Don't know if this would be MY specific or not. And I guess the question may be specific Hold stopping mode. The manual says that the brakes are applied when stopped, but is that it? Maybe below 5mph? It doesn't seem to wait for a complete stop as when I am on a slight hill, the stopping is of course slower but it does eventually come to a complete stop without using the brake pedal.
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When is the brake applied during regen deceleration
- Thread starter spokey
- Start date
yes, single pedal driving is what I'm asking about. I figure it might make a difference if say it comes on under 5 mph, I shouldn't be creeping up to a light at 2-3 mph, but come up faster and let it stop. But if it's almost at standstill, I can do the creep.
Maybe the wrong way to drive, but in my ICE cars, it helps the gas mileage to get through the light at the highest speed without stopping ( I don't think many people have a lifetime mpg average in the 30s for a Subaru Outback).. I'm thinking the electric has the same 'gas guzzling from start' issues but the regen/braking functions could be changing how I should think about it.
Maybe the wrong way to drive, but in my ICE cars, it helps the gas mileage to get through the light at the highest speed without stopping ( I don't think many people have a lifetime mpg average in the 30s for a Subaru Outback).. I'm thinking the electric has the same 'gas guzzling from start' issues but the regen/braking functions could be changing how I should think about it.
Coasting for as long as possible when you must stop ahead is most efficient but it is generally incompatible with safe driving. When you apply the friction brakes or use the engine in a manual transmission ICE vehicle to slow the vehicle you loose all of your forward momentum to heat energy and can't recover any of this energy. Anytime you are converting mechanical energy to electrical energy, as with regenerative braking, there are conversion losses. Regenerative braking can typically recover up to ~70% of the energy from the moving vehicle. Regenerative braking can effectively slow the vehicle safely, keeping up with the flow of traffic, until the vehicle comes to a complete stop.
No friction braking is required in a Tesla when using one pedal driving. Tesla vehicles do not have blended braking; the Chevrolet Volt has true blended braking. With blended braking when you press on the brake pedal the vehicle will use regenerative braking to start to slow the vehicle. If you continue to press down on the brake pedal the vehicle will start applying the friction brakes in addition to the regenerative braking being active. In Tesla vehicles when you lift your foot from the accelerator pedal you are applying either full or low regenerative braking. The only way to coast in a Tesla vehicle without applying, at a minimum, low level regenerative braking would be to shift into neutral. I'm not sure if the Tesla will allow the driver to shift into neutral while the Tesla vehicle is moving at speed. In a Tesla vehicle the friction brakes are only applied when you press on the brake pedal or when you press the button on the end of the Tesla shift lever. Then the vehicle engages the rear brakes electronically to serve as the parking brake.
No friction braking is required in a Tesla when using one pedal driving. Tesla vehicles do not have blended braking; the Chevrolet Volt has true blended braking. With blended braking when you press on the brake pedal the vehicle will use regenerative braking to start to slow the vehicle. If you continue to press down on the brake pedal the vehicle will start applying the friction brakes in addition to the regenerative braking being active. In Tesla vehicles when you lift your foot from the accelerator pedal you are applying either full or low regenerative braking. The only way to coast in a Tesla vehicle without applying, at a minimum, low level regenerative braking would be to shift into neutral. I'm not sure if the Tesla will allow the driver to shift into neutral while the Tesla vehicle is moving at speed. In a Tesla vehicle the friction brakes are only applied when you press on the brake pedal or when you press the button on the end of the Tesla shift lever. Then the vehicle engages the rear brakes electronically to serve as the parking brake.
But if that were the case, the car would keep rolling
But if that were the case, it should keep rolling down hill unless I put my foot on the brake but it stops.
Are you saying that Park isn't a real lockup like a normal automatic trans? That it is just the rear brakes?
But if that were the case, it should keep rolling down hill unless I put my foot on the brake but it stops.
Are you saying that Park isn't a real lockup like a normal automatic trans? That it is just the rear brakes?
You would be correct, as it takes more energy to get moving from a standstill than it does to keep a moving object rolling.
If you are driving in Hold mode (in a Model 3 or Model Y) the electric motors will hold the vehicle in position once the vehicle stops. There is no transmission in the Tesla vehicles so there is no parking pawl to engage and lockup the transmission. The only thing holding the Tesla vehicle from rolling once you turn off the vehicle is the parking brake (the parking brake sets the rear brakes only.) It is possible, under some conditions, for the Tesla vehicle to lose its grip at the rear and start sliding on snow or ice covered parking space or driveway when parked on a slope. This happens when the weight of the vehicle melts the snow under the rear tires, turns the snow to ice. Once the rear tires lose their grip on the ice formed under the rear tires the vehicle will start sliding whichever direction is down hill. For this reason you should never park a Tesla vehicle on a snow or ice covered hilly street or on a sloped driveway. If you park pointed down hill on a hilly street and turn the front wheels towards the curb this may stop the vehicle from continuing to slide if the rear wheels lose their grip on the snow and ice. Other than by impacting the curb the front wheels will not hold the vehicle back.
