D- or B-mode driving

General Discussion
1

What are your thoughts about using the regenerative B driving mode?
Personally, I never use it because I’m used to coasting a lot, and as far as I understand the regular brake pedal also regenerates power anyway when you use it.

So my thinking is, yes, B-mode might generate slightly more power perhaps, but you need to keep the gaspedal down for a longer time approaching an intersection anyway (instead of coasting and “save” power), using up more power before it starts to regenerate.

Could B-mode still be more effective and perhaps I should start using it (and ultimately gain some mileage)?

Another downside idea I have about B-mode are the brake pads.
Some years ago I had a C4 diesel with “automated manual gears”, which wasn’t a proper automatic but a manual gearbox that you didn’t have to select gears yourself.
This meant that it didn’t have any coasting when you let off the gas pedal. It behaved like a manual car and started to engine brake immediately.
This caused the brake pads to rust and get worn unevenly, because they were used so little, and I nearly failed the DMV test because of this.

Could the B-mode have a similar effect and lead to the decline of the brake pads?

Lets discuss. :slightly_smiling_face:

2

I might be wrong Jay but my understanding is that the regen braking does not come from direct contact between brake pads and brake disc, it’s more from gears downshifting as the car slows down, I think the word regen “breaking” is a little misleading.

Even when we manually use the actual brake pedal the auto box will downshift the gears which then starts the regen process (“breaking”).
Like I say I might be totally wrong :rofl:

As for your question, I always switch on “B” as I get into the car, but thats only because my son told me to because he has the PHEV Astra which is almost a DS4 PHEV in different clothes.

Oddly enough, we had a long discussion last night about how to save battery and in particular how and when to use E Save, apparently I’m doing it all wrong :crazy_face:

We both live in the same built up area, lots of stop/start driving, so he uses full electric with “B” mode on for this type of driving, he don’t use E Save until he’s on a longer journey so that the car will charge up the battery ready for when he hits a built up area.
He very rarely uses Hybrid mode in the built up area, in his opinion this is how he gets the best out of the PHEV system.

I have never used just full electric, I tend to go straight for Hybrid with “B” mode and switch E save on/off throughout my journey thinking I’m saving electric ?
This is what he thinks I’m doing wrong, he said I should leave the car “do it’s thing” , and use E save on a longer journey so that the car is charging the battery for “Free”.

I have to be honest, after discussing this last night he does seem to be getting better mileage than I am, plus he seems to be home charging his car less than I am, and we are talking about almost the same engine and battery in both cars !

It’s a difficult subject to get a good understanding .

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3

This link suggests that brake pad actually wear less on PHEV and EV vehicles ??

4

This is off the DS website regarding PHEV & EV maintenance.
See the paragraph “Is caring for my electric vehicle more expensive” ?

Screenshot 2024-12-13 at 09.26.16
Screenshot 2024-12-13 at 09.26.161441×599 72.9 KB

5

You’re most likely correct, and that is the same as my understanding of it.
Hence the brake pad wear issue question.
Regen braking is probably more like engine braking than brake pad braking, but it’s still braking (as in forced retardation).
Yes, the brake pads will most likely wear less with regen braking (probably goes for both D and B mode) and that’s the issue. The brake pads are used so little that they wear uneven and might start to get a little rust, making their brake ability worse. That’s exactly my point (referring to my paragraph about my old C4). :slightly_smiling_face:

I’m totally with your son regarding using electric only in built up areas (slow driving) and for using the engine in higher speeds (unless you will make it to the end on electric only), but I’m not sure I agree on the e-save. Using e-save is definitely not “free”. You can clearly see the petrol usage go up while using it, and general physic laws dictates that you can never transfer power with 0% loss.

For arguments sake, I’d be interested to hear what your son says about using D mode instead of B, pointing out that the battery regens power also with the manual brakes?
The difference there (if any) is what I’m interested in.

6

From what we’ve talked about he’s pretty convinced based on the sort of driving we do in our area, having the car in “B” mode alongside all other modes is a no brainer .

He’s had his PHEV 2 years and is pretty switched on with understanding how these sort of things work, I’m old school so it’s harder for me to get my head around :upside_down_face:

He did say, like you that using E save definitely raises the revs on the engine, so its not as clearcut as it sounds.
You think your saving your electric for later but in doing so you’ve used more petrol :thinking:

Looking back over the last two months since I’ve had the car I’m starting to think this is probably why I’ve not been impressed with the fuel consumption , I’ve been switching back and fore using E save in built up areas .

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7

I understand that you think that.
And perhaps that’s correct.
But I’m really interested in hearing any argument for B mode in comparison to lift & coast in D mode. In theory, I would argue that it’s definitely not clear cut in any way. I’m even leaning slightly towards that lift & coast in D mode might be the more efficient way to do it, if done correctly.
But I’m susceptible to arguments on both ways. :slightly_smiling_face:

8

Interesting about coasting.

He did say that he always uses “B” alongside any other driving mode, but he did also say that he has “mastered” how to get the most out of regen breaking by ever so slightly touching the accelerator as he’s “rolling” (coasting) either downhill or coming up to a junction/traffic lights.

He said he can see more regen breaking on the gauge by rolling to a stop but also at the same time just touching the accelerator.
He said it took him a while to get it right but he believes it gives him the best from both fuel & electric ?
If I’m honest I’m not fully sure what his actual technique is but as I said earlier he has had the car almost 2 years from new and he’s played around with how to get the most out of it.

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9

Sounds to me like he’s trying to achieve with B mode what D mode already does (if you lift & coast). :smile:
If you’d like to ask him, I’d love to hear his reasoning and theory behind this technique.

