Has regen been reduced

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GeorgeJ

Member
Joined
Aug 22, 2014
Messages
22
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. Do some of the better informed folks know the full story.

What I would like is the ability to dial up the regen strength for my day to day driving in San Francisco where the hills demand the use of the brake pedal and perhaps dial it back a bit when out on the road or on flatter terrain. I imagine this might be an issue with regulating agencies as the mileage data needs to be calculated based on a fixed set of parameters. I was not so disappointed that I did not go ahead and lease one.
 
Regen is somewhat variable based on the battery condition, but to keep from overcharging the battery, it will switch to the brakes themselves from what I hear. I don't live on top of a hill where I might test that possibility. Plus, the regen does vary based on traction and when turning which could compromise stability...it's pretty consistent when just moving straight ahead, though. I felt that the regen may have been (slightly) dialed back when they did the last s/w update, but it's hard to measure exactly.
 
yea i noticed that the brake regen kicks off if i hit a bump or a rough patch

or during hard cornering which can be surprising if im counting on that auto slow down


its gonna take some getting used to

:geek:
 
GeorgeJ said:
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. Do some of the better informed folks know the full story.

I test drove an early production BEV and now have a REX. No discernible difference from me. It is so variable based on many dynamic variables anyway. Regarding hills, where I live, I regularly go down a 9% grade and the regen can bring the car to a complete stop if I want. That's pretty strong regen braking.

What I would like is the ability to dial up the regen strength for my day to day driving in San Francisco where the hills demand the use of the brake pedal and perhaps dial it back a bit when out on the road or on flatter terrain. I imagine this might be an issue with regulating agencies as the mileage data needs to be calculated based on a fixed set of parameters. I was not so disappointed that I did not go ahead and lease one.

The Tesla Model S has an option to vary the regen strength, so it isn't a regulatory issue.
 
<<What I would like is the ability to dial up the regen strength >>
<<The Tesla Model S has an option to vary the regen strength>>

The VW e-Golf has 5 levels of regen which are set by the shift lever position: D (none), 1-3 (tapping shift lever l or r), and B (max which comes close to the i3).

Maximum range and mpg comes with D setting no regen, anticipating and coasting as much as possible, and using the brake for regeneration for the last 10-20% to stop. (There's no brake pad to metal unless you emergency brake). There's more footwork required, more time, and it's not as much fun, but if you're trying to squeeze the most range for a trip, it's the way to drive

Ron
 
I have noticed if you just touch the brake pedal that regen increases before the brakes take effect
 
Lincsat said:
I have noticed if you just touch the brake pedal that regen increases before the brakes take effect

Anecdotally, I've thought the same though wasn't quite sure if it was just the brake/power indicator or actual engagement of the physical brakes.
 
Unfortunately, regen strength has been reduced at least on the BEV i3.

How do I know this ? I've driven an early i3 and a newer 2015 i3. The difference whilst in EcoPro+ is massive between the two.

I'm sure it can't be beyond the wit of man for them to give the driver the option to select the strength of regen, in the iDrive menu?

Hey BMW - I want my strong regen back!!

Who's with me?
 
SSi3 said:
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.
 
As Discussed at

https://www.facebook.com/groups/BMWi3/permalink/796777493729447/

Please use M Laptimer App to record regen to 0. You will find G-Force recorded there. It should be .18 G until the the very low km/h or mph are reached. There is a discussion about this in goingelectric forum and you can compare the values you measure with the values noted there. With software I001-15-03-501 it should be .18 G until 4 km/h, so it is still normal regen and only reduced to the last meters to make a soft stop.

To add to the discussion, the tech docs (which predate all those updates) mention that the maximum deceleration under regen is 1.6m/s^2 which is..... 0.163g (Doc 4, page 48)
So .17 to .18g really seems right on spec. It's possible that BMW changed some operating strategy under certain conditions (it seemed that a lot of us noticed differences with the "Customer Care" update last year; wider coasting band, EcoPro is more smooth slowing down than Comfort) but I would say that the "max" regen probably hasn't changed.
I have to say that I am impressed with those who can tell regen is weaker/stringer. It seems that the car adapts so much to road condition and battery status that how much regen I seem to get vary day to day.
 
I could be wrong, but I think that deceleration under regen is less with extra passengers in the car. When driving on my own it seems easier to achieve a brake-free stop in the same conditions that require brake application with passengers on board.
 
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
 
SSi3 said:
This is disappointing to read, a lot of my excitement for this car was the 1 pedal driving aspect.

Don't be. You can absolutely 1 pedal drive. I haven't touched my brake pedal in 3 weeks (74 mile daily commute, 50/50 highway/non-highway). Last time I used it was to not hit a deer that jumped across the road (deer and car just fine :) )

At the risk of offending people, I think people fail to process that the regen braking is very intelligent and disengages/adjusts dynamically based on road conditions. If you are on a very undulating road, going over bumps, railroad crossings, turning sharply, loss of traction, etc. then the regen braking dynamically reduces. Traction sensors are incredibly sensitive these days so hitting puddles, standing surface water (even minimal), etc. all affect traction. BMW has clearly opted to ultimately keep the driver in control. 99% of the time the regen braking will take car of stopping needs, but even with sophisticated sensors and clever algorithms, ultimately if traction is in question, you, the driver, are best equipped to determine whether or not braking is required.
 
cove3 said:
I don't understand how you can coast to a full stop without having any kind of regen whatsoever take place.

In the same way you could take an ICE car, take it out of gear and let it coast. Rolling resistance will make it coast to a full stop on level ground.
 
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