Hello there and welcome to the BMW Car Club of America.

If you are a BMW CCA member, please log in and introduce yourself in our Member Introductions section.

Battery Disconnection & Saving Settings

Discussion in 'E81/E82/E87/E88 (2004-present)' started by jbasedow30, Jan 22, 2009.

    jbasedow30 guest

    Post Count: 6
    Likes Received:0
    I have a 2009 1 series with Idrive and am contemplating doing a couple DIY tasks (i.e. alarm, audio) that will require me to disconnect the battery. My question is what does everyone do/use to keep from losing settings/prefs? Do those 9v "settings savers" work? or would I have to connect a battery charger to the terminals in the engine bay? Thanks in advance for your advice/suggestions.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    Connecting a battery charger is the best way, but dangerous, as you then have a floppy loose powered up positive battery cable which, if grounded, can cause major damage. A 9V battery will not be able to keep the car powered for long because of all the crap on the car.
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    WAIT! Did you say alarm?!?! DON'T DO IT! Do not install an aftermarket alarm system on this car. Get the facotry one or don't bother. Nobody can steal your car without your key anyhow, unless they have a flatbed, and most people don't pay attention to a car being "towed" anyway. I have had to repair soooo many cars with crappy aftermarket alarm systems causing everything from blown fuses to the car dying randomly, to the whole car staying powered up with the key out of the ignition. Your car is so amazingly complex that tapping into one wrong wire can cause major headaches and will absolutely void your warranty. Audio stuff is more straightforward, but there is not much wiggle room on the new cars with everything being tied into the car's computers and all. Proceed with caution, here be dragons! I hope you are a professional. I mean a real pro, an not a stereo installer that thinks there are only 2 lengths of screw (4 inches and 6 inches) and do stupid crap like mount amps to Mercedes gas tanks with drywall screws (I have seen this many, many times from many "professional" shops.)

    jbasedow30 guest

    Post Count: 6
    Likes Received:0
    Thanks for the replies moosehead

    Would a 12v in the cig lighter work? Does your shop use the charger method? I assume I can just disconnect the negative battery cable and wrap a towel around it...

    What all would I end up losing? The manual states quite a few things, but I hear a range from just clock, to everything...I assume it has to do with how long one has the battery disconnected.

    Yes, I'm trying to install the factory alarm...Def wouldn't go aftermarket. Regarding the audio...I have the analog (non-premium) system...My goal is just to swap the amp and give the speakers a little more power (70 watts vice the 25)...Although, I prob. won't have the courage to do it and will end up taking it to a pro..
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    You know, I just pulled my head from my tuckus. Pulling the battery is basically so you don't short anything out, right? Well, if you still put power to the car, then you can still short it out, right? So it would seem that you have no choice but to pull the power for the duration of your fiddling. It won't really erase anything other than the time anyway. Here's a tip, though. Do not pull the battery with the key anywhere near the car. Let the car go to sleep for 15-30 minutes before pulling the negative battery cable (open the trunk if that is where the battery is, open whatever windows you will need, the leave the car alone completely for a while before pulling the cable.)

    mac townsend guest

    Post Count: 95
    Likes Received:0
    • Member
    • Technical Service Advisor

    mooseheadm5

    Post Count: 1,880
    Likes Received:15
    mact,
    you don't have a brand new 135i with an electronically coded key, do you? No. You have an E30 that I could steal in 10 minutes without damage, 30 seconds with.

    mac townsend guest

    Post Count: 95
    Likes Received:0
    if it took you longer than a minute I would be disappointed.<G>

    no door lock, BAM BAM for the igntion, gone. (I guess, I'm not in that habit< so don't know the tricksG>

    BUT...who would want to now...obvious thru the windows that there is a busted dash, no radio, busted top surround on the steering column. Someone's been there and gotten the goodies before you, dude. move on!

    in a way, THAT is the ultimate theft protection. "ain't worth your trouble, bro!"

    I have had browsers go thru the glove box once or twice and dump the mostly papers on the floor. they missed the cheapo GPS on the floor in the back.

Share This Page