What's most efficient. Drive in D or drive in B?

[cove3]

I'm a little confused on the manual recommendation about driving efficiency, which is to anticipate and coast with as little braking as possible. You can't coast in B, but you get full regen

When in D, however, there's no regen so you can coast to slow down, but when you hit the brake, there is some regen because the dial goes over to the charge portion during braking. I assume there's some mix of regen and actual brake pad wear/heat taking place

Thus the question: what is the most efficient driving method
(1) D with no regen and the ability to coast to slow down but some need to brake which will generate some mix % of regen & pad wear heat
or
(2) B with no ability to coast but with full regen?

It seems like the answer is what percent of regen vs brake pad wear/heat happens when you brake. If most of braking goes to regen, then it seems D has all the advantages of B, but with the ability to coast to slow down

Ron

 

[GadgetGav]

I haven't read the manual's recommendations on driving efficiently, but it sounds like they don't fully explain the way the car's systems handle coast and regen anyway. My best guess is that most hybrids and EVs use regen first as the brake pedal is applied and then bring in the friction pads if needed. My experience with servo motors tells me that it could stop on a dime using just electric regen if it wanted to, but that's probably hard to program in a car and hard for a driver to get used to.
I think the eGolf does a mix of electric and friction braking in all cases where the brake pedal is pressed, and electric regen only if you're trying to do one-pedal driving in B or D3.
In my opinion, the eGolf does a much better job transitioning from regen to friction under braking than the Lexus CT200. My wife drives one of those and while it's a nice car, it takes me a long time to get used to the brake pedal enough that I can brake smoothly from any speed. I don't find the same problem switching to the eGolf from a Golf GTI. Maybe it's just that the VW pedal feel is different to Lexus.

 

[svhoneymoon]

I feel like B is a must for stop and go traffic, since you can sort of continuously feather the throttle and rarely ever need to hit the brakes.

It gives a very direct feel that makes it very pleasant to drive even given the circumstances.

The other day I did 4.8 mi/kWh on my 23 mile commute using B (avg speed 21 mph.. can't wait for HOV).

Doing that same trip in D would have been a chore.

 

[cove3]

The owners manual states there's no regen if the battery is fully charged and reduced regen if it's above 85%.

I've concluded if maximum range is crucial, one should drive in D, coast as much as possible, only using the brake regen for the last 10-20% if that. This makes sense by thinking the extreme case of never using the brake. If you never use the brake, it means you never had to accelerate more than necessary in the first place. Thus total energy is minimized, since regen can only recapture a fraction of the energy expended to accelerate, although more time will be required

It would be interesting to know how much additional range one could squeeze out this way. Is it enough to make it worthwhile? It seems like it would be highly dependent on the regen efficiency number.

Ron

 

[NeilBlanchard]

It is best to coast when you need to continue driving; which is the default mode in D. When you need to slow down, then regen is great.

The major difference is when you coast, you are using the kinetic energy of the moving car in the most efficient way possible - to move the car forward. You will tend to accelerate for a shorter time, and then coast, and then either accelerate some more, or use regen to slow down.

VW learned this when they designed the XL1, and I am very glad the e-Golf also has this feature.

 

[cove3]

I was told on the i3 forum that the i3 has no D capability. Regen is always on and in only 1 powerful setting that has to be controlled with the gas pedal. This seems to me to be to be a major disadvantage vs the e-golf which has D no regen coast plus 4 levels of regen

Ron

 

[eGolf2015]

I've inquired with VW twice in the past 6 weeks for advice/guidance on most efficiently and safely (for the car) using B and the various D modes. (Elsewhere on this forum someone mentioned that their dealer told them it was harmful to the car to drive in B too much.)

First time was via online chat on VW's website. Rep wasn't knowledgable on regen braking but promised that a technical specialist would follow up with me within a few days. Never heard from anyone.

A few weeks later a rep contacted me to follow up on the VW Quality Survey that I had completed. I brought up the regen question again and told her that nobody got back to me following my first inquiry. Again, I was promised further follow-up from a tech specialist, but never head from anyone.

