Regenerative braking vrs normal braking??

[phevman]

Hi Guys

What is the main difference using regenerative breaking/paddles and just normal breaking?

My understanding is normal breaking will put charge back into the battery, what is the benefit selecting 'B' and using the paddles.

Also, would leaving the selector in 'B' use more energy when you need start accelerating again?

 

[jdsx]

Can't give you a definitive reply, but in my experience there isn't really much difference between the two. However, I like to paddle, and use B0 whenever I can - this is like 'coasting' and if you can get used to looking far ahead is good for saving energy.
I am told that even if you are in B5 you don't use any more energy on accelerating - the energy is coming from the battery at that point and so can't in any sense be going the other way at the same time!

 

[aitchjaybee]

when in drive (D) its the equivalent of B2. ie, when you lift off the accelerator, there is a little bit of regeneration happening through the electric motors back to the battery (same as current F1 cars have on rear axle). If you brake, it applies max regen (equivalent to B5) but if thats not enough, the brake pads apply to retard the car, and thats wasted energy (but helps you not plough into the car/person/wall in front].

the car is pretty sophisticated and paddling v leaving in D doesn't give a huge advantage. If you manually change the regen using the paddles, you can look ahead a little better than the car would do and choose to coast (B0), lightly retard the speed (B1) or use it like a brake (B4 or B5).

If you are in B mode (B0/B1/B2/B3/B4/B5), turning on cruise control automatically defaults back to B2 (the same as in D)

Two warnings: (1) B5 slows you as much as gentle braking but no brake lights illuminate so be careful if you have drivers behind you. (i know they should anticipate ahead too but I found too many drivers behind don't anticipate and so stopped using more than B2 if car behind me) And (2) with a full battery (eg having charged and set off) the regeneration is almost nil, so paddling up to B5 doesnt actually slow you down much as the battery can't over-fill, just so it doesnt catch you out. The first few miles of a journey using B0 is most effective.

i do the same daily A road 20 mile each way commute and on average using 'eco mode and D' gets me home with about 8 miles indicated remaining, 'eco and paddling' i get home with 10 miles indicated remaining, so it has a noticeable, albiet minor, difference.

There's a thread on paddling for fun, and thats the main reason i do it. Maybe I should I get out more, but hey, it makes me smile

 

[user 258]

when in drive (D) its the equivalent of B2. ie, when you lift off the accelerator, there is a little bit of regeneration happening through the electric motors back to the battery (same as current F1 cars have on rear axle). If you brake, it applies max regen (equivalent to B5) but if thats not enough, the brake pads apply to retard the car, and thats wasted energy (but helps you not plough into the car/person/wall in front].

SNIP

i do the same daily A road 20 mile each way commute and on average using 'eco mode and D' gets me home with about 8 miles indicated remaining, 'eco and paddling' i get home with 10 miles indicated remaining, so it has a noticeable, albiet minor, difference.

Hi,
I would pretty much agree with everything you have said. The only thing I can add is that while using the footbrake shouldn't engage friction brakes until more braking is required than can be provided by regen, I strongly suspect that in reality Mitubishi start to apply some (but probably not much) friction braking as soon as you depress the footbrake in addition to the regen braking. I think they have probably done this to make the transition from regen to friction braking smooth. Regen braking doesns't work well at speeds below about 6mph or when hard braking is needed. With a Prius you can just about tell when it swaps between regen and friction. This extra friction braking is obviously avoided by using paddles (or just B5) which probably accounts for the increased EV range left when you paddle.

Kind regards,
Mark

 

[phevmike]

I've had quite a bit of debate with my family about whether the re-gen affects acceleration, I know it doesn't, but they insist if the car is in B4/B5 it's pulling on the driving wheels more. Nonsense! I leave the car in B3 permanently, and the way I drive I'm hardly using the brakes at all, any steep hills and I'm gaining 2-3 miles in range and I seem to average around 24/25 miles of 'real' range when the car is reading 22/23. Indeed the only issue I have with the range is that only once has it read 32 miles after a full charge up. Charged it up this morning and it was again 29 miles (lowest after a full charge was 26!).

 

[maby]

...
Hi,
I would pretty much agree with everything you have said. The only thing I can add is that while using the footbrake shouldn't engage friction brakes until more braking is required than can be provided by regen, I strongly suspect that in reality Mitubishi start to apply some (but probably not much) friction braking as soon as you depress the footbrake in addition to the regen braking. I think they have probably done this to make the transition from regen to friction braking smooth. Regen braking doesns't work well at speeds below about 6mph or when hard braking is needed. With a Prius you can just about tell when it swaps between regen and friction. This extra friction braking is obviously avoided by using paddles (or just B5) which probably accounts for the increased EV range left when you paddle.

Kind regards,
Mark

I suspect that the reasoning is more a safety measure, you know. To have the brakes work the way you describe - as much regen as possible, only falling back to friction when it cannot cope on regen alone, really implies a "brake-by-wire" system which is a safety nightmare. My bet is that the brake pedal on the Outlander is pretty much the same as on any other car but with an electronic motion sensor to allow the computers to control the regenerative braking and a bit more free movement before the friction brake engages than would be normal. That way, even in the event of a complete failure of the computer system, it just degenerates to a standard setup.

 

[aitchjaybee]

very fair replies ref braking starting at same time as adding to regen level Avensys and maby, agree thats a fairer reflection. My description a little idealistic!

 

[PHEVclub]

phevmike surprised your only seeing 32 as a max. Switching between B0 & B5 and coasting as much as possible I am seeing between 35 & 39 after max charging. What figures are others seeing, and which B setting are they using?

