regen and brake lights

[Andyw2100]

My comment was to provide a solution to the opening question - something which no one else seems to have answered in the past 37 posts !!!

Yes, so you did in fact answer the part about how with regen set to low, only the brake pedal activates the brake lights.

I haven't tested this myself, but I'm wondering if this is really how things work on US cars. I'd be surprised if it was. It would seem you'd still want brake lights when max regen is kicking in, even if the max regen is limited to 30, or whatever it is when the regen setting is set to low.

As for driving manners over here, you don’t pull out to overtake someone doing 60 on a motorway and then immediately appear to be slamming on the brakes once in front of them when the road ahead is clear and you're merely resuming a cruising speed of around 85. I personally really don’t like the sensitivity of the soft brake light that seems to flicker on with a mere -15kw of braking effect. I only want it to come on when I actually press the brake pedal. Each to their own I guess

I understand what you're saying. I think as electric vehicles become more common place people will become more accustomed to seeing brake lights when cars are not slowing down that significantly. As has been pointed out, drivers already have to be alert for people using engine braking, who slow down with no indication of doing so from brake lights. Being alert for people whose brake lights may come on when they are only slowing down a little seems like the safer end of the other end of that spectrum.

 

[Cyclone]

I've been trying to find NTHSA studies on rear-end in "no light" scenarios, like a manual tranny downshift. Lots (and I mean TONS) of studies showing how rear-end are most common, proposing various enhanced lighting mandates, including flashing, based solely on G of de-cel, etc, etc.

So far, no actual stats that clearly separate light v no-light rear end... but like I say, much indirect evidence that slowing with no lights showing is bad.

Sadly I have no studies to point you to, but I have driven through areas that specifically had road signs that said "No Engine Braking - Use Brake Lights". I guess some towns and cities have thought about this along these lines.

 

[brianman]

My P85D running 6.1.179 does NOT do that. I see no indication of any of the lights on that screen.

Try the Controls screen (where you can turn on/off DRLs and such).

 

[jerry33]

s for driving manners over here, you don’t pull out to overtake someone doing 60 on a motorway and then immediately appear to be slamming on the brakes once in front of them when the road ahead is clear and you're merely resuming a cruising speed of around 85. I personally really don’t like the sensitivity of the soft brake light that seems to flicker on with a mere -15kw of braking effect. I only want it to come on when I actually press the brake pedal. Each to their own I guess

Almost every ICE driver that passes me puts their brakes on right after they pass and get in the lane. I don't see how the way the Model S works is any different. I guess the brake lights work differently over here (N.A.) because lifting your foot off a bit to slow down doesn't turn them on. Only if you do some serious regenning does the light come on. Use the accelerator pedal in analogue mode rather than binary mode.

 

[brianman]

Use the accelerator pedal in analogue mode rather than binary mode.

Heh.

 

[Blu Zap]

"One pedal" driving does take some getting used to especially when you get back in the ICE! As has been mentioned the brake/deceleration lights come on as a percentage of speed deceleration. Another way to see when the brake lights come on during the day is with the charging screen brought up as well as the "T" screen. An ICE with manual transmission can present the same slowing down issue with no brake lights by downshifting. So this is not unique to EVs.

 

[billarnett]

Try the Controls screen (where you can turn on/off DRLs and such).

The front lights show up there but not the rear ones. Am I really missing something here? Has there been a change from some earlier firmware version ? Or are we all just repeating the same unverified assertion?

 

[andrewket]

The front lights show up there but not the rear ones. Am I really missing something here? Has there been a change from some earlier firmware version ? Or are we all just repeating the same unverified assertion?

I'm traveling and away from my car at the moment so I can't find it presently, but this was certainly possible in previous firmware versions. When the model S first came out and we were trying to understand how much regen caused the brake lights to come on, this was the solution. This was after one person installed an LED inside the car connected to the middle brake light so you could see it via the rear view mirror. :/

 

[jerry33]

The front lights show up there but not the rear ones. Am I really missing something here? Has there been a change from some earlier firmware version ? Or are we all just repeating the same unverified assertion?

There could have been a change. I never have that screen on unless I'm actually setting something.

I'm still trying to understand the problem here. As far as I can tell, by looking what happens at night through the camera, the brake lights come on when you regenerate hard or press the brake pedal. If it was an automatic transmission car they would come on more often because you'd be touching the brake pedal a lot more.

 

[MassModel3]

If you hit the battery icon while driving to bring up the charge screen, it shows a side view of your car. If your brake lights come on, you'll see the brake light in the displayed car also come on. My firmware is 6.1(2.2.200).

