E90Post
 


The Tire Rack
 
BMW 3-Series (E90 E92) Forum > BMW E90/E92/E93 3-series General Forums > Regional Forums > UK > UK Technical Forum > Battery disconnect



Reply
 
Thread Tools Search this Thread
      03-23-2009, 09:44 AM   #1
paulcurtis
Private
11
Rep
52
Posts

Drives: 120d/320d Msport e91
Join Date: Jan 2009
Location: Kent

iTrader: (0)

Battery disconnect

Hi all,

I've not found a definitive answer for this yet, so im hoping someone can help.

If i disconnect the battery (key out) then what will I loose when the battery is reconnected?

Do systems need to be initialised?

The car radio unlocked? (I have no idea what the code is, the car is 2nd hand)

just wondering before i do it!

cheers
paul
Appreciate 0
      03-23-2009, 10:44 AM   #2
FotiosF90M5
///M Specialist South Shore BMW
FotiosF90M5's Avatar
United_States
801
Rep
7,109
Posts

Drives: 2021 M5 Comp BHG/Silverstone
Join Date: Jan 2007
Location: South Shore, MA

iTrader: (62)

the ONLY thing you lose it the time and date. i think mpg and that sort of thing too.
__________________
2021 M5 COMPETITION LCI Brands Hatch Gray on SIlverstone, carbon roof, comp wheels, Mperf splitter, carbon pro spoiler, carbon diffuser , carbon paddles, executive pkg. Dinan HAS, RaceChip, dinan spacers, FC stud kit, etc
Appreciate 0
      03-23-2009, 12:39 PM   #3
F104
Captain
Belgium
19
Rep
732
Posts

Drives: E92 320D M-sport
Join Date: Apr 2008
Location: belgium

iTrader: (0)

Quote:
Originally Posted by fotios335i View Post
the ONLY thing you lose it the time and date. i think mpg and that sort of thing too.
indeed that's all you loose. Do not disconnect the battery while the light in the starter button is still on, the ECU will be pulling 4 Amps while the light is on (about one minute). Then current draw drops (forgot to how much) and after 30 minutes from closing the door it drops to 40 milli-amp or less. So best is to take out trunk light, leave trunk open, close door, wait 30 minutes, and then disconnect it
Appreciate 0
      03-23-2009, 12:48 PM   #4
FotiosF90M5
///M Specialist South Shore BMW
FotiosF90M5's Avatar
United_States
801
Rep
7,109
Posts

Drives: 2021 M5 Comp BHG/Silverstone
Join Date: Jan 2007
Location: South Shore, MA

iTrader: (62)

I just disconnect it...lol
__________________
2021 M5 COMPETITION LCI Brands Hatch Gray on SIlverstone, carbon roof, comp wheels, Mperf splitter, carbon pro spoiler, carbon diffuser , carbon paddles, executive pkg. Dinan HAS, RaceChip, dinan spacers, FC stud kit, etc
Appreciate 0
      03-23-2009, 04:06 PM   #5
SoCalTech
Captain
United_States
24
Rep
648
Posts

Drives: Not a BMW yet...
Join Date: Oct 2008
Location: Redondo Beach, Ca

iTrader: (0)

Active steering will need to be initialized.
Appreciate 0
      03-23-2009, 04:46 PM   #6
SoYank
Major General
SoYank's Avatar
United_States
584
Rep
7,519
Posts

Drives: 2009 E90 335i MT
Join Date: Mar 2006
Location: Vinton, Virginia

iTrader: (1)

Garage List
Quote:
Originally Posted by F104 View Post
indeed that's all you loose. Do not disconnect the battery while the light in the starter button is still on, the ECU will be pulling 4 Amps while the light is on (about one minute). Then current draw drops (forgot to how much) and after 30 minutes from closing the door it drops to 40 milli-amp or less. So best is to take out trunk light, leave trunk open, close door, wait 30 minutes, and then disconnect it
Aha! So THAT's how the dealership can get away with charging an hour's labour for a thirty minute job.
__________________
2009 E90 335i Montego Blue · Black Leather · Burl Walnut · 6MT · US Spec
SatNav • ZPP • ZCW • 6FL • TPMS • iDrive • PDC • HWS • Xenons • BMW Assist • Power Rear Sunshade • Logic 7
European Taillights • Rear Foglamp • OEM Alarm • PicoTray • DataToys XM-DVR • Multi-view Processor
Quaife ATB LSD • Short Shift Knob • Hartge Anti-Roll Bars • AP Racing Front Brakes • 19" Style 269
Appreciate 0
      03-23-2009, 04:50 PM   #7
FotiosF90M5
///M Specialist South Shore BMW
FotiosF90M5's Avatar
United_States
801
Rep
7,109
Posts

Drives: 2021 M5 Comp BHG/Silverstone
Join Date: Jan 2007
Location: South Shore, MA

iTrader: (62)

Quote:
Originally Posted by F104 View Post
indeed that's all you loose. Do not disconnect the battery while the light in the starter button is still on, the ECU will be pulling 4 Amps while the light is on (about one minute). Then current draw drops (forgot to how much) and after 30 minutes from closing the door it drops to 40 milli-amp or less. So best is to take out trunk light, leave trunk open, close door, wait 30 minutes, and then disconnect it
whats the reason for doing this. im curious. thanks
__________________
2021 M5 COMPETITION LCI Brands Hatch Gray on SIlverstone, carbon roof, comp wheels, Mperf splitter, carbon pro spoiler, carbon diffuser , carbon paddles, executive pkg. Dinan HAS, RaceChip, dinan spacers, FC stud kit, etc
Appreciate 0
      03-24-2009, 02:08 PM   #8
greatbm
Major
greatbm's Avatar
United Kingdom
154
Rep
1,068
Posts

Drives: G15 840i Coupe
Join Date: Feb 2007
Location: North East

iTrader: (0)

Quote:
Originally Posted by fotios335i View Post
whats the reason for doing this. im curious. thanks
A charging battery gives off explosive gases, whilst under load the disconnection will draw an arc and could ignite causing explosion. As the battery is in the boot BMW vent the battery via a small pipe to under the car. It is just good practise to dissconect this way.
__________________
G15, 840i M Sport
Appreciate 0
      05-15-2009, 04:21 PM   #9
CdnE90
Second Lieutenant
15
Rep
226
Posts

Drives: 07 335i, 11 X3 x35 (on order)
Join Date: Jul 2008
Location: Canada

iTrader: (0)

Quote:
Originally Posted by SoCalTech View Post
Active steering will need to be initialized.
How does one go about doing this? Can I do it, or do I need to take it to the dealer?
Appreciate 0
      05-15-2009, 08:42 PM   #10
SoCalTech
Captain
United_States
24
Rep
648
Posts

Drives: Not a BMW yet...
Join Date: Oct 2008
Location: Redondo Beach, Ca

iTrader: (0)

Dealer only.
Appreciate 0
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 01:07 PM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST