2015 leaf D mode driving vs B mode

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bps88

Member
Joined
Jul 2, 2014
Messages
17
Hi Everyone,
i just leased a 2015 leaf sv and still waiting for delivery. I was curious, as it has the regular drive "D" and a "B" mode with greater regen power would it not be best to be driving in "B" mode all the time to get better regen and less charging/plugin ?

just a thought.
 
DNAinaGoodWay said:
More regen is better than breaking, when you want to slow down. D is better on the highway, when you want to coast without losing too much momentum.


yes, i understand this. does it mean that the battery will charge better while driving/get a longer range if driving in "B" mode with in city? i.e.: 14km vs 120 km ?
 
I drive 100% of the time in B-ECO. I use the regen instead of the brakes to do most of the stopping. I also coast as much as possible by modulating the accelerator pedal to zero power. This is the most efficient way to drive. I use ECO mainly because it makes the stroke of the accelerator pedal longer so that it is easier to modulate. The net result is that it is almost like one-pedal driving, which I find very convenient.

Best wishes on your new LEAF.
 
Unlike ECO mode, D/B only changes the amount of regen with no pedals pressed.

I generally use a mix of them. Checking the GOM, the range does not change when switching, while ECO does show a difference.

Basically, it depends more on how you drive than using D/B. I use B to slow down to minimize using brakes (0% efficient). You can also use D to slow down, but it takes longer. In either mode, pressing the brake pedal will increase regen. However, I do not know how much real brake is applied under any scenarios other than stopped.
 
I am blessed with a 5.2 mile commute, one way. I don't like ECO mode, a bit too sluggish for me and D is more fun to drive, plus the actual savings (to me) isn't probably worth it.

I am in D mode most of the time, while approaching red lights , I use B mode ...my pseudo paddle shifter :)

Even thought I have QC, have been able to just use trickle charge overnight so I am happy with D mode.

Cheers
 
NasGoreList said:
I just wish leaf had stronger regen mode overall, meaning max regen as soon as you lift completely of the accelerator pedal

This. And don't even bother trying to blend the the friction and regen brakes, since no-one can ever seem to get that perfect. Just have all regen on the gas pedal and all friction braking on the brake pedal. Then you always know what's happening and it's a simpler design.
 
pkulak said:
Then you always know what's happening and it's a simpler design.
Indeed. The way it's presently set up, they're trying to emulate ICE behavior, and emulation is never going to operate as well as native mode. Dammit, we know we're driving electric vehicles! At least give us a configuration option to make them operate more in accordance with their true nature :)
 
pkulak said:
NasGoreList said:
I just wish leaf had stronger regen mode overall, meaning max regen as soon as you lift completely of the accelerator pedal

This. And don't even bother trying to blend the the friction and regen brakes, since no-one can ever seem to get that perfect. Just have all regen on the gas pedal and all friction braking on the brake pedal. Then you always know what's happening and it's a simpler design.

That is what B mode should be.
D mode should be what B mode is.
The current D mode should be removed.
 
goixiz said:
In B mode which battery is it recharging ?
Regenerative braking charges the main traction battery. B mode just allows a higher rate of regen braking (and charging, of course).

The 12 V accessory battery gets charged by the main battery whenever the car is being driven (ready mode) or is charging. (But the control software isn't very good so the 12 V battery sometimes doesn't get charged as well as it should; there are many threads on the subject.)
 
bps88 said:
Hi Everyone,
i just leased a 2015 leaf sv and still waiting for delivery. I was curious, as it has the regular drive "D" and a "B" mode with greater regen power would it not be best to be driving in "B" mode all the time to get better regen and less charging/plugin ?

just a thought.


If you mean best as in most range then no. Regen brakes are nice when you have to use the brakes but for the best range you want to avoid the use of brakes, friction or electric. Even though all of the systems in the leaf are effecient there are still substantial losses. If you accelerate from 0 a % of the energy coming out of the battery makes the car go forward (kinetic energy), a % is lost to friction, wind, tires etc.. You have no control (after tire choice and psi are set) on these losses, they are what they are. The brakes are a device that convert kinetic energy, when you brake with regen a % of the kinetic energy goes back into the battery, friction brakes convert it to heat. If you used less energy initially (lower speed, coming off the accelerator a long time before the stop) and then coasted and came to a stop exactly where you wanted to then you have used energy from the battery at the highest possible % of efficency. You will take far less energy out of the battery than the net use if you maintaned the higher speed and then used regen.

You have to find the best ballance that works for you. The most effecient system is the one that I hear vw/porsche use, with what they call sailing. Lift off of the acceleartor and the car will coast. They are even talking about doing this with their ICE DCT cars.