 

[Brass Guy]

The charge screen (battery icon) is the right answer. IIRC, with earlier releases (before mine which had v5.0 on delivery) the image brought up by the T showed the lights realtime but that feature went away. It remains functional on the charge screen display. On that screen you can see the left brake light and the high center brake light.

I think the issue with the brake light is the driver. If you accelerate rapidly to pass someone, don't let off the accelerator so much. It takes a little practice, but you can release the accelerator to the point of maintaining speed. If you let off too much, you will be slowing down. Expect brake lights.
This reminds me of the computer acronym, PIBKAC.

 

[Danal]

Verified, charging screen shows ALL lights on Port side of vehicle, with 6.1 and 6.2 software. It is rather subtle if there is a lot of ambient light. I find the HCMSL (High Center Mount Stop Light), that is the "LED Strip" at the top of the glass, to be most detectable on this screen.

 

[Pilot_51]

My experience/opinion seems to be the opposite of most: I don't think the brake lights come on enough. Over roughly 30 MPH, it's fine. Lower than that, the regen deceleration is stronger even though the regen power isn't as high, yet the brake lights don't come on at the point where I feel the deceleration should be indicated to the driver behind me. Though, I should note that I've only seen the brake light in the rear camera a handful of times and haven't done any real tests. Earlier on, after I noticed that the brake lights didn't come on when I thought they should, I would press the brake pedal a bit to make sure of it, causing me to slow down more aggressively. I stopped doing that since I figured it was worse and I should trust that Tesla knows what they're doing.

 

[billarnett]

Verified, charging screen shows ALL lights on Port side of vehicle, with 6.1 and 6.2 software. It is rather subtle if there is a lot of ambient light. I find the HCMSL (High Center Mount Stop Light), that is the "LED Strip" at the top of the glass, to be most detectable on this screen.

Thanks! But boy, that's a pretty subtle indication. I'll stick with the camera at night. Not that I really care, IMHO, Tesla has the algorithm about right. I stopped worrying about this years ago the first week I had my Roadster.

 

[Al Sherman]

When I first got the car I was a little worried about this too. I beat it to death testing it at night with the backup camera. I found the lights to come on and go off at pretty much the perfect time. I haven't worried since and have never had a negative experience with other drivers. Just my 2 cents. YMMV.

 

[Doogue]

errr, yeah … I wasn’t trying to be 'drastic' or 'please' other drivers; yes I am aware that 'low' regen marginally lowers regen efficiency; and no I am not in the slightest bit bothered about it ..

My comment was to provide a solution to the opening question - something which no one else seems to have answered in the past 37 posts !!!

As for driving manners over here, you don’t pull out to overtake someone doing 60 on a motorway and then immediately appear to be slamming on the brakes once in front of them when the road ahead is clear and you're merely resuming a cruising speed of around 85. I personally really don’t like the sensitivity of the soft brake light that seems to flicker on with a mere -15kw of braking effect. I only want it to come on when I actually press the brake pedal. Each to their own I guess

I am completely with you PV4EV!!! I am thinking that most people who have replied to this thread came from driving automatic ICE cars and have little to no experience with a manual transmission or never learned to drive them properly.

Let me put this a different way: It is hard not to look like an absolutely rookie when driving a Tesla, given the way the brake lights come on so easily when you lift your foot off the accelerator. The vast majority of the world learned to drive on either a manual or automatic ICE car, neither of which requires one to feather the accelerator to avoid brake lights coming on. Put another way, in the cars that we've all learned to drive when you let off the accelerator the brake lights never come on. Driving behind a tesla driver is similar to driving behind a NYC cabbie - brake lights going on and off all the time. If you drove a manual transmission this way, short of race car drivers, you would look like an absolute tool that just learned to drive. Using the gears to slow your vehicle is the correct way to drive a manual transmission and in doing so, you need to engage the brakes much less often.

Almost all of the manual transmission cars, heck even tiptronic equipped automatics in a sport mode, have a very similar initial reduction of speed when you let off the accelerator, due to the gearing, and no brakes come on.... ever. Admittedly, Tesla's reduction in speed is slightly more dramatic initially and substantially more so the longer you coast, but do we really need to blare lights each time we let off the accelerator? I don't think so.

I love the regenerative braking concept and absolutely want to take advantage of it, but I think there should be some middle ground - like a "Medium" regen setting - so that one can get some of the energy back, but not signal braking each time you slow down slightly. Or, perhaps allow for full regen, but have a 1 second delay on the brake lights when one lets off the accelerator to indicate, you know, that you are actually stopping. So, to use PV4EV's example, pass someone and get in the right lane, lights would only come on if you stayed off the accelerator for more then 1 second. Otherwise, you're alerting the person behind you, odds in they're in an ICE car, that you are stopping and therefore they should now start hitting the brakes...