sgt1372
Posts: 533
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Location: SF Bay Area

Re: Too much regen in D mode

Tue Aug 15, 2017 4:00 pm

HotPotato wrote:Operationally, that's no different than coasting in neutral with a manual transmission and popping back into gear if you need acceleration or engine braking. Easier, even: no clutch!


This is actually illegal to do in CA.

It originated in the days of non-synchchomesh transmissions when commercial truck drivers would do that b4 stopping and then couldn't get back into gear until they completely stopped.

Sometimes their brakes failed b4 they could do that. So they adopted a vehical code violation against it

Not so much an issue now w/synchromesh but the vehicle code violation for doing it is still on the books.

Think it just applies to manual trannys but you could have problems getting back into gear w/an auto.

Generally NOT an advisable thing to do while moving, violation or not.
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GetOffYourGas
Posts: 1158
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Location: Syracuse, NY

Re: Too much regen in D mode

Tue Aug 15, 2017 5:59 pm

I agree with the OP. Or at least inasmuch as one should be able to turn it off. I love the eGolf's programability - the driver selects as much or as little regen as desired.
~Brian

EV Fleet:
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dandrewk
Posts: 239
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Re: Too much regen in D mode

Tue Aug 15, 2017 6:57 pm

The Bolt is a small car, but it is very heavy due to those batteries. It takes a lot of stopping power to slow/stop this vehicle, so having some level of regen or transmission slowing is a very good thing.

I'd hate for some Bolt driver, in a quest to increase his/her efficiency, coast downhill from the I5 Grapevine into the LA suburbs in "N", only to find that using 100% friction brakes has caused them to overheat. Ever try and use overheated brakes to slow/stop a car? Get ready to scream "WTF??!!"...

devbolt
Posts: 466
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Re: Too much regen in D mode

Tue Aug 15, 2017 8:37 pm

GetOffYourGas wrote:I agree with the OP. Or at least inasmuch as one should be able to turn it off. I love the eGolf's programability - the driver selects as much or as little regen as desired.


And in the Bolt, the driver has that capability, too. It's called L mode and feathering the accelerator pedal. My wife figured it out pretty quickly when I showed it it to her. You can do the same in D mode, just less regen, and maybe a bit more pedal travel needed.

redpoint5
Posts: 76
Joined: Tue Apr 04, 2017 5:17 am

Re: Too much regen in D mode

Tue Aug 15, 2017 9:06 pm

dandrewk wrote:The Bolt is a small car, but it is very heavy due to those batteries. It takes a lot of stopping power to slow/stop this vehicle, so having some level of regen or transmission slowing is a very good thing.

I'd hate for some Bolt driver, in a quest to increase his/her efficiency, coast downhill from the I5 Grapevine into the LA suburbs in "N", only to find that using 100% friction brakes has caused them to overheat. Ever try and use overheated brakes to slow/stop a car? Get ready to scream "WTF??!!"...


We're not talking about riding the brakes down the grapevine in N, we're talking about having a true coast mode. If the car had a true coast mode, there would never be a reason to manually shift into N.

The brakes are engineered appropriately to stop the vehicle regardless of regen.

Imagining a false scenario to justify your opinion that people shouldn't have the option to coast is absurd. I prefer my brake pedal to decelerate the vehicle, the accelerator pedal to provide propulsive power, and the absence of any input to observe Newton's first law of motion.
Last edited by redpoint5 on Wed Aug 16, 2017 4:35 am, edited 1 time in total.

GetOffYourGas
Posts: 1158
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Re: Too much regen in D mode

Tue Aug 15, 2017 9:10 pm

devbolt wrote:
GetOffYourGas wrote:I agree with the OP. Or at least inasmuch as one should be able to turn it off. I love the eGolf's programability - the driver selects as much or as little regen as desired.


And in the Bolt, the driver has that capability, too. It's called L mode and feathering the accelerator pedal. My wife figured it out pretty quickly when I showed it it to her. You can do the same in D mode, just less regen, and maybe a bit more pedal travel needed.


Yes and no. Feathering the accelerator is NOT the same thing as having a true "coasting" mode. It's the same result in terms of the car driving, but requires far different input from the driver.

