Yaris Hybrid brake lights

[Mick F]

Yaris Hybrid going down a steep hill with gear selector in B ............... and not using the brakes.

As the car is effectively being braked, do the brake lights come on?

 

Thanks, Mick.

[FROSTYBALLS]

Doubt it.

Surely the same with any car using a low gear when going downhill.

[Mick F]

That makes complete sense.

I feel stupid even asking the question! 

Thanks, Mick.

[Gerg]

Not a stupid question at all.

Some years ago I tested an BMW I3 (electric), and the normal deceleration when lifting right off the throttle is very considerable, more than any conventional car. I asked the salesman if the brake lights would be operating when this happened, he said they would.

These chappies on the Speakev forum confirm it.

https://speakev.com/threads/extra-brake-light-to-show-regen-deceleration.15282/

I think there are manufacturer design regulations that enforce brake light operation beyond a defined deceleration threshold.

HTH.

[Mick F]

Well ........... it looks like an experiment is in order then.  What I need, is for someone to follow behind me coming down a hill perhaps?  Maybe Mrs Mick F could run behind. 

Another question though, is that if the car is stationary but in Gear B, could I get out and see if the brake lights are on, or is that scenario pointless because it isn't a dynamic situation with the car actually moving and being "braked"?

Mick.

[Gerg]

With the car stationary in 'B', I don't think the brake lights would be on.

In that link by way of comparison, someone mentions that the 'regen./overrun' is too lightweight to need trigger a brake light on a Nissan Leaf, (and that it doesn't on that car).

I would guess that the brake light doesn't operate on the move when using the 'B' mode, it would be interesting to know for certain though.

Approximately how fast can your wife run? Does she have any hi-viz clothing?

If you put some adhesive tape or paper partly across the high-level brake light, but so it was also visible in the rear view mirror, then it should be obvious if it's lighting once it gets dark outside.

[Mick F]

The answer is categorically NO, the brake lights do not come on in B.

We came home after dark yesterday evening and as we live on a narrow and steep lane, I could see the brightness of the brake lights through the rear-view mirrors. Selecting B alone didn't put the brake lights on, but pressing the brake pedal did of course.

I wonder why I didn't try that before.

Mick.

[YarisHybrid2016]

No.

I would like to know if the brake lights come on when cruise is braking downhill... 😂😂

[Mick F]

On 03/10/2017 at 12:54 AM, YarisHybrid2016 said:

No.

I would like to know if the brake lights come on when cruise is braking downhill... 😂😂

I have had a try with cruise control, and I'm not sure that it's required on a UK motorway as the speed varies so much with traffic, but I have found it useful in 30 or 40 mph limits to keep at the correct speed.

This leads me onto the brake lights issue in cruise.

Living in Cornwall, we have hills!  One of them near here is a 15% downhill for maybe a mile and it's a 30mph limit on the approach as well as down the hill.  I engaged CC ok and tried coming down the hill, but the CC wouldn't keep the car at 30mph, so I had to brake, so the CC disengaged of course.

Therefore, the brakes aren't operated automatically on downhills.  The car can only be slowed using engine braking.

Regards,

Mick.

[Mike J.]

6 hours ago, Mick F said:

Living in Cornwall, we have hills!  One of them near here is a 15% downhill for maybe a mile and it's a 30mph limit on the approach as well as down the hill.  I engaged CC ok and tried coming down the hill, but the CC wouldn't keep the car at 30mph, so I had to brake, so the CC disengaged of course.

Therefore, the brakes aren't operated automatically on downhills.  The car can only be slowed using engine braking.

There was never an issue regarding automatic brake use via cruise control - it doesn't happen. What does happen is that the regenerative 'braking' charges up the Battery. When the Battery is full, regenerative braking stops - fully electric cars have the same 'problem'. Our car has the bonus of B mode which brings in the petrol engine to give true 'engine braking' if you have a very long descent.

To check out on your hill, arrive at the top with an 'empty' Battery and confirm it keeps 30 mph using CC until the battery is full (not in B mode). To check out full regen, you need a hill that has 30 mph set someway down - set CC to 30 mph, disengage CC, enter the hill at the higher speed limit and resume the CC as you near the 30 mph limit and watch the power display as it fights to get to 30mph - it is at this point that the brake lights may come on - full regen.

[Mick F]

That sounds like a good experiment!

Not sure if the Battery was full or otherwise, but generally it tends not to be.  Usually a couple of cells short of the eight. I shall try again and keep the correct display showing.