If B mode was the most efficent they would use it as standard and let the results show up in the EPA tests. It's made for going down hills, not for efficency. You can maximize your efficency in it but if you modulate the pedal to coast and B mode brings on more regen than D would when you are trying to find that sweet spot it will not be as efficent.
 
+1 on ^

dgpcolorado said:
goixiz said:
In B mode which battery is it recharging ?
Regenerative braking charges the main traction battery. B mode just allows a higher rate of regen braking (and charging, of course).

The 12 V accessory battery gets charged by the main battery whenever the car is being driven (ready mode) or is charging. (But the control software isn't very good so the 12 V battery sometimes doesn't get charged as well as it should; there are many threads on the subject.)

Hopefully, they've improved this by now. My '15 SV has no solar panel to help out.

I find the '15 shows some regen even when I leave with 100%, not much, but noticeably more than the '12.
 
DNAinaGoodWay said:
+1 on ^

dgpcolorado said:
goixiz said:
In B mode which battery is it recharging ?
Regenerative braking charges the main traction battery. B mode just allows a higher rate of regen braking (and charging, of course).

The 12 V accessory battery gets charged by the main battery whenever the car is being driven (ready mode) or is charging. (But the control software isn't very good so the 12 V battery sometimes doesn't get charged as well as it should; there are many threads on the subject.)

Hopefully, they've improved this by now. My '15 SV has no solar panel to help out.

I find the '15 shows some regen even when I leave with 100%, not much, but noticeably more than the '12.

I only have experience in my '15. I start my drive out with a short in town then down the Niagara escarpment (same drop as Niagara falls). I've never had a time with no re gen available, around 98% when going down, but it is limited to about 25% of max.
 
DNAinaGoodWay said:
I agree that minispeed's summary of driving efficiently was well done!
minispeed said:
I only have experience in my '15. I start my drive out with a short in town then down the Niagara escarpment (same drop as Niagara falls). I've never had a time with no re gen available, around 98% when going down, but it is limited to about 25% of max.
That is a notable improvement. But since you live in snow country I predict that you will find that regen drops off when the battery gets cold in winter. At some low temperature regen will likely disappear entirely. I'll be interested to know how that shakes out with the 2015 model battery.
 
dgpcolorado said:
DNAinaGoodWay said:
I agree that minispeed's summary of driving efficiently was well done!
minispeed said:
I only have experience in my '15. I start my drive out with a short in town then down the Niagara escarpment (same drop as Niagara falls). I've never had a time with no re gen available, around 98% when going down, but it is limited to about 25% of max.
That is a notable improvement. But since you live in snow country I predict that you will find that regen drops off when the battery gets cold in winter. At some low temperature regen will likely disappear entirely. I'll be interested to know how that shakes out with the 2015 model battery.


It would be nice if the engineers were smart enough to allow the heater to run off regen when the battery is too cold. I'm not worried at all about losing it, I usually start off a little slower so that the drop keeps me at no more than 110. In my insight in the cold the drop would limit the car to about that in a neutral coast, in the summer the warm air would let it gravity pull it much faster.
 
minispeed said:
It would be nice if the engineers were smart enough to allow the heater to run off regen when the battery is too cold.
This may already be the case... wouldn't the regen allowed into the battery be the net of what the motor-as-generator is producing less any power needed for accessories?
 
One of the neglected modes and a very traditional one in old time EVs (pre-regen) is COASTING.
'
The leaf offers 3 levels of regen.. very mild in D
medium in Eco
and max in B.

There is some buzz about the Ioniq getting 130 miles from a 28KwH batt back.
I think the secret is they have enabled a coasting or free-wheeling mode.

In our cars.. choose N to coast.

On minor slopes, when any regen at all will slow you too much
you are forced to use some accelerator to maintain your speed..

Try N instead !

--To answer the question directly.

B mode will decelerate you unless you are extremely accurate with your throttle control
( this is America there are 6 guys who can drive a constant speed without cruise and 4 of them are too old to care anymore)
every time you decelerate... you have to expend energy to get back to speed.
In B mode.. unless you are in rolling hills.. steep rolling hills.. this is counter productive.

Energy Conservation... not squandering the energy you invested to get to speed... is a big part of
maximizing range and hence efficiency.

An automatic freewheel setting.. could in certain settings... be an asset.

The Ioniq has some sort of paddle shifter to toggle between regen braking levels.
a tad less involved than the D/Eco button, and shifter wiggle for B and Out of B.

Nissan may have intentionally made it more difficult to chose B.. precicesly because it is NOT the most efficient
way to drive the call routinely.

I was hoping to find some commentary of Coasting as a strategy.
 
blimpy said:
I was hoping to find some commentary of Coasting as a strategy.
Shorter slopes: enough throttle to to keep it just above regen (it really isn't that difficult.)
Longer slopes: cruise control
 
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