Has regen been reduced

[cove3]

In the same way you could take an ICE car, take it out of gear and let it coast

What I meant was not constantly moving the shift lever back and forth, but by just letting up on the gas. One owner told me you do it by finding a certain position on the gas pedal, but if true, it seems you'd have to go through some regen to get to that position

Ron

 

[elptex]

In the same way you could take an ICE car, take it out of gear and let it coast

What I meant was not constantly moving the shift lever back and forth, but by just letting up on the gas. One owner told me you do it by finding a certain position on the gas pedal, but if true, it seems you'd have to go through some regen to get to that position

Ron

The pedal is a very precise thing in the i3, much more so than a traditional ICE car. I made a simple graphic to demonstrate:

Placing the pedal at exactly the coast/'neutral' point is precise and it is possible to come out of acceleration without going into regenerative braking. I wouldn't say it is hard. It is mechanically at the same point regardless of speed, incline, decline, traction, etc. so once you know where it is, you develop some muscle memory to adjust your foot appropriately.

 

[Jeffj]

I agree, I don't think its that hard to find the "coast" point, and once you've felt it, its pretty easy to find again. It may also help to watch the consumption gauge in the control display, as you hit coast when the white bar is right in the middle. Watching the display and subtly moving your foot shows you how sensitive the go-pedal is.

 

[GeorgeJ]

Please note when I started this thread I pointed out that I live in San Francisco. Nearly every day I am driving down a section of Filbert that is a 31.5% slope and other streets that are nearly as steep. I would not expect regen to stop the car on those hills. Just a thought though would it make sense for the initial travel of the brake pedal to dial up the regen strength and then start progressively adding friction braking?

 

[elptex]

Please note when I started this thread I pointed out that I live in San Francisco. Nearly every day I am driving down a section of Filbert that is a 31.5% slope and other streets that are nearly as steep. I would not expect regen to stop the car on those hills. Just a thought though would it make sense for the initial travel of the brake pedal to dial up the regen strength and then start progressively adding friction braking?

Note that when under regenerative braking, the pedal for mechanical/friction braking is pre-pressurized. There is virtually no brake pedal travel.

 

[BrianStanier]

Just a thought though would it make sense for the initial travel of the brake pedal to dial up the regen strength and then start progressively adding friction braking?

The Leaf does this and I suspect the many recent complaints about 'grabby' brakes comes from trying to blend friction and regenerative braking. I think BMW were wise to keep them separate.

 

[elptex]

I think BMW were wise to keep them separate.

Agreed!

 

[Stevei3]

Just a thought though would it make sense for the initial travel of the brake pedal to dial up the regen strength and then start progressively adding friction braking?

Hi,
my guess is that the i3 already does this: you see the recharge indicator increase when you brake a little with the brake pedal, even when the car is in 'N' while rolling.
Steven

 

[brandonmp]

Just got my BEV i3 on Wednesday, but I have been very happy with the regen, and have been mostly able to drive with one foot.

 

[Boatguy]

This thread has hopped around a bit, but after 5,000 miles and two s/w updates my experience is:

Regen and one pedal driving work fine. I could handle more regen, but my observation is that efficiency (i.e., mi/kWh) is optimized by more coasting, not more regen. Regen, like all energy transformations, is less than 100% efficient, it just can't convert the kinetic energy of the vehicle in motion into stored energy as efficiently as the car uses kinetic energy to coast down the road. In my regular routes I now know where I can switch to coasting, make it over a crest and then accelerate down a hill; all free distance traveled when coasting. With that in mind, I think they could widen the coasting band a little bit to make it easier to coast.

Regen does lighten up or turn off entirely at some inopportune moments. Another poster mentioned "hard cornering", which is relative. I consider hard cornering to be when I get close to loss of traction, like setting up a drift. But I can feel the regen back off much earlier than when I'm close to losing traction. Of course braking in the middle of a corner will cause an earlier loss of traction so I can understand what BMW was thinking, but the problem is that this is not under driver control, or entirely predictable. In mid-corner I feel the loss of braking as acceleration and while I know intellectually that it's actually improving my traction, I don't like the feeling of the car's behavior changing unexpectedly when I think I'm in control. A couple of times I've felt the loss of regen while cornering on a steep hill and it was very unnerving.

More to the OPs point, I also frequently drive in San Francisco, for example coming down from Pacific Heights to Lombard. That hill is quite steep and regen is not strong enough to control my speed, I have to also use the friction brakes. But in fairness to BMW, while those hills are steep, they are also very short and the amount of energy that could have been recovered from stronger regen over the course of 1/2 mile, versus what the current regen captures is inconsequential, particularly over the course of driving 40-60 miles in a day.

 

[WoodlandHills]

The Regen will also interrupt when slowing over rough pavement. There is a stop sign on a street with lots of potholes and patches just before the intersection that I must use the friction brakes to keep from coasting through. The Regen shuts off when the wheels are skittering over the patches......

