I have a 2013 Volt. I live in Colorado and do a lot of driving where I'm coasting downhill. I often get going too fast and press the brake pedal to slow down. Do the mechanical brakes engage right away, or does it use the regen to slow the car down. If so, how can I tell exactly when the slowing down is caused by the regen and when mechanical brakes engage?
2013 When do mechanical brakes engage?
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If you tap the brake pedal regenerative braking will activate and can soak up around 50 kw of energy. (just watch your power meter on the heads up display to see how much) If you exceed the capacity of regenerative braking to slow down, and continue to press harder on the brakes, eventually your brake pads will engage to make up the difference in what you are getting, and what you are requesting. The other case, is when you come to a complete stop, just before you stop (at a very slow speed when regen braking is no longer effective), the brake pads will finally engage (pretty well engineered as the transition is almost seemless).
If you put it in L, it will also use regen braking to slow you down when you take your foot off the gas pedal. (again, watch your power meter on the heads up display to see how much power)
One final thought, is that the batteries can get too full to accept more power (notice battery SOC). If that happens, the vehicle will have to revert to brake pads. I think this is why mountain mode drains the pack down to about halfway, then holds it there. This way you have some battery pack head room to go up or down as needed in the mountains.
If you put it in L, it will also use regen braking to slow you down when you take your foot off the gas pedal. (again, watch your power meter on the heads up display to see how much power)
One final thought, is that the batteries can get too full to accept more power (notice battery SOC). If that happens, the vehicle will have to revert to brake pads. I think this is why mountain mode drains the pack down to about halfway, then holds it there. This way you have some battery pack head room to go up or down as needed in the mountains.
If I understand correctly, exactly what happens when you engage the brake pedal depends on how you engage it. In any car, there's a relationship between how hard you press the pedal and how soon the car will stop. In a conventional car, this is accomplished by the pressure you apply to the brake fluid. (That pressure is increased either as a direct mechanical result of your stepping on the brake pedal, or more usually in modern cars, via a power assist mechanism.) The greater the pressure in the brake fluid, the greater the pressure of the brake pads against the rotors, and the faster the deceleration. Therefore, stepping hard on the brake pedal results in maximum pressure and the most rapid stop.
In the Volt, light pressure leads to engagement of regen to slow the vehicle. Regen might be used for the vast majority of the slowing period except the final stop. There's a limit to how rapidly the car can decelerate from regen alone, so if you press hard enough, the brakes will be engaged to produce the level of deceleration that matches what the car "thinks" you want. If you press very hard, I think the car interprets this as you asking for an emergency stop and it applies the brakes immediately.
All this means that if you lightly press the brake pedal to slow down as you coast down a mountain, you are most likely going to slow down due to regen only (unless your battery is full). If you "slam on the brakes" because there are brake lights ahead, much of that rapid deceleration will be due to brake friction, not regen.
In the Volt, light pressure leads to engagement of regen to slow the vehicle. Regen might be used for the vast majority of the slowing period except the final stop. There's a limit to how rapidly the car can decelerate from regen alone, so if you press hard enough, the brakes will be engaged to produce the level of deceleration that matches what the car "thinks" you want. If you press very hard, I think the car interprets this as you asking for an emergency stop and it applies the brakes immediately.
All this means that if you lightly press the brake pedal to slow down as you coast down a mountain, you are most likely going to slow down due to regen only (unless your battery is full). If you "slam on the brakes" because there are brake lights ahead, much of that rapid deceleration will be due to brake friction, not regen.
I agree with the recommendation to drive in L. This will control your speed nicely with regen and no friction. Also watch your power meter, as this is a good indicator as well. There is also an Android app called "myGreenVolt" that can display exactly when the friction brakes are activated. If you brake early and gradually, you can avoid most use of the friction brakes, at least in moderate terrain.
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Wan't aware that there was no regen paddle in the 2013, when did they introduce it?
jcanoe is right, so far as the Volt is concerned, the regen paddle is exclusive to Gen 2
There's no way to tell. In Neutral and when the accelerator is lightly depressed in Drive, the car hits the pads immediately when you push the pedal at all. Under more normal conditions, there is significant additional braking by regeneration before it starts using the pads even in Low.
Without staring at OBDII instrumentation the entire time, there's no way I've ever seen to know where the transition starts.
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I think you mean Brake Pedal.
And I disagree.
Allow me to retell my tale of using instrumentation to show that no brake heat was made by using just the Brake Pedal alone, in D, to descend Pikes Peak.
At the Park Ranger Safety Stop on the way down everyone stops to have their brake discs read with an IR reader through the wheels.
My front brake discs were 70° on a 68° day. And that may have come from the final creeping along waiting in line!
