One thing I don't like about B mode is that the brake lights come on if you completely remove your foot from the accelerator pedal.

 

Is that right? I've always wondered. My Kona Electric had g-force activated lights and they didn't always give people behind me enough time to react properly. I nearly got rear-ended a few times and I always suspected it was slow brake light illumination. So the ID.4 simply pops the brake lights on when lifting off the accelerator pedal? What triggers them to turn off? Applying power to speed up again?

 

It will still regen when rolling free...but it will be dependent on speed....topography and on board energy users at the moment....anywhere between 0.8-2.7 kW that will not be noticeable on display or driving feel.
Leveled surface will have very little regen when free rolling.
Free rolling is way more efficient than using B mode and forcing regen.

 

It will still regen when rolling free...but it will be dependent on speed....topography and on board energy users at the moment....anywhere between 0.8-2.7 kW that will not be noticeable on display or driving feel.
Leveled surface will have very little regen when free rolling.
Free rolling is way more efficient than using B mode and forcing regen.

Thanks for your many knowledgeable insights on this forum - i hope you will humour me with another:

Do you have simplified technical explanation for why D-mode is more efficient than B-mode (to me, it is a bit counter-intuitive)?

 

On my outbound trip I drove in B-mode and achieved 3.5 miles per kWh consumption. B is what I normally drive in since this is my second EV and brake regen has been part of my accepted conversion process. My average speed was around 45 mph.

On my return trip through the identical route I drove in D-mode and achieved 3.6 miles per kWh! I really did not expect that. I drove the same way in both directions moving with traffic road speed and slogging through stop and go traffic both ways. My return trip average speed was just slightly slower (it was getting dark) at 44 mph.

Your results are not unexpected. I've seen owner reports where D is more efficient and others where B is more efficient so it's not clear either mode is always more efficient.

The argument against B-mode is the car uses more energy to accelerate than the energy generated from regenerative braking so free rolling can be more efficient.

 

D is definitely more efficient on the freeway or free-moving situations, and also less driver fatiguing because it doesn't rely on precise foot/pedal control.

But I'm a B mode fan in stop-and-go, street, and any time when lots of speed adjustment are required. Not only do I believe the ID.4 operates as efficiently if not moreso, I also find it a more pleasant driving experience (i.e. more efficient for ME) because I'm not shuffling back and forth to the brake pedal.

 

D is definitely more efficient on the freeway or free-moving situations, and also less driver fatiguing because it doesn't rely on precise foot/pedal control.

But I'm a B mode fan in stop-and-go, street, and any time when lots of speed adjustment are required. Not only do I believe the ID.4 operates as efficiently if not more so, I also find it a more pleasant driving experience (i.e. more efficient for ME) because I'm not shuffling back and forth to the brake pedal.

I agree - In the Op's test, I would have been using D mode for the high speed section and B mode everywhere else. Over the past 9 years in my Mitsubishi, I've driven in B mode 100% of the time, but then it's an around town car and almost never goes on the freeway. Decelerating in B does not activate the brake lights in that car. I believe there is a Federally mandated rate of slowing which requires brake lights and most EV's are set up to only activate them when that threshold is passed. For 50 years I've been decelerating in 4, 5 and 6 speed manual transmission cars by downshifting and only showing brake lights when someone gets too close and I want to make sure THEY have a foot on the brake

Don

 

Yep, I drive ~100 miles roundtrip daily (~90% highway) and I can safely say that D-mode is consistently more efficient than B-mode for me. The difference is not typically huge, but I can usually do about 0.2-0.3 mi/kwh better on D-mode which adds up over the lengthy commute. Manually piloting D-mode is also more efficient than using Travel Assist for me, probably because I am able to ebb and flow with the pace of traffic better than the ACC which is constantly trying to maintain a set number. Even driving around town on the weekends, careful use of D-mode has proven to be noticeably more efficient even though I prefer B-mode for the quicker stopping capability in town.