In rally, I believe it’s called “left foot braking” when you use the left foot to brake at the same time as the right foot is still on the gas.
He’s doing the same thing but the opposite, he’s trying to give gas at the same time as the car is braking. At least that’s what it sounds like.
At the end I’m not sure if we gain that much really, but for me it has almost become a sport trying to get the best mileage and the most economical driving as possible. :grin:
I should probably bother a little less, but I can’t help it. :innocent:

10

My driving style is an exact copy of @Jactac :slight_smile:
Regen braking comes from the fact that the electric motor that powers our cars is used as a generator instead when choosing “B”.
Instead of costing when releasing the throttle you use the last 5-10% to actually tell the car how much the generator (motor) should engage.
Properly used it gives a really fluid and controlled driving experience.
But as Jay pointed out - the brakes must be used every day to prevent them from sticking or rust.

11

And the actual question - Have tried both mdoes - cant see any real change in effiency between them.
With a properly modulated gas foot you can “coast” with B mode also, something I use when i want to pick up speed in a long downhill before an uphill (as an example).

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12

What I will say is, this is my first PHEV, and it definitely does make me want to try and drive more efficient.
It’s like a bit of a challenge.

The issue is finding the “sweet spot”, the exact driving mode/style that suits and gives the best performance, whether that be economy or enjoyment or indeed both.

At the moment it’s all still a learning curve for me, I don’t just jump in the car and drive, I’m forever fiddling around with something or switching from one mode to another, or E save on, E save off :crazy_face:

My son seems to have found his sweet spot with his Astra, whether I’ll find the exact same with my DS only time will tell, but at the moment I cant honestly say that the car is my most enjoyable that I’ve owned or to driven, it’s still feels like a bit of a challenge to get it right each and every time.

I’m not finding it a relaxed drive at the moment, I’m forever looking at the battery regen braking gauge, the fuel gauge, is the engine running, why isnt it running, should it be running, are the lights on, why havent they dipped from main beam, blah, blah, blah :woozy_face:

For example, my wife has a bog standard Renault Captur, it our daily run around, I just get in turn the key and go, I dont have to think about saving fuel, swapping to different modes, are the revs a bit high ect ect , its just key in, start up and go.

It’s just old school driving I suppose.

I don’t know if that makes sense ?

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13

Yep, but it does that also with manual braking. That’s why I don’t think that B-mode is a “super mode”. It’s just an easy (and perhaps lazy) way of getting the average Joe to drive a little bit more efficient.

That’s more or less my conclusion as well. But I still have the sense that, if done right, you can make it a little bit more efficient with lift & coast in D mode.
My theory is, better to lift the gas pedal earlier and “save” the power instead of lifting later and try to regen that same power. You always lose some energy when transferring it.
But I might be wrong.

14

Amen, brother! :joy:

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15

Took the car for a drive last night with E Save set to max for the full journey, without doubt the cars revs were higher and it used far more fuel than normal, I was actually very disappointed by how heavy it was on fuel. :unamused:

I set it in “B” to help with putting some charge back in and to hold E Save at Max, it did put some charge back into the battery, I think it went from 15 miles back up to 18 by the time I arrived at my destination, but in doing so I used more fuel than I normally would of, so I’m doubting E Save is all it’s cracked up to be.

It was very noticeable that the car was holding gears longer and producing higher revs between gear changes.

16

Yeah, the increased consumption is not minuscule.
Regarding e-save, I will do an experiment when I go away over Christmas.
I have a 500km drive and I’m thinking I will use e-save continuously, and only when approaching cities or stops I will let the battery roam temporarily. And then back on e-save max.
And when I have the same distance left that the battery says it can handle, I will end the journey on battery.
Just to see what happens.

17

Take extra in your wallet for fuel :rofl:

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18

The way PSA PHEV’s are set up is to use Electric as power first then switch to Petrol. For example, instead of using 2 gallon to travel 60 mile, you use battery for the first 30, then petrol for the next 30, so you have covered 60 mile on a gallon of petrol, 60 mpg sounds great. Hybrid varies but basically uses the same logic.

Basically the clues in the Title PHEV, Plug-in Hybrid Electric Vehicle, the PSA hybrid system is not the same as a Toyota/Ford system, the PSA version was not designed to charge while driving, that’s why we don’t have a ‘charge’ option, we just have an E-save or battery saver option.

To get best mileage, start with a full battery and use the Satnav, remembering that your battery will be empty at the end of your trip. Therefore, so say you’re visiting uncle Bob’s, you program uncle Bob’s as a way point and your home as a final destination. This way your car will ensure you use the electric charge for the whole trip and get home with an empty battery, you’ll probably have about 50% when arriving at Bobs.

E-Save recharges to battery to the required level, using petrol, charging puts extra load on the engine therefore, it needs more power to charge the battery, more power means more petrol - lower mpg. . There is no real benefit of E-save unless you must drive in a particular area in EV mode.

B mode, simulates engine braking, I only use in stop/start in traffic as it’s more relaxing or when driving downhill, other than that it’s coast and/or foot brake, which is assisted by regen, to get most of regen keep the indicator just off max, as anything above maximum is wasted.

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19

Thanks Stu,
good way of explaining :+1:

I think I’ve been using the system wrong.
It seems as though I would be better off leaving the car do its thing rather than me trying to juggle between modes, especially as I tend do more built up driving with a small amount of motorway driving to get to work each day, approximately 5 miles of motorway driving per day in total.

Would you suggest that I put the car into E save on the motorway part of my journey , or leave it in either electric or hybrid ?

When you say keep the indicator just off max do you mean the sliding re-charge indicator or dont set E Save to max ?

20

Satnav has never done that for me.
Even if I set a destination in the built-in satnav, the car will continue wasting battery on the motorway and will be drained long before I reach the next city.
In short, I’ve never seen any difference in behavior of the car when setting a destination or not.