Was on the A30 today coming back from Exeter.  Theres some long uphills and some long downhills near the Okehampton area,  and I was in CC for a while to see how it went.  At no time did it deviate from the set speed, but the down gradients aren't severe .................. so I'll try again locally.

Mick.

[YarisHybrid2016]

Cruise most certainly brakes, but it is whether it puts the brake lights on when it does it (I don't know). I can't say I hear the relay for the brake lights operating when it does.

[Mike J.]

9 hours ago, YarisHybrid2016 said:

Cruise most certainly brakes, but it is whether it puts the brake lights on when it does it (I don't know). I can't say I hear the relay for the brake lights operating when it does.

Cruise does not use the braking system, only the regenerative system, to slow the car. One proof is that when the Battery is full, regen stops and the car speeds up on a descent.

[Mick F]

That's the way I see it too.

If the brakes came on even gently, the car wouldn't increase speed on a long steep descent.

I drove up to Bristol and back yesterday, and used the CC quite a bit.  I didn't think I'd like it or want it especially on a busy M5, but it was actually quite good!  I like the way you can tweak the speed in small increments to stay on station in the lane.  Sorry, I digress!

On the descents on the motorway and on the A30, the car kept to the set speed perfectly.  One or two the the descents on the A30 are quite steep for a dual carriageway main highway, but the car stayed at the set speed perfectly.

The difference is on 30mph A roads with steep and long descents.  That is the acid test, and one I will repeat plus keep an eye on the Battery charge level.

Mick.

[Mick F]

Had another go, and made sure the Battery wasn't fully charged.  There were three cells showing white.

The car still didn't hold back, and it felt very much like that it had no intention of holding back.

I found this in the handbook.  Note the final sentence.

Mick.

 

[Mike J.]

2 hours ago, Mick F said:

Had another go, and made sure the battery wasn't fully charged.  There were three cells showing white.

The car still didn't hold back, and it felt very much like that it had no intention of holding back.

Interesting, there is probably another limit and that is for regeneration. Not many hills in Suffolk for me to check.

[YarisHybrid2016]

Hmm. I definitely see regen braking by cruise here, up to the max regen limit!

I can understand if it needs more braking than max regen to hold speed, that it will accelerate, but it should at least still try.

[MatthewPatrick]

Hi, 

Just a quick question re. brake lights on new Yaris...

I noticed today that they don't turn on unless I'm pressing quite firmly on the brake pedal. It's a bit problematic in slow moving traffic, as pressing more firmly means the car brakes quite aggressively, but don't appear to turn on at all if I'm pressing it lightly. The car behind wouldn't then see I'm slowly braking. 

Has anyone else noticed this, and does this seem right? 

Thanks

[Mike J.]

My brake pedal is very sensitive - just need to brush it to get the lights on - also work with the ignition off!

[Mick F]

Ours is too.  Easily seen on the cars behind, and it only needs a gentle touch to bring them on.

Last car was a Clio, and they needed a good press to get the lights on.

Mick.

[YarisHybrid2016]

@MatthewPatrick: Do you have a hybrid or regular version? The hybrid brake pedal at least, is very light.

The brake lights are controlled by the computer, and I have found that they can go off even with some pressure on the brake pedal, but that is because the car is either stationary or accelerating.

[Mick F]

On 14/11/2017 at 9:09 PM, YarisHybrid2016 said:

The brake lights are controlled by the computer ..............

That's very interesting.  I'd have thought it was just a mechanical switch on the footbrake mechanism, or a switch controlled by the pressure in the brake hydraulics.

Mick.

[YarisHybrid2016]

2 hours ago, Mick F said:

That's very interesting.  I'd have thought it was just a mechanical switch on the footbrake mechanism, or a switch controlled by the pressure in the brake hydraulics.

Mick.

I notice it most when reversing down the drive. I hold the car on the footbrake to get ready to reverse, then lift off the brake slightly until the car starts rolling backwards.

The brake lights are on while the car is stationary, then they go off when the car starts to move, but then they come back on again, even though I have not braked harder. Note that I have not completely lifted off the brakes, either.

On my old car, the brake lights were on whenever I had my foot on the brakes. The Yaris definitely behaves slightly differently.

[MatthewPatrick]

Hi,

I have the hybrid version. The brakes themselves are responsive, even just a light touch slows the car a lot... just no brake lights!