 

The difference is not typically huge, but I can usually do about 0.2-0.3 mi/kwh better on D-mode

Depending on the circumstances that sounds like 5-10% better range. So maybe not "huge" but pretty significant.

 

I get better electron mileage free-wheeling in D, shifting to B to almost stop without brake pedal if necessary.

 

On my outbound trip I drove in B-mode and achieved 3.5 miles per kWh consumption.

<snip>

On my return trip through the identical route I drove in D-mode and achieved 3.6 miles per kWh!

I'm a big D fan and I don't doubt that you got better efficiency with D, but just let me point out that any kind of wind will affect your numbers in that kind of a test. I have a 70 mile commute towards the East when I have to go into the office. Based on my average efficiency for my trip into work vs. return trip home, I can tell you which way the wind was blowing that day, or at least the E/W component of the wind field vector. I might see something like 3.5 mi/kWh heading Eastward and 3.2 mi/kWh returning home, and sure enough when I check the wind it was coming out of the West that day.

 

Yes, the wind impact cannot be ruled out. You should do the same trip in a similar day with modes switched over to see if wind is a factor. But in general I think B should be more efficient in town and D on the highway.

 

I like the reassuring braking of ‘B’ mode around town but the free wheeling of ‘D’ on the highway. The right tool for the job. 😉

 

Maybe you don't have many hills on the freeway where you live but the big long descents charge my battery for several minutes at a time for a quarter of my highway trips. Using the friction brakes to avoid tickets on the descents seems like a waste to me. The head bobbing some have described disappears with familiarity and I feel using one pedal for both acceleration and deceleration is like a reinvention of the automatic transmission.
I admit to a learning curve to achieve smooth driving but it became second nature very quickly and driving without it leaves me wondering if my brakes are fading and sometimes well past the stop line at intersections.
It's a personal thing and I understand what works for me isn't necessarily what works for you.

 

Unless you're really good at holding the pedal at the coasting point (where there's 0 regen and 0 acceleration) in B mode, D mode is almost certainly going to be more efficient than B mode across the board, since D is near-coasting beyond the creep speed; pretty much the most efficient thing you can do in an EV is coast and let momentum carry the vehicle forward. B mode might be easier in stop-and-go traffic once you get used to it, but IMO the main reason why "one-pedal driving" got the efficiency reputation it has is because Teslas don't do blended braking.

 

There are of course a lot of variables across the board and some of them depend on driving style.

If you are going to drive in B mode I think you'll find is if you're driving in B around town you will improve the efficiency by using travel assist. This is because it will be able to regulate that perfect balance of the 0 regen and 0 acceleration better than most people can with their foot. It will also leave more room between you and the cars ahead, generally speaking, to recapture that energy more than coming up faster on the person and breaking late. That style can be more beneficial in D mode as you are trying to coast as long as possible. Both are a balancing act but the travel assist/cruise control, I think at least, is better at walking that tightrope most of the time.

 

Both D & B modes are very efficient and the choice between them shouldn't be driven (see what I did there?) by which is more efficient because the difference doesn't matter compared to the pleasure of driving in the one you prefer. But that said, D is almost always going to be more efficient due to the losses of getting energy out of and then back into the battery. A little thought experiment to illustrate:

1. Say you drive for 1/2 mile in D mode entering that stretch of road at 60 mph, take you foot off the accelerator just as you enter that 1/2 mile stretch, and then after 1/2 mile of coasting you are at 30 mph without having touched the brake pedal. So the stored battery energy due to driving is D mode (ignoring the air condition and keeping the lights on) is unchanged since you were coasting.

2. Now repeat that 1/2 mile stretch going in the same direction as before with the same wind & everything else while driving in B mode, enter at 60 mph, keep your foot on the accelerator a little longer, then remove your foot from the pedal timing it perfectly so that the regenerative braking has you exiting that 1/2 mile stretch of road at the same 30 mph as in the first scenario.

