GuyD
Posts: 29
Joined: Wed Jun 06, 2018 6:06 am

Regen and creep operation?!

Mon Dec 09, 2019 1:46 am

We have now had our i3 for well over a year and are generally very happy with it - it is now our 'go-to' car and the ICE cars languish in the garage. Charged from solar so we notice the savings!

The steering is much improved since we had the tracking/alignment done by BMW (rather than a tyre fitment place!)

I've recently noticed odd behaviour and curious whether others have had this experience. Sometimes when driving in traffic fairly slowly the regen seems to stop working (ie the car coasts rather than slowing) - this is not with a full battery. Catches me out as I've become so attuned to the regen.
The car sometimes creeps on zero throttle (and thumps when drive/reverse is engaged) so it seems that a bit of residual motor action is occurring on no throttle. BMW did reload the motor control software at the last service but this doesn't seem to have cured the quirk.

Any ideas/suggestions out there?

User avatar
MKH
Gold Member
Posts: 499
Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: Regen and creep operation?!

Mon Dec 09, 2019 6:31 am

Sometimes when driving in traffic fairly slowly the regen seems to stop working (ie the car coasts rather than slowing) -
Is the road at all rough/bumpy when this happens? The regen braking is designed to disengage to protect the drive components if the car hits a bump, dip, or turns sharply. I have a stop-sign near my house that I hit on an almost daily basis. There is a very slight bump/washboard coming up to it, and as one-pedal regen braking slows the car approaching the stop sign, the regen braking cuts out and the car coasts every time the wheels hit the bump.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

GuyD
Posts: 29
Joined: Wed Jun 06, 2018 6:06 am

Re: Regen and creep operation?!

Mon Dec 09, 2019 11:23 am

Thanks Mark for the input.

No it usually happens in traffic on smooth roads! I have noticed that if I lift off and slow on regen on a gravel road and there is any 'irregularity' , the rear wheels momentarily lock up or skid and then the regen licks out.

The fact that it also creeps and thumps into drive seems to indicate some elec supply to the motor with no throttle - this only occurs occasionally

Lesterbmwi3
Posts: 27
Joined: Mon Sep 25, 2017 12:32 pm
Location: USA- NewYork

Re: Regen and creep operation?!

Mon Dec 09, 2019 4:34 pm

I wash a rotors and calipers once a while to keep them dust free and hit brakes hard once a day to clean rust bc if you use only regen they rust bad and make creepy noise at least in my case try maybe you solve your problem brake pads should last “ forever”

User avatar
MKH
Gold Member
Posts: 499
Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: Regen and creep operation?!

Tue Dec 10, 2019 11:54 am

Wonder if you have a slightly loose/damaged suspension or drive train component, which is giving you the 'clunk' you hear when shifting, and moves just enough out of 'true' on occasion to have the regen braking disengage, but not enough to trigger the dreaded 'drive-train malfunction' error??
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

GuyD
Posts: 29
Joined: Wed Jun 06, 2018 6:06 am

Re: Regen and creep operation?!

Tue Dec 10, 2019 1:35 pm

That is an interesting thought re the loose suspension but I have just had the alignment done so surely they would have picked up a loose/damaged suspension part?

On the other hand since the alignment I have noticed an improvement in the steering but the car seems more sensitive to winds and road camber now....

Puzzling but not a major issue so far.

User avatar
MKH
Gold Member
Posts: 499
Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: Regen and creep operation?!

Tue Dec 10, 2019 1:53 pm

since the alignment I have noticed an improvement in the steering but the car seems more sensitive to winds and road camber now....
Maybe the result of a change in tire pressure? If the tires were low, and they added air during the alignment.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

GuyD
Posts: 29
Joined: Wed Jun 06, 2018 6:06 am

Re: Regen and creep operation?!

Wed Dec 11, 2019 7:51 am

I always keep the tires at 2.4bar front and 2.9 bar at the rear as advised by the BMW agent. Tires new at rear, still good at the front.

What is the expected tire life? I got just over 30k km on the rears and then they were done. Fronts on 33k kms and still good - 60-70% wear I'd guess.

Returning to the first query - I suspect somewhere in the motor controller, the motor is giving a couple of percent of power/eletron flow on zero throttle (occasionally) so nullifying regen at slower speeds; causing some creep and making the thump on engaging drive. Not a big issue for now. Just curious to see if it was commonplace.

jadnashuanh
Posts: 4766
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Regen and creep operation?!

Wed Dec 11, 2019 8:19 pm

The regen not only changes when it detects slip (that includes hitting a bump), it also is tied into the steering wheel angle, so the tighter the turn, the less regen will be produced. From a performance issue, braking in a turn can upset the balance, especially on a vehicle that is only driven by one axle and only one producing regen (braking). It's a good way to induce a spin if the surface isn't perfect. Think handbrake turns...
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

CanisLupus
Posts: 92
Joined: Thu Sep 15, 2016 10:48 pm

Re: Regen and creep operation?!

Thu Dec 12, 2019 7:57 am

Just a thought , could there be an issue with the pedal position sensing mechanism and/or electronics ?

Return to “Technical BMW i3 Discussions”