Between the ongoing CarNet issues and VW's failure to provide adequate training on the eGolf at the dealership level and lack of responsiveness at the corporate level, my opinion of the company has changed significantly for the worse since we bought our car. It's a shame, because I really like most aspects of the car itself, and we've had great experiences with our 3 prior VW's.

I'll be looking to replace my ICE Jetta within the next 6-12 months, and it is looking less and less likely that it will be with another VW.

 

[NeilBlanchard]

You are correct - the i3 has a lot of regen on the accelerator pedal, when you lift your right foot, and in order to (sorta') coast, you have to find the "neutral" position on the accelerator pedal.

I agree that it is too bad that VW seems to have not trained people very well. Driving in B mode won't hurt anything, but it won't be the most efficient way to drive. As I posted earlier, coasting is the most efficient way to drive, and use the right amount of regen to slow down. The basics of efficient driving are the same for any car, no matter what the drivetrain is.

 

[cove3]

<<<I'll be looking to replace my ICE Jetta within the next 6-12 months, and it is looking less and less likely that it will be with another VW>>>

You might find things as bad or worse with other brands. Try calling Microsoft for help. Everywhere you look in our society, you see the same. Over extended, cutting corners, misrepresentation, etc. Forums, internet searches and other forms of self help can fill the gap. I've never failed to find an answer that way

For me, the car or whatever product function is the thing, and I'll put up with the rest. When it comes to bevs or phevs, no other car compares to the e-golf or upcoming audi e-tron

Ron

 

[gene]

<<<I'll be looking to replace my ICE Jetta within the next 6-12 months, and it is looking less and less likely that it will be with another VW>>>

"You might find things as bad or worse with other brands".

Here again, Tesla is extraordinary. Any tech question I have ever had was answered by the tech department by whomever answered the phone. Never did I hear "someone will get back to you". Yes, I know, it is more money, but if you can rationalize a Tesla purchase, I think you'll be pleased. 2 years and 45,000 miles, I could not be happier!

I do need a second EV, I have tried most of them and with each visit to a dealer, I cringe, and wonder if I should try to afford a second Tesla. I have had decent experience at a couple of Nissan dealers but VW, Chevy, Fiat, Ford experiences were terrible.

 

[cove3]

Tesla service is artificially temporary because it's financed by the euphoria of the stock price. Once its starts to go bankrupt due to competition, series 3 product delays and high price, and battery factory economics, the service will dry up. I'm not sure about the residual value of the car, as it might achieve collector status.

Ron

 

[preilly44]

Ron, where do you get this stuff? It's pretty comical.

 

[cove3]

I read a lot of analyst and technology reports and study what the competition is doing. The net is on going losses, overvaluation, questionable mega battery factory economics, high debt rated junk, and most important 20+ competitive vehicles in the works attacking the entire Tesla spectrum and smothering it.

1. 1.2B of cumulative losses. Assuming 50K S/roadsters sold, that's 24,000 loss/car
2. No profits per Musk until 2020 at earliest
3. 800M of debt rated junk by S&P, 6 levels below investment grade
4. Late on X and Model 3, probably 2018
5. Counting on volume Model 3 but many estimate it will cost 50K. Also, 5+ other 200 mile cars will be out around the same time, including GM, VW, BMW, Nisson, Electra-King etc
6. At least 7 companies working on S type luxury bevs, including BMW, Audi, MB, Porsche, Aoxin Ibis, Jaguar, Range Rover.
7. China market is not materializing + China is making it['s own including S competitor Aoxin Ibis
8. Mega battery factory cost reductions not achievable per numerous studies
9. A ton of PHEVS covering the entire low to high end spectrum are out or soon out, including new Volt, Audi 3 e-tron
10. Japan decision to go all out for fuel cell. Toyota, Honda, Hyundai, BMW, Audi A7 e-tron etc including carbon bodied
11. Stock is priced to achieve 35% ROEs and grow 30% for the next 40 years.
12. Burning through cash at an alarming rate
13. Limited in house carbon fiber and fuel cell skills when BMW, VW, others have or working on carbon body bevs, fuel cell cars
14. Untrustworthy announcements. Schedules, volumes, BMW partnership immediately denied by BMW, in 2013 that Model 3 would be shown at 2015 Detroit auto show, etc
15. Question accounting and risks: Disclosure, carbon credits, underestimated reserves for warranty, risk of residual values after leases expire, dependence on continued Federal/State incentives, battery life/capa ity risks esp with frequent DC charging

