Regenerative Braking Drive Modes Gimmicky?

[JoulesThief]

I honestly never figured out the usefulness of that gauge. If anything, it seems more gimmicky than the regenerative braking mode

(maybe it will be useful a few years after ownership)

Step deep into the throttle going up a steep grade, and you'll exceed the batteries discharge capacity, heat the battery up, and you can watch that power needle drop.... you are exceeding the batteries discharge capacity, battery gets hot, and the temp sensors reduce potential discharge rate of the batteries, for safety reasons... runaway battery temps and potential fires. Not very good for the battery chemistry and long term life for the battery either.

 

[bizzle]

.

 

[JoulesThief]

Have you actually done that or are you speculating?

Keep wondering if I've made that needle move. Not good for the battery. That gauge is basically a shunt that tells you instant amperage surge capacity of the battery.

 

[MysteryMan]

Hi all!

I am new to this forum and will be getting a VW e-Golf later this year and, so, I was reading with great interest all the comments about regenerative braking - I hadn't realised it would be so complex!!!!

Anyway, I saw the comment a few times about the need to control your right foot. However, I tend to use Cruise Control a lot and wonder what effect that has on efficient driving - does it make it easier or harder?

 

[JoulesThief]

Hi all!

I am new to this forum and will be getting a VW e-Golf later this year and, so, I was reading with great interest all the comments about regenerative braking - I hadn't realised it would be so complex!!!!

Anyway, I saw the comment a few times about the need to control your right foot. However, I tend to use Cruise Control a lot and wonder what effect that has on efficient driving - does it make it easier or harder?

Harder.

Cruise control is lazy, maximum efficiency will take work on your part to achieve the desired results. Your choice, whatever is right for you, under the circumstances. Going up and down over undulating terrain is what makes it inefficient.

Of course if you are on flat ground and want to set the cruise control for 45 to 50 mph, you might be surprised at the number of miles you can go on a single charge, if you never touch the brakes, and turn all the ancillary power sucking features off that provide creature comforts that either shorts and a tank top, or bundled up layered clothing, for winter temperatures provide. Provide yourself the same clothing, in season, that you would provide for yourself if riding a horse in the elements, in season, would require.

 

[japeters]

Of course using the brakes recharges the battery! All you have to do is look at the battery charging gauge when you use the brakes. The needle goes into the green area. It does not matter what mode you are using.

I am an Electrical Contractor but not an engineer.

 

[japeters]

"B" mode jack rabbit driving uses up some energy accelerating and stores some energy when decelerating as long as you stay in the green part of the dial. It's fun but not all the energy is reclaimed because of friction loss in the drive train and something called hysteresis witch means loss of electric electricity due to loss of magnetism.

My question is - If you do have to use the brakes hard enough to go past the green area and into the black mode will it use the back brakes more than the front brakes because the front brakes not only using the pads, but are slowing due to recharging at the same time they are using the pads.

Another question is - Do the brake lights come on when you are slowing using the be mode?

 

[JoulesThief]

"B" mode jack rabbit driving uses up some energy accelerating and stores some energy when decelerating as long as you stay in the green part of the dial. It's fun but not all the energy is reclaimed because of friction loss in the drive train and something called hysteresis witch means loss of electric electricity due to loss of magnetism.

My question is - If you do have to use the brakes hard enough to go past the green area and into the black mode will it use the back brakes more than the front brakes because the front brakes not only using the pads, but are slowing due to recharging at the same time they are using the pads.

Another question is - Do the brake lights come on when you are slowing using the be mode?

Brake lights come on in II, III and "B" mode.

 

[RonDawg]

My question is - If you do have to use the brakes hard enough to go past the green area and into the black mode will it use the back brakes more than the front brakes because the front brakes not only using the pads, but are slowing due to recharging at the same time they are using the pads.

I've never seen the power/regen meter go into "the black." Even with hard braking it only goes as far as the left/lower edge of the regen zone (the 9 o'clock position). If the battery is full, it will only move a very small amount into the regen zone even with hard braking.

 

[MysteryMan]

A couple of related questions....

Is there any difference, in terms of Regen, between 'normal' braking and the D1/D2/D3 modes? Both move the needle into the Regen section of the gauge and would appear to have the same effect. I am guessing that pressing the brake pedal uses the motor to slow the car rather than brake pads, at least for light/moderate braking - is that right?

Do the brake lights come on when B/D1/D2/D3 are being used to slow the car?

 

[Verkehr]

A couple of related questions....

Is there any difference, in terms of Regen, between 'normal' braking and the D1/D2/D3 modes? Both move the needle into the Regen section of the gauge and would appear to have the same effect. I am guessing that pressing the brake pedal uses the motor to slow the car rather than brake pads, at least for light/moderate braking - is that right?

Do the brake lights come on when B/D1/D2/D3 are being used to slow the car?

Yes & brake lights only in B mode. D1-3 are no brake lights (D3 is my favorite because of this).

 

[forbin404]

A couple of related questions....

Is there any difference, in terms of Regen, between 'normal' braking and the D1/D2/D3 modes? Both move the needle into the Regen section of the gauge and would appear to have the same effect. I am guessing that pressing the brake pedal uses the motor to slow the car rather than brake pads, at least for light/moderate braking - is that right?

Do the brake lights come on when B/D1/D2/D3 are being used to slow the car?

They come on in 'B' mode, not sure about D1-3

Theoretically, there is no difference between modes in regards to braking. Pushing the Brake does start the regen mode even in 'D'. However in D1-B you get a preset amount of 'regen' instead of always trying to control it with your foot.