 

[Rocket]

Question - Is B0 actually 'coasting' as is being referred to?

I ask as it is mentioned in the highway code not to do it, questionable whether it is actually illegal of not but if lets say you are involved in a very serious accident whilst 'coasting' in B0 and the accident investigators download the history of what your car was doing then could this cause legal issues?

Coasting. This term describes a vehicle travelling in neutral or with the clutch pressed down. It can reduce driver control because

engine braking is eliminated
vehicle speed downhill will increase quickly
increased use of the footbrake can reduce its effectiveness
steering response will be affected, particularly on bends and corners
it may be more difficult to select the appropriate gear when needed.

https://www.gov.uk/general-rules-all-drivers-riders-103-to-158/control-of-the-vehicle-117-to-126

Technology has advanced I'll grant you, but a prosecution lawyer would no doubt pick up on the fact that you were in B0 and coasting when the accident occurred.

Just chucking this out there, love a discussion!

 

[user 258]

Hi,

Coasting. This term describes a vehicle travelling in neutral or with the clutch pressed down.

Since the PHEV isn't in neutral and doesn't have the clutch depressed then it doesn't sound like highway code coasting to me. Although some of the reasons why coasting is bad as listed would also apply to B0.

I've probably said this before, and at the risk of being boring and repetitive, why not just drive in D mode and reserve the higher B modes for controlling speed when decending hills? The B modes, as described in this forum, are essentially just a gimmick that serve no significant purpose and if overused will only increase the chances of a collision which makes all the talk of the safety of winter tyres in another topic seem silly.

Kind regards,
Mark

 

[Hypermiler]

I use B0 a lot, it is my default mode. I paddle up for corners, downhills and junctions and use the brakes lightly, particularly making sure I use them when someone is behind me. I do this on the basis that it is better to glide under the cars own momentum than be constantly charging and discharging the battery (and so eventually impacting its optimal performance) and because there will be big efficiency losses in regen.

I know it doesn't make technical sense, but if I drive in anything above B0, I feel like there is drag when I am using my light foot on the throttle - I reckon I can always tell if I'm not in B0 (I could try it blindfolded!!). Perhaps with a heavier press on the throttle it makes no difference, but I think I can feel it.

The maximum ev range will depend so much on terrain. I live in a relatively flat area, but when I do get to regen down a hill or zoom down one and then coast part way up the next, it is great! Don't you just hate it when you have to stop, say to get round a parked car, when you are having a good glide...

On the legal point, I don't think B0 is the same as being in neutral in a normal car but clearly you have to use it with care as you can get a lot of speed up quickly on a downhill. But perhaps we ought to call it gliding rather than coasting! :idea:

H

 

[PolishPilot]

I am still learning, but I love the B6 in the city, you just do not have to touch the brakes almost at all, except for a full stop.

Creeping in traffic jams is a pleasure now.

 

[tarq]

I must admit to being a bit concerned about the 'B' modes with the PHEV.

I use 'B' in my Prius & find other cars do seem to get close, as they haven't realised I'm slowing, usually because they are travelling too close in the first place! :shock:

It certainly educates driving a hybrid.

Perhaps we should get a led banner in the back window that lights up 'Slowing', when in 'B' modes.

 

[Fragge]

From what I've been told the brake lights comes on under heavy regenerative braking.

 

[user 258]

From what I've been told the brake lights comes on under heavy regenerative braking.

I have tested a UK PHEV and at speeds upto 30mph the brake lights did not operate in B5 when the foot is removed from the accelerator pedal. I think it highly unlikeluy they would only operate at higher speeds.
Kind regards,
Mark

 

[Poins]

I wonder how big a job it would be to wire the car up so that the B paddle also triggered the brake lights. I gather that the BMW i3 automatically triggers the brake lights when you lift your foot off the accelerator.

 

[maby]

I wonder how big a job it would be to wire the car up so that the B paddle also triggered the brake lights. I gather that the BMW i3 automatically triggers the brake lights when you lift your foot off the accelerator.

I can't believe that it is that simplistic - you need a system that takes into account all parameters and only illuminates the brake lights when the car is decelerating significantly.

 

[Fragge]

Shouldn't be a problem, you only need an accelerometer to determine if the car is decelerating. That sensor is already present in the car...

 

[greendwarf]

I wonder how big a job it would be to wire the car up so that the B paddle also triggered the brake lights. I gather that the BMW i3 automatically triggers the brake lights when you lift your foot off the accelerator.

Well frankly that's just bloody annoying, especially at night in city traffic. I get pissed off by people using their foot brakes to hold cars when stopped rather than putting on the handbrake (as I was taught 40+ years ago!).

I don't see the problem, described above. I've always used engine braking to slow down with no brake lights and have never heard this was an issue for following traffic - surely the B modes are just the same. :?

 

[maby]

I wonder how big a job it would be to wire the car up so that the B paddle also triggered the brake lights. I gather that the BMW i3 automatically triggers the brake lights when you lift your foot off the accelerator.

Well frankly that's just bloody annoying, especially at night in city traffic. I get pissed off by people using their foot brakes to hold cars when stopped rather than putting on the handbrake (as I was taught 40+ years ago!).

I don't see the problem, described above. I've always used engine braking to slow down with no brake lights and have never heard this was an issue for following traffic - surely the B modes are just the same. :?

I think that the issue is that the Outlander regenerative braking on its maximum setting can decelerate the car far more than conventional engine braking - to a similar extent to what the footbrake can do.