 

[busaman]

The Regen will also interrupt when slowing over rough pavement. There is a stop sign on a street with lots of potholes and patches just before the intersection that I must use the friction brakes to keep from coasting through. The Regen shuts off when the wheels are skittering over the patches......

i noticed that yesterday when i was having a bit of a hustle up with an m3 v8 on country roads the regen would cut out on uneven and heavy braking over bump etc.(he was only 100yards in front after 4 miles)

i also noticed the when i was on full normal regen if you put pressure on the brake pedal the meter moves over another notch to hard left so im guessing applies a bit more regen.

 

[uktechie]

Noticed it can vary but the latest update was only meant to smooth it down a little eg when switching off cruise.

 

[kc1]

A BMW tech confirmed to me that Regeneration has indeed been reduced in software version I001-14-11-504, from 27 to 24 (I can't remember what he said the units were (kW-somethings per something I'm sure).

 

[i3Alan]

... I made a simple graphic to demonstrate:

Placing the pedal at exactly the coast/'neutral' point is precise and it is possible to come out of acceleration without going into regenerative braking. I wouldn't say it is hard. It is mechanically at the same point regardless of speed, incline, decline, traction, etc. so once you know where it is, you develop some muscle memory to adjust your foot appropriately.

Close, but not exactly correct. When you are at a complete stop, the "coast" point is all the way to the left, with no regen. As soon as you barely touch the pedal from a stop, you start accelerating, so you obviously must not be in regen in that very low part of the pedal arc. I believe the neutral (coast) point moves in a very non-linear way, accommodating the needs for acceleration or availability of speed to enable regen. Perhaps the neutral point of pedal position is fixed above a certain speed, such as 10 MPH, but it certainly is not at the same point for very low speeds.

I'm not sure what happens when you coast from a decent speed all the way to zero. Perhaps the coast point will not move in that case, or perhaps you will need to slowly let the pedal out as you approach zero speed to keep from going from a coast back to accelerating.

 

[S3RDP]

When I did the first i3 test drive a year ago in a BEV version I was impressed with the ease of one pedal driving. A few weeks ago when I did a three day test in a REX version it felt like I was getting a fair bit less braking from lifting off the accelerator. While some of this may be attributed to the additional weight I have heard that BMW did reduce the regen strength with a software update.

This is disappointing to read, a lot of my excitement for this car was the 1 pedal driving aspect.

This is disappointing to read, a lot of my excitement for this car was the 1 pedal driving aspect.

I still can usually operate with one pedal. Some of the new drivers complain that they cannot figure out how to drive the thing smoothly. I feel I could handle more, and having it adjustable, would be a nice option. But, I'm not sure the heavier regen, for most drivers, really produced more power back to the batteries...it certainly makes it more prone to a jerky driving style. The safest way to drive is to anticipate. I make it more of a game and try to avoid the brakes at all, with a combination of coasting and then gradual regen so I stop where I want to. There's no good reason to fly up to a red light and slam on the brakes, or have that max regen capacity.

Hi guys,
since the last s/w refresh that was installed in my car two weeks ago, I seem to have noticed that the regeneration has been tweaked a bit. It is my take that the regen itself is not reduced, it seems merely 'softened'. It sets in more gradualy when releasing the throttle, making it easier to drive smoothly. Since I've long ago internalized to gently ease of the throttle in stead of letting go like a in a 'normal' car, I need to recalibrate my right foot to ease off a little less gently and/or ease off a fraction earlier. No biggie, one-peadel driving is not in jeopardy. "Look ma, no brakes !"
Regards, Steven

A BMW tech confirmed to me that Regeneration has indeed been reduced in software version I001-14-11-504, from 27 to 24 (I can't remember what he said the units were (kW-somethings per something I'm sure).

Just picked up my new REx. First long drive - its awesome and exceeds even my high expectations. Having driven three demonstrators the regen on my 2015 car definitely feels smoother and I would guess it has been reduced a little but I actually found it easier to drive on one pedal. No snatching or sudden jerks so IMHO the software tweak adds to relaxing refined nature of car.

 

[Schnort]

I just got my car updated, and here's my thoughts:

I don't think they lessened regen, exactly, but it does let up when the car is near stopping, so it coasts a lot further at a slow speed than it used to.

I find this irritating because you can't rely on it to be your brake in stop/go traffic.

Of course, this is just my thoughts after driving back from the dealership.

 

[jadnashuanh]

Someone said that the programming logic had the max regen changed from a value of 27 to 24, so about 11% less, and probably the logic on when it was applied. I haven't tried to verify this, but feel that it did change. It is easier to drive smoothly, not that I had a problem after owning the car for a couple of days, it is true for a first timer.

 

[stumbledotcom]

Put me in the regen has been reduced camp. I've gone down a couple of very steep streets here where the car actually speeds up a few MPH even though I'm completely off the accelerator pedal. Prior to the update the car would hold a steady speed with zero accelerator going downhill on those same streets. I'm stepping on the brake pedal a lot more now.

I definitely do not like this new behavior.