Detroit built rear wheel drive vehicles for decades, I don't recall any driver education training I received ever cautioning about parking Detroit iron on a snow covered hill or sloped driveway. I was taught to always turn the front wheels towards the curb (when parking, pointed down hill), in case the parking brake or parking pawl failed but never any special caution about the rear tires melting snow and losing grip on the resulting ice underneath the rear tires. Maybe it has to do with the weight of the vehicle. I'm hoping someone knows the answer.
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I park on a hill with the wheels turned. Don't know how or why I learned that.
Yeah, until I sold my '93 300zx in 2009,. I drove mostly rear wheel. Much easier to do doughnuts in the parking lot snow.
But Tesla could have engineered a parking pawl. Wouldn't need a transmission. Not sure how the drive works but a pin in a motor or shaft or even a wheel would do it. Maybe not necessary though
Yeah, until I sold my '93 300zx in 2009,. I drove mostly rear wheel. Much easier to do doughnuts in the parking lot snow.
But Tesla could have engineered a parking pawl. Wouldn't need a transmission. Not sure how the drive works but a pin in a motor or shaft or even a wheel would do it. Maybe not necessary though
Here is a video of a Tesla Performance Model 3 vehicle that had just been parked, the passengers had just started to exit the vehicle. While one passenger is still inside, one of the rear doors is still open the Model 3 starts sliding down the driveway. The driveway is just barely covered with what appears to be a coating of fresh snow.
In the comments the owner states that they "called the local Tesla service center and was told it would be as simple as adding the screw drives the rear calipers use and wiring them up. Why this isn't standard I don't know."
I have not read that this fix exists anywhere else.
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If this engineering change were applied it appears that shifting to park would initiate both the front and rear brake calipers to clamp the rotors. Although there would still be the potential for both front and rear wheels to lose their grip at the same time having double number of immobilized wheels, even if the tire grip was compromised by being parked on a slip and slide surface is better than just relying on the grip of the rear tires alone to hold the vehicle from sliding. Does anyone know if the Model Y has the screw drives for the brake calipers on both the front and rear brakes?
SlyWombat
Member
Yes, you can. I used to use this back when I had range anxiety with hilly back country roads, coast down the hill and once you are up the other side re-engage. Also note that pressing the accelerator slightly so you balance the regen down to zero is pretty much the same effect. Now there are chargers everywhere
Does anyone know when the brake lights are activated with one pedal driving? I have begun to better understand how to feather the accelerator but curious what the experience is for the drivers behind me. I hate to be “that guy” that appears to brake at everything. I have only noticed the brake lights on while in hold at a traffic light at night on the screen
If this is similar to how the Gen2 Chevrolet Volt handles regenerative braking the brakes lights will automatically come on when a specific G-force threshold is reached while decelerating.
This should happen anytime you back off the accelerator whether your driving mode is set for creep, roll or hold.
This should happen anytime you back off the accelerator whether your driving mode is set for creep, roll or hold.
LNL_HUTZ
Member
The screen will show you the brake lights any time they are actually on. It may be difficult to see, but that's probably the best way to tell.
There are 3 levels of deceleration and resulting brake light illumination defined by law:
1) Some deceleration is minimal to the point that a brake light is not allowed.
2) There's a window of deceleration where a brake light is optional.
3) Finally, there's strong enough deceleration that a brake light is required.
I found a reference for 0.09g deceleration being a threshold but not sure if this is for level 2 or level 3.
1) Some deceleration is minimal to the point that a brake light is not allowed.
2) There's a window of deceleration where a brake light is optional.
3) Finally, there's strong enough deceleration that a brake light is required.
I found a reference for 0.09g deceleration being a threshold but not sure if this is for level 2 or level 3.
My experience is that it takes fairly heavy regen braking for the lights to come on. Harder deceleration than I use on the Camry to get it into it's regen zone as I'm lightly braking coming up to a light. I do have a hard time seeing the MY light so my sense could be off. But I tend to feel that I'd be happier if it came on a little earlier than it does.
I'm not sure about when you're coming to a stop but it seems to come on despite lack of g force before you actually fully stop.
I'm not sure about when you're coming to a stop but it seems to come on despite lack of g force before you actually fully stop.
This is my experience as well, I was a little uncomfortable with when my old Chevy Bolt brake lights would trigger, but these are definitely even later and make me nervous enough to occasionally tap the brake pedal if someone is behind me.