And of course Regen is only really invoked if your car has less than 90% battery. Otherwise the needle doesn't even pass the first Green Area.

 

[fyfchu]

I was happy to stumble on to this thread. When we first got our 2015 e-golf 6 months ago (hand me down from our son), we always used B-mode. As a former Leaf drivers, we enjoyed the aggressive regenerative braking. However, when I read the 100 miler thread, I noticed most of the successful people used D-mode, so we switched over. We understand the arguments for D-mode - you always want to preserve kinetic energy. However, this depends on how you drive, and it is pretty easy to determine for yourself what is the best mode. We mostly drive around town on city streets, and we aggressively hyper-mile. Using the egolf's car data report before we recharge we get the following:

B-mode - 5.2 mi/kWh - standard deviation - 0.23, n=13
D-mode - 4.8 mi/kWh - standard deviation - 0.26, n=22

It probably would have been better to randomize the weather variable by alternating modes after each time we charged. In our case most of the D-mode data are from winter (California) colder, wetter days.

 

[schleppy]

I find this incredibly gimmicky. All I want is max regen at all times. I would like to set that in software once (like Tesla), and have the car remember it. I have no need for the other drive modes.

I also would like to be able to turn "creep" off entirely. The e-Golf does a pretty nice job with this, but I would prefer to have it off at all times.

 

[JoulesThief]

The 4 different braking modes work perfectly for me. I drive in D mode most all of the time, and sometimes put it in D1 before applying the foot brakes. i see 5.7 to 6.3 miles per kwh almost all the time. YMMV, I am good at getting the most amount of miles per energy unit out of any vehicle I drive. A skilled/frugal driver with any basic knowledge in physics will get the most miles per kwh out of D mode and conserving momentum. Too much loss putting motion into electrical energy back in to the battery, 9 to 12% or more. "B" mode is hard on front tire wear, as are jack rabbit starts.

 

[JoulesThief]

A couple of related questions....

Is there any difference, in terms of Regen, between 'normal' braking and the D1/D2/D3 modes? Both move the needle into the Regen section of the gauge and would appear to have the same effect. I am guessing that pressing the brake pedal uses the motor to slow the car rather than brake pads, at least for light/moderate braking - is that right?

Do the brake lights come on when B/D1/D2/D3 are being used to slow the car?

Yes & brake lights only in B mode. D1-3 are no brake lights (D3 is my favorite because of this).

See "Regenerative Braking Settings" Says there that D2, D3 and B modes engage the braking lights.

http://insideevs.com/volkswagen-releases-details-2015-e-golf/

 

[Spektre]

The 4 different braking modes work perfectly for me. I drive in D mode most all of the time, and sometimes put it in D1 before applying the foot brakes. i see 5.7 to 6.3 miles per kwh almost all the time. YMMV, I am good at getting the most amount of miles per energy unit out of any vehicle I drive. A skilled/frugal driver with any basic knowledge in physics will get the most miles per kwh out of D mode and conserving momentum. Too much loss putting motion into electrical energy back in to the battery, 9 to 12% or more. "B" mode is hard on front tire wear, as are jack rabbit starts.

Please elaborate on how B mode is hard on front tire wear. I must've missed this...

 

[JoulesThief]

The 4 different braking modes work perfectly for me. I drive in D mode most all of the time, and sometimes put it in D1 before applying the foot brakes. i see 5.7 to 6.3 miles per kwh almost all the time. YMMV, I am good at getting the most amount of miles per energy unit out of any vehicle I drive. A skilled/frugal driver with any basic knowledge in physics will get the most miles per kwh out of D mode and conserving momentum. Too much loss putting motion into electrical energy back in to the battery, 9 to 12% or more. "B" mode is hard on front tire wear, as are jack rabbit starts.

Please elaborate on how B mode is hard on front tire wear. I must've missed this...

Take a physics course, then think about braking with all 4 tires versus only 2. Add in resilient eco tires with soft rubber compound that is optimized for conservation of energy, 'rebounding' and braking hard on soft rubber. If it's still lost on you, I can't help you.... ask for an explanation from the tire manufacturers. Acceleration and deceleration rates all have an effect on tire longevity. Perhaps you haven't owned any one car or bought multiple sets of tires for it to discover this on your own yet.

 

[forbin404]

The 4 different braking modes work perfectly for me. I drive in D mode most all of the time, and sometimes put it in D1 before applying the foot brakes. i see 5.7 to 6.3 miles per kwh almost all the time. YMMV, I am good at getting the most amount of miles per energy unit out of any vehicle I drive. A skilled/frugal driver with any basic knowledge in physics will get the most miles per kwh out of D mode and conserving momentum. Too much loss putting motion into electrical energy back in to the battery, 9 to 12% or more. "B" mode is hard on front tire wear, as are jack rabbit starts.

Please elaborate on how B mode is hard on front tire wear. I must've missed this...

Without the snarky answer that JT usually answers with,
Less Braking = Less Wear on Brakes
More 'Regen' = More Wear on Tires. (Because slowing down and accelerating rubs the tires off more)

But 'Hard on front tire wear'? I believe it's overstated, It's probably 10% more wear on tires and 50% less wear on the brakes. As tires are much easier to change than brakes I like those odds.

So my answer is , it wears the tires a little more.

 

[NeilBlanchard]

Max regen braking is always available - just use the brake pedal. Or put it in B.