My poor Volt pack got the biggest Fast Charge in its entire life!
I forget the miles gained but I was at 1 mile at the top and had a lot when leaving the park gate.
You don't have to fiddle-fart with driving '1 Pedal Style' or playing with herky-jerky regen paddles to get max regen in a Volt .
You can get max regen by driving just like a normal person.
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What did they have to say about that?
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I came down Mount Washington last year, gained 5KW of electricity. Didn't have an IR reader, just used my hand, the wheels were cold.I think you mean Brake Pedal.
And I disagree.
Allow me to retell my tale of using instrumentation to show that no brake heat was made by using just the Brake Pedal alone, in D, to descend Pikes Peak.
At the Park Ranger Safety Stop on the way down everyone stops to have their brake discs read with an IR reader through the wheels.
My front brake discs were 70° on a 68° day. And that may have come from the final creeping along waiting in line!
My poor Volt pack got the biggest Fast Charge in its entire life!
I forget the miles gained but I was at 1 mile at the top and had a lot when leaving the park gate.
You don't have to fiddle-fart with driving '1 Pedal Style' or playing with herky-jerky regen paddles to get max regen in a Volt .
You can get max regen by driving just like a normal person.
Seems to me what saghost is saying is that stepping on the brake pedal will use the friction brakes immediately if 1) the car is in Neutral, or 2) your other foot is pressing on the accelerator at the same time (regen cannot be created if MGB is functioning as a motor).I think you mean Brake Pedal.
And I disagree.
1) is correct, only friction braking is available when the Volt is in Neutral. 2) If you try and press the brake pedal and the accelerator pedal at the same time (requires both feet or one very flexible foot) you will find that the Volt will brake but the accelerator has no effect. It is not that MGB is functioning as a motor; MGB is not activated.
I meant exactly what I said. I did testing with OBDII instrumentation, and if the accelerator is lightly depressed while you hit the brake pedal, it bypasses the regen portion completely and goes straight to friction.I think you mean Brake Pedal.
And I disagree.
Allow me to retell my tale of using instrumentation to show that no brake heat was made by using just the Brake Pedal alone, in D, to descend Pikes Peak.
At the Park Ranger Safety Stop on the way down everyone stops to have their brake discs read with an IR reader through the wheels.
My front brake discs were 70° on a 68° day. And that may have come from the final creeping along waiting in line!
My poor Volt pack got the biggest Fast Charge in its entire life!
I forget the miles gained but I was at 1 mile at the top and had a lot when leaving the park gate.
You don't have to fiddle-fart with driving '1 Pedal Style' or playing with herky-jerky regen paddles to get max regen in a Volt .
You can get max regen by driving just like a normal person.
Folks that like the two footed driving method should especially take note.
The same thing happens if you hit the brake pedal while the gear selector is in Neutral.
Hitting both pedals in a single stroke I'm not positive what happens. My Volkswagens would zero the accelerator input when that happens - the only way to heel and toe the car was to hit the brakes first, then the accelerator, but that hasn't been true with other car's I've had.
If the accelerator is already depressed when you hit the brakes in a Volt, it happens as I described.
There is a setting in Mygreenvolt that generates a sound when friction brakes are applied. I have yet to hear it, either it's not working or my pads have never engaged the rotors within the threshold mygreenvolt requires. I generally drive in L and use the paddle to slow to maybe 5mph then apply the brake. In 5 months, 8,000km I can see no wear whatsoever on the rotors.
Somewhat related: What happens on low friction coefficient surfaces?
Re-gen is braking on the drive wheels only. What happens when the friction is less than the re-gen / braking capacity?
Does the traction control operate in re-gen to regulate the possible difference of traction of each drive wheel (i.e.: one wheel on snow, the other on merely wet pavement)?
Does the re-gen drop out if both driven wheels are slipping and revert to four wheel ABS?
How well does that transition from re-gen induced wheel slip to hydraulic ABS take place?
Should I simply forget about re-gen, shift to N, and then let the four wheel ABS regulate tire slip when the roads are snowy or icy?
Yes, this will be my first New England winter with my gen1 Volt.
Re-gen is braking on the drive wheels only. What happens when the friction is less than the re-gen / braking capacity?
Does the traction control operate in re-gen to regulate the possible difference of traction of each drive wheel (i.e.: one wheel on snow, the other on merely wet pavement)?
Does the re-gen drop out if both driven wheels are slipping and revert to four wheel ABS?
How well does that transition from re-gen induced wheel slip to hydraulic ABS take place?
Should I simply forget about re-gen, shift to N, and then let the four wheel ABS regulate tire slip when the roads are snowy or icy?
Yes, this will be my first New England winter with my gen1 Volt.
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