Regenerative Braking Behavior Poll

[Farzinfar]

@RAW84 and @RogerHScott:

The setting is on “standard” and not “low”. Everything else same as before update. I never fully charge the battery and the car is always preheated. Same route, same slope, everything the same but regen brakes less responsive and steep slope. I am puzzled!

 

[RAW84]

How would this work when regen is limited, or even non-existent, due to full charge, cold, etc.?

I suppose it would work the same way it does now (just not shutting off at 5mph). So if it can't regen (for whatever reason), it won't regen, but when it's available regen will continue until the car completely stops.

 

[Farzinfar]

I suppose it would work the same way it does now (just not shutting off at 5mph). So if it can't regen (for whatever reason), it won't regen, but when it's available regen will continue until the car completely stops.

The issue is without applying on acceleration pedal, on the downhill the car builds up speed and this was not the case before and it is not the case on the highway and high speed. Before the update on a downhill I had almost full -50 indication on the display and car was going down at a steady speed even slowing down slowly but it is building up the speed very quickly now. There is either a co-incident with the latest update and regen brake has some fault or there is a change in how regen brake works after upgrade.

 

[RAW84]

The issue is without applying on acceleration pedal, on the downhill the car builds up speed and this was not the case before and it is not the case on the highway and high speed. Before the update on a downhill I had almost full -50 indication on the display and car was going down at a steady speed even slowing down slowly but it is building up the speed very quickly now. There is either a co-incident with the latest update and regen brake has some fault or there is a change in how regen brake works after upgrade.

That post wasn't in reference to your issue.

But you note that prior to the update on a downhill you had almost full -50 indication on the display....does your car still indicate this after the update? Or is it saying there's a limitation?

 

[Helmuth]

They could use the regular brake for the last few yards to bring the car to a complete and gentle stop.
Like with AP or TACC enabled. IF you don’t push the accelerator nor the brake it’s likely you’ll come to a complete stop anyway!

 

[Farzinfar]

That post wasn't in reference to your issue.

But you note that prior to the update on a downhill you had almost full -50 indication on the display....does your car still indicate this after the update? Or is it saying there's a limitation?

Ok sorry I thought it was referenced to my issue. After update on downhill there is no regenerative brakes, no slowing down and no indication on the display. However after driving the car in highway and in high speed if I lift my foot from accelerater then regen brake works perfectly and slows down the car.

 

[RogerHScott]

I suppose it would work the same way it does now (just not shutting off at 5mph). So if it can't regen (for whatever reason), it won't regen, but when it's available regen will continue until the car completely stops.

So, kinda like a brake you can't rely on? Sounds great; sign me up!

 

[brkaus]

Can somebody share the benefits of having the car coast instead of coming to a complete stop?

Keeping the brake pedal in muscle memory as it is still required for more urgent stopping.

Unless regen is really dialed up, but then I feel like it would be harder to drive in a smooth manner.

 

[GatorGuy]

Ok sorry I thought it was referenced to my issue. After update on downhill there is no regenerative brakes, no slowing down and no indication on the display. However after driving the car in highway and in high speed if I lift my foot from accelerater then regen brake works perfectly and slows down the car.

Doesn't make sense for regen to simply not work on a hill. How would the vehicle even differentiate? So I would suspect something is wrong with your vehicle.

 

[Farzinfar]

That post wasn't in reference to your issue.

But you note that prior to the update on a downhill you had almost full -50 indication on the display....does your car still indicate this after the update? Or is it saying there's a limitation?

Ok sorry I thought it was referenced to my issue. After update on downhill there is no regenerative brakes, no slowing down and no indication on the display. However after driving the car in highway and in high speed if I lift my foot from accelerater then regen brake works perfectly and slows down the car.

 

[RAW84]

So, kinda like a brake you can't rely on? Sounds great; sign me up!

That's exactly what regen is now for speeds above 5 mph. \_(ツ)_/¯

I don't see why there's a problem letting the regen continue below 5 mph.

 

[RogerHScott]

That's exactly what regen is now for speeds above 5 mph. \_(ツ)_/¯

I don't see why there's a problem letting the regen continue below 5 mph.

No one is going to think of something that doesn't slow you below 5 mph as a "brake". Something which often functions as a brake will come to be thought of as a brake, even if it is not reliably so.

 

[RAW84]

No one is going to think of something that doesn't slow you below 5 mph as a "brake". Something which often functions as a brake will come to be thought of as a brake, even if it is not reliably so.

