I think the optimal I've experienced is in the on-by-default radar -based adaptive regen strength of the Mercedes B-class.
I feels as a "lighter" baseline setting than the default on the X but it automatically detects cars slowing down and increases regen to match speed or eventually almost stop. Note this is at any speed, anywhere and without needing to "turn it on" like TACC. It starts very proactively and more than once I realized the car in front of me was starting to stop not because of their brake lights but because my own car slowed down a bit.
With this feature you both drive safer and increase efficiency- as you can coast by default with zero energy input (not that I care really, it's a game kind of like trying to drive at an exact speed) but then regen happens more gradually in scenarios for traffic.

And I profoundly disagree with the regen experience standardization. We are in a great period to let manufacturers re-imagine and experiment with new approaches to driving and riding.
Limiting everyones freedom because of the risk of someone suing sounds like a huge step back.

 

[SageBrush]

Regen mapping is a religious argument: a preference argued with a passion
The 60 kW of max regen is NICE(tm), and the rest of the discussion will go on forever.

 

[insaneoctane]

Does the software update capability of Tesla's have the flexibility to adjust the brake lights indicator to light up anytime the regenerative braking exceeds, say, 5kW?

 

[CameronB]

Brake lights are automatically activated during most (all?) regen. So shows the binacle display of the car icon. High regen is great and i expect brakes to last a long time since they only need to be used that last 4 or 5 mph when the regen cuts out.

When your battery is full (range/trip charge) there is little to no regen available so you do have to get used to those cases where regen is weaker.

All of this has pretty much been covered earlier.

I did want to add that the regen is not nearly as strong on Teslas as on the Chevy Bolt. If you have driven that car, you know that with max regen settings plus the steering wheel paddles, you can really do "one pedal driving" more of the time. As I understand it, that's due to Chevy's use of a permanent rare earth magnet, which Tesla apparently does not use. I don't know this for a fact, but that's what I have read. But I have driven a Chevy Bolt and can definitely confirm the regen braking feels significantly more powerful compared to Tesla and in my surface street test drive, I was indeed able to pretty easily bring the Bolt to a complete stop without using the brakes at all.

 

[SageBrush]

I did want to add that the regen is not nearly as strong on Teslas as on the Chevy Bolt.

They are about the same power but the Bolt is a lighter car. The Model 3 will probably feel "Bolt like."

 

[Yggdrasill]

The brake lights are activated through deceleration. At high speeds the deceleration from regen isn't very great, so the brake lights don't activate. At lower speeds (~25 mph) it activates at something like 20 kW regen. (That's on a 2500 kg Model X, though. The power will sacale with mass.) If I don't want the brake lights to activate, I can start out at full regen, and then use less and less regen as the speed is reduced. At like 10-15 mph I can release the accelerator pedal fully and the car won't be able to use full regen, and the brake light won't activate.

 

[Thorbjorn]

It's very nice and lets you drive one pedal most of the time.
You'll get used to it very quickly.

It's horrible to drive any other car after. It's the feature i miss the most when i drive other cars.

 

[wdolson]

Stupid Question : Has anyone ever hit the P button by accident while driving? I have not had any vehicle with a steering column mounted shifter, so I wonder.

I once hit it by accident when I was pulling to a stop and going about 1-2 mph. The car stopped very suddenly, but that was very low speed. I could see it locked out at speed, but what do you do in a runaway car situation? In an ICE, you can apply the emergency brake and if that doesn't do the job, you could shut off the engine, or as a last resort you can sacrifice the transmission and throw it into Park. I don't know what you could do in that sort of situation in a Tesla.

 

[gregincal]

I once hit it by accident when I was pulling to a stop and going about 1-2 mph. The car stopped very suddenly, but that was very low speed. I could see it locked out at speed, but what do you do in a runaway car situation? In an ICE, you can apply the emergency brake and if that doesn't do the job, you could shut off the engine, or as a last resort you can sacrifice the transmission and throw it into Park. I don't know what you could do in that sort of situation in a Tesla.

It was mentioned in a post above, you keep holding down the park button and it will apply the emergency brake.

 

[Snerruc]

As far as I am concerned, Tesla regen is just about perfect. I don't see any point in complicating the process with selectable levels. Most people would ignore it, just like their video recorders blinked 12:00 like mine.

 

[wdolson]

It was mentioned in a post above, you keep holding down the park button and it will apply the emergency brake.

I missed that scanning the thread. Thanks.

 

[scottm]

I wouldn't mind if Tesla added some friction brake at the end of a long regen to actually halt the car... if you've stayed off the "go pedal" for the whole current regen cycle, intent is pretty clear at about 1 mph you want to stop. If you touch (re-apply force to) the go pedal anytime going below say 5 mph then all bets are off... the auto-stop feature takes a snooze for that regen cycle: the car will follow direction from the pedal and coast-out if you get off it.

However, options!! Don't force this on people:

Tesla has overloaded function buttons on the car before (like Range Mode, has multiple effects) so what if Tesla overloaded the "Creep Mode" button? When creep is ON, the car doesn't use friction brakes to halt a regen down to zero, and when creep is set to OFF it will use the friction brake. Seems this would be consistent for people who like their cars to slip forward at crawling speeds, and those that don't.

 

[eladts]

It's not so easy. You need to be pretty exact. I've seen Tesla Bjørn put it into neutral, which allows it to coast. That seems easier.

Driving in N is illegal in many jurisdictions. The reason for that is if you are gliding in N you cannot accelerate if you need to.

 

[Ace1]

Actually, in order to get regenerative braking, the car must be moving (motor turning). The motor in regenerative mode becomes a generator and at slow speeds, the braking effect greatly diminishes. Obviously, when the car is at rest there is no regeneration and the friction brake must be used to hold the car from moving.

 

[milleron]

Teslas are pretty much the least efficient EV out there. I expect the 3 to be a bit more efficient than the S, but it still won't touch the i3. It is still less than half the cost of a very fuel efficient EV, though, so my advice is to enjoy it.

Boourns, that's interesting. I've not seen a hierarchy of BEV efficiency. How is efficiency measured for comparison? MPGe on standardized tests? How much more energy efficient is an i3 than a Model S?

 

[Boourns]

MPGe is one way to do it. Based on MPGe a Model S is somewhere in the 89-104 range and the i3 is 124. The new Hyundai is actually the best. See here. The EPA fuel economy ratings also give the usage in kWh/100 miles, which is something a Tesla owner can make more sense of. The i3 is about 270 Wh/mi where as the S is above 300.

Since I wrote that post, though, there is some speculation about the 3 getting something like 237 Wh/mi, which would actually make it the most efficient See: Tesla accidentally reveals Model 3 efficiency hinting at impressive range and the thread here.