There's a bunch more but I'm running out of room. The window of stock market euphoria and having the market to themselves and still not making money is fast closing. Recall the ending of Butch Cassidy and the Sundance Kid. Newman and Redford going out six guns blazing, unaware there were 800 Mexican Federales on the rooftops with rifles. Whatever meager profits exists in bevs are being eyed by 10 majors with vastly greater resources and ICE profits to fall back on.

Ron

analysts at Bank of America/Merrill Lynch issued a negative note on the electric car maker this morning, and cut its price target on the stock to $65 from $70.

 

[NeilBlanchard]

I hope we can veer back on topic ... please?

I signed a lease today on a white e-Golf, and I will be posting consumption numbers - so you all can compare, and we can see that VW was right to design the e-Golf with coasting. The thing that will come with a little ecodriving practice is less acceleration, more coasting, and only enough regen to avoid hitting the brakes.

 

[cove3]

<<<less acceleration, more coasting, and only enough regen to avoid hitting the brakes>>

If you use any regen 1-4, you can't coast. It's seems to me the optimal is to drive in D, coast and use minimal brakes to regen. Of course, this all depends on what % of the energy expended to get momentum is regened. If it's 90% it won't make much difference, but if it's 40% it might. But if range or mpg isn't a concern, 1-4 is more fun and saves time

Ron

 

[Carc]

Forget using the regen - it's just a total buzzkill. The genius of the golf is that you can turn the damn thing off and coast super smoothly - which was impossible in our old leaf. Regen setting sreally don't affect range significantly - I have only found it useful as a kind of downshift on freeway off ramps or steep hills where it definitely comes in handy.

 

[NeilBlanchard]

Right, this is what I am looking forward to driving our e-Golf. Coasting most of the time, and only using some regen when I need to slow down.

I have been ecodriving for at least 7 years, and my daily driver - up until leasing the e-Golf - is a Scion xA. It is rated at 30MPG Combined, and I have been averaging 46MPG+ all year round. I have to put in the clutch, or neutral and the engine still idles. So, driving the e-Golf will be a pleasure.

We have a Leaf as well, and you can hold it in neutral for 2 seconds to coast (or put it in reverse above 7MPH), so it has about the opposite driving technique. Regen by default (two levels in the later generations, in D and B) and you have to think to coast. Okay, but not as easy as the e-Golf.

 

[cove3]

<< I have only found it useful as a kind of downshift on freeway off ramps or steep hills where it definitely comes in handy.>>>

Why wouldn't a major advantage be one pedal driving?

Ron

 

[NeilBlanchard]

My concern is what has the best efficiency. Since that meant that I owned manual shift cars, I cannot say I want to drive with one pedal. Driving an EV is easier than an automatic, and they are a different animal than an ICE, so I am fine with driving in the way that yields the best range.

 

[BeardedRobot]

I thought I’d weigh in with some real world numbers. I have a very consistent commute, which includes some surface streets, some highway, and one big hill in the middle. I’ve done the commute now a handful of times using the regen settings of B and D to record and compare the miles per kWh efficiency of each setting. I tried to make it as close to an apples-to-apples comparison as possible (same climate control settings, avg MPH, etc.).

In D mode:

4.4 M/kWh
24 mph avg

In B mode:

5.0 M/kWh
24 mph avg

For my commute, at least, there’s a clear (13.6%) efficiency advantage to driving in full B regen mode. If applied over a fully charged 24kWh battery (though I don’t think we ever get to use all 24 kWh), driving in B mode would add 14+ miles to my total range.

Switch to B, you’ll like it

-JM