Why not? If it brakes you from 60 to 50 mph pretty aggressively, isn't that braking? I certainly think of it as a "brake"

We currently rely on regen braking to do this pretty regularly. And in those times when regen is limited and it's unable to "brake" as we are accustomed at 60 mph, we simply use the mechanical brake to slow down to 50 mph as quickly as we need it. It's neither hard nor dangerous. For some reason you are suggesting we'd be incapable of switching to mechanical braking when the car is going just 5 mph, tho, and I can't see why.

 

[RogerHScott]

Why not? If it brakes you from 60 to 50 mph pretty aggressively, isn't that braking? I certainly think of it as a "brake"

We currently rely on regen braking to do this pretty regularly. And in those times when regen is limited and it's unable to "brake" as we are accustomed at 60 mph, we simply use the mechanical brake to slow down to 50 mph as quickly as we need it. It's neither hard nor dangerous. For some reason you are suggesting we'd be incapable of switching to mechanical braking when the car is going just 5 mph, tho, and I can't see why.

All I'm saying is that it is human nature for form habits and when those habits rely on the unreliable bad things can happen. Maybe it's just the engineer in me, but when I have a choice between "might work" (stopping via unreliable regen on the accelerator pedal) and "does work" (stopping via optional regen on the brake pedal) I pick "does work" every time.

 

[jgs]

am I the only one who worries about using regenerative braking to its (current) full length?

Yes.

 

[GatorGuy]

All I'm saying is that it is human nature for form habits and when those habits rely on the unreliable bad things can happen. Maybe it's just the engineer in me, but when I have a choice between "might work" (stopping via unreliable regen on the accelerator pedal) and "does work" (stopping via optional regen on the brake pedal) I pick "does work" every time.

The great thing with the Tesla system it isn't one or the other. I lift off the accelerator and if it slows me enough then great. However, if I'm driving faster, then I use the brake. It is automatic muscle memory. And I've only been driving a Tesla for a few weeks.

But in all honestly I was used to the Tesla system by the end of my first test drive.

 

[BinaryField]

Yes.

What exactly is this supposed to mean, in response to my concerns about being concious of other drivers and avoiding a rear-end collision?

 

[SSonnentag]

I want it to be an option. I'd most likely use it.

 

[jgs]

What exactly is this supposed to mean, in response to my concerns about being concious of other drivers and avoiding a rear-end collision?

Well, it was a little snarktastic, but you did post a simple yes-or-no question so I answered it that way!

To elaborate, I've been using regen for stops for more than three years now, but for that matter I've driven pretty much that way for decades. Engine braking on a manual is much like regen. Actually regen is safer since it engages the brake lights, which engine braking doesn't. The reason for coasting in to a stop is the same in either case -- brakes throw away energy (so does engine braking, my former practice was coast into a stop when I could, engine or friction brakes when I must). I've never been in an accident or even near-miss or been honked at as a result. I suppose YMMV based on how aggressive drivers are in your area, although I would expect a more aggressive driver to also be quicker on the brakes -- they'd better be, otherwise they're not going to last very long on the road.

Better?

 

[RAW84]

All I'm saying is that it is human nature for form habits and when those habits rely on the unreliable bad things can happen. Maybe it's just the engineer in me, but when I have a choice between "might work" (stopping via unreliable regen on the accelerator pedal) and "does work" (stopping via optional regen on the brake pedal) I pick "does work" every time.

I understand your concern in general, but not in the context of what's being queried with this thread: having regen braking continue all the way down to 0 mph instead of the current 5 mph limit.

Currently, if I'm approaching a stop light, I lift my foot off of the accelerator in a fashion that tries to bring the car down to 5 mph right before I need to fully stop at which point I engage the mechanical brake. I'm not perfect so sometimes I undershoot, sometimes I overshoot. In either case I take corrective action (accelerate or mechanically brake) as needed. Regen won't suddenly become more limited in the middle of my braking sequence so I'll know when I begin braking whether regen is working leaving myself plenty of time to take corrective action. Moving it from 5 mph to 0 mph is simply moving the target.

Your concern seems to be more relevant to whether you should use regen braking at all since it can't relied upon to operate the same always. I still think it's fine because it's easy and intuitive enough to adapt on the fly, but for those that don't, they can simply reduce the regen and never rely on it.