You will have more energy remaining in your battery after scenario #1, which is the same thing as saying that #1 is more efficient. The reason is because there are losses in converting battery energy in into propulsive force. I don't know the numbers exactly, but it might be something like 85% efficient--but whatever the exact number is it is certain that it is not 100%. And in turn there are losses in converting kinetic energy back into stored battery energy. Again, a reasonable guess might be 75% efficient but it is certain that it is not 100%. Both of those efficiencies would have to be 100% for B mode to be as efficient at D mode in this thought experiment.

Obviously there are a lot more factors that go into the final determination of whether you drive more efficiently in D or B mode, so I'm not saying that B mode is never going to be the winner for efficiency. But what is true in the competition between D & B is that B mode is working with the handicap of those round-trip energy conversion losses when converting energy back and forth between stored battery energy and kinetic energy.

But all of that pales in comparison to picking the one that works better for you. The differences based on efficiency are small in comparison.

 

D is fine on unobstructed free flowing interstates. Around town , on crowded two lane highways, and crowded interstates others choose when you will slow thus preventing planned gliding stops or slow downs. I just select accordingly.

 

I neat feature I'd love:

The car starts in B mode.

When I reach a certain threshold speed — maybe 55 MPH — and I'm driving a relatively steady speed, chime at me, and auto-switch me to D more, with a prompt to cancel.

When it detects speed variations,ie in traffic, chime me again and auto-switch to B.

User selectable feature, of course, because I know half of you would hate this idea.

 

I find the Travel Assist mode to be less efficient around town than doing it myself, largely because I can control how smoothly I brake and accelerate. In Travel Assist if I have cruise set at 40 mph and I'm following a car doing only 30 and he turns off, the car 'sees' that open hole in front of me and accelerates much more rapidly to get up to my 40 mph set speed than I would do - I would much more gradually accelerate. I wish I could control what Travel Assist does in such circumstances - It brakes much more severely than I would do myself and it accelerates much more aggressively too. I know I can get the job done myself more efficiently than that

Don

 

I have more of a problem with travel assist braking with the cars turning off than accelerating. The computer is way to slow to recognize that it has moved to another lane to turn. In those instances I know what's about to happen and I gently press the accelerator which I believe deactivates travel assist and then I resume. There is also a workaround to accelerating too fast. However, it does put a bit of cognitive load on you. I handle this by putting the speed of cruise at about the speed of the flow of traffic. If a hole opens up then it would be up to me to notice and adjust the cruise speed accordingly in either the 1 mph or 5 mph increments. I've really appreciated that you can do either.

 

Great info here. I’d also like to know how much regen B mode captures in AWD. VW hasn’t released any info on that.

RWD B mode provides 0.13g of regen, and a total of 0.25g of regen with brake.

How much does B mode in AWD regen? 0.13g? 0.18?? (Reviewers like Alex on Autos said he felt like the AWD provides more regen). And is the regen in AWD only at rear axle? Or both axles?

 

And is the regen in AWD only at rear axle? Or both axles?

ID.4 AWD is similar

 

Related required reading: What Exactly IS My Brake Light Doing Back There?

 

I made an interesting comparison this week regarding driving in D-mode versus B-mode. I have an 81 mile commute I do weekly. My starting elevation is 203 feet and my final destination is at 210 feet. In between is 10 miles of stop and go traffic through stoplights, commercial districts, etc. followed by 20 miles of secondary roads through rolling hills and two-lane highway, followed by 50 miles of two and four lane limited access highway with constant road speeds around 55-65 mph. There are two elevation hill climbs en-route, one being 980 feet, the other around 600 feet total, each with accompanying downhill sections.

On my outbound trip I drove in B-mode and achieved 3.5 miles per kWh consumption. B is what I normally drive in since this is my second EV and brake regen has been part of my accepted conversion process. My average speed was around 45 mph.

On my return trip through the identical route I drove in D-mode and achieved 3.6 miles per kWh! I really did not expect that. I drove the same way in both directions moving with traffic road speed and slogging through stop and go traffic both ways. My return trip average speed was just slightly slower (it was getting dark) at 44 mph.