I don't understand why people are so afraid of have this as an option. Not even the default option. Just an option.
~Brian

EV Fleet:
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GetOffYourGas
Posts: 1158
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Re: Too much regen in D mode

Tue Aug 15, 2017 9:12 pm

redpoint5 wrote:We're not talking about riding the brakes down the grapevine in N, we're talking about having a true coast mode.


This. In this mode, there is no reason not to blend regen with friction brakes when the driver presses the brake pedal.
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
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2015 C-Max Energi (302A package)
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PV1
Posts: 38
Joined: Mon Jul 31, 2017 8:11 pm

Re: Too much regen in D mode

Wed Aug 16, 2017 1:32 pm

dandrewk wrote:The Bolt is a small car, but it is very heavy due to those batteries. It takes a lot of stopping power to slow/stop this vehicle, so having some level of regen or transmission slowing is a very good thing.

I'd hate for some Bolt driver, in a quest to increase his/her efficiency, coast downhill from the I5 Grapevine into the LA suburbs in "N", only to find that using 100% friction brakes has caused them to overheat. Ever try and use overheated brakes to slow/stop a car? Get ready to scream "WTF??!!"...

Umm, why would anyone use friction brakes while purposely shifting into Neutral in the Bolt? Drop it back into Drive/Low if you need to slow down. Using Neutral is only to shut off regen for coasting, not bypass the motor and rely on friction brakes (which would be way more wasteful than the 13 kW of regen induced in Drive mode).

Folks have done hundreds of thousands of miles in EVs and coast in Neutral. I don't think anyone's overheated brakes.
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sparkyps
Posts: 86
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Re: Too much regen in D mode

Wed Aug 16, 2017 2:02 pm

I have zero interest in the added complexity of a "coast mode"

I rarely use the brake pedal and can accelerate, coast and slow down exactly like I want to using just the rightmost pedal and have instant responsiveness (faster/slower) without any complexities like switching in/out of a coast mode.

I have a stick shift car too and I simply don't drive the Bolt like I drive the stick shift. I also have a car with an automatic transmission and I would never put it in neutral while driving. That manual transmission cars are routinely taken out of gear is no reason to think that's how we should drive an EV.

I don't coast down hills either, I pick a speed and regen maintains that speed for me. Utterly unlike driving with a manual or automatic and using a combination of engine braking and brakes to keep my speed from becoming excessive. Driving down hill in an EV is a pleasure, I get to the bottom and likely haven't used my physical brakes once.

redpoint5
Posts: 76
Joined: Tue Apr 04, 2017 5:17 am

Re: Too much regen in D mode

Wed Aug 16, 2017 3:24 pm

sparkyps wrote:I have zero interest in the added complexity of a "coast mode"

I rarely use the brake pedal and can accelerate, coast and slow down exactly like I want to using just the rightmost pedal and have instant responsiveness (faster/slower) without any complexities like switching in/out of a coast mode.

I have a stick shift car too and I simply don't drive the Bolt like I drive the stick shift. I also have a car with an automatic transmission and I would never put it in neutral while driving. That manual transmission cars are routinely taken out of gear is no reason to think that's how we should drive an EV.

I don't coast down hills either, I pick a speed and regen maintains that speed for me. Utterly unlike driving with a manual or automatic and using a combination of engine braking and brakes to keep my speed from becoming excessive.


There is no added complexity of coast mode. It's simply programming each pedal to do 1 function only; stop or go.

Again, we're not talking about constantly shifting between modes, using N, or riding the friction brakes. If the car had an optional coast mode, I would stay in that mode forever, never having to use N, and using the friction brakes as rarely as everyone else.

The car would still regen going downhill while the cruise control is on. Coast mode would behave just like the other modes, except more efficient for those few people interested in maximizing range or efficiency.

Sure, most people aren't interested in efficiency or paying attention to how they drive. That's why the mode would be optional.

Really, these arguments that "I personally don't care about efficient driving techniques" is not a very compelling reason to be against the option. It's the same as me saying "I never use rinse mode on my dishwasher, therefore nobody should have the option".

...and you might not coast in neutral in your automatic, but I do.

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