From the simple perspective of driving the car I have to admit D-mode was more pleasant. The ID.4 really rolls effortlessly. It feels like it will coast for miles and it's smoooooth in D! No head rocking back and forth like in B-mode. VW seems to be pretty accurate when they say that D-mode will accomplish the same efficiency.

I know this is not a tightly controlled test environment, but it is a real world situation. As a result I'm much more interested in using D-mode than before. I'm doing an 800 mile trip this week and plan to try D-mode the whole way.

It doesn't matter. The difference comes from the driver. Using the brakes moderately activates the same regen in D mode as you get by lifting the accelerator in B mode. If you use too much regen on B mode by lifting off unnecessarily then you have to regain your speed. In short, driving smoothly in B mode can be more difficult for some drivers. I personally prefer it and have prefected my use. It's no more or less efficient, just more convenient.

 

It doesn't matter. The difference comes from the driver.

I think you may find considerable difference of opinion on this. Even VW says D is more efficient in the long run. Many others on this forum also have agreed that D beats B consistently.

 

From the simple perspective of driving the car I have to admit D-mode was more pleasant. The ID.4 really rolls effortlessly. It feels like it will coast for miles and it's smoooooth in D! No head rocking back and forth like in B-mode. VW seems to be pretty accurate when they say that D-mode will accomplish the same efficiency.

I know this is not a tightly controlled test environment, but it is a real world situation. As a result I'm much more interested in using D-mode than before. I'm doing an 800 mile trip this week and plan to try D-mode the whole way.

That's Newton's 1st Law applied to the nth degree!

 

Here's the regen in the eQ4 e-tron

 

What I find intriguing is the Skoda Enyaq 80 w/ regen paddles.

In B it behaves like the ID.4. They call that "max regen" after liftoff.

In Eco + D modes it uses "smart regen" that uses speed limits, radar, and even battery level to determine an "appropriate" level of regen.

Lastly, the paddles are used in conjunction with D mode to select 0 (no regen, similar to ID.4) then levels 1, 2 and 3 to steadily increase regen while coasting.

It doesn't sound as if the paddles can be used to increase the level of B mode regen, so yaz gots what'chaz gots.

 

Lastly, the paddles are used in conjunction with D mode to select 0 (no regen, similar to ID.4) then levels 1, 2 and 3 to steadily increase regen while coasting.

This sounds like exactly how my 2018 e-Golf works, except there are no paddles. You just press the floor shifter sideways to toggle between the 3 regen levels: D1, D2, and D3. B mode is something separate that you toggle on/off by pulling the gear shifter back. D3 is very close to B, but not quite as strong.

The 3 levels are actually very handy for setting regen for coasting down longer downhill stretches of varying steepness without having to touch any pedals at all (pedal-less driving! even better than one-pedal driving!).

 

Does the NA ID.4 have predictive braking? Like it would slow down before a curve or a roundabout?

 

Yes, that's referred to as Operator responsibility action.

[nothing AI automatic]

 

Currently no.

 

Is there more brake wear when using D mode and would that negate any perceived advantage in mi/kWh?

 

No, since the only time in D mode when the brakes are applied is during very hard braking, and under that situation the brakes also are applied in B mode. The first half of the brake pedal is all regen, up to 2x as much regen as B mode.

 

Hit “B” for a minute now and then when going down hills. Perfect!

 

From very early on, I found that B mode all the time works better for me especially on surface streets. I like the braking pedal feel better in B mode, Brakes feel even more artificial in D mode. I am always in Eco and my record for surface streets in B Mode is 4.5mi/kWh and 4.2 on my usual commute home (38 miles) if I'm really concentrating and behaving. It's not unusual to get in the mid 3's mi /kWh on speed limit runs.

I need to try some new D mode commutes to see what the difference would be. Vegas and back I was in B mode to take advantage of the long downhill regen opportunities. I noticed that AC Off vs ON makes no noticeable difference. I learned from my Prius, it's how one feathers the gas pedal makes all the difference. I haven't tried any other drive modes yet. 3.2 mi/kWh is what I can count on full range 5-100% 240 miles in B mode