What happens if I disconnect my battery?
12-14-2018, 09:01 PM
#1
Rennlist Member
Thread Starter
What happens if I disconnect my battery?
I want to permanently install battery tender connectors on the terminals, but on the negative side I'd need to lift the terminal off the post to get the spade connector on the nut. If I lose power, will I need to call NASA/Porsche/Bosch/MicroSoft to restart the car, or will it sort itself out on its own like nothing happened? I could probably rig up some wire to keep the car powered when I pull up the terminal, if really needed?
12-15-2018, 12:00 AM
#3
Rennlist Member
From my experience, nothing happens, I didn't even lose my radio stations or seat position.
One piece of advice, before you disconnect the battery, bring your windows down a smidge so you are able to open the doors without any issues. Also, I put a small piece of wood on the latch, just in case the frunk slams down it won't close.
One piece of advice, before you disconnect the battery, bring your windows down a smidge so you are able to open the doors without any issues. Also, I put a small piece of wood on the latch, just in case the frunk slams down it won't close.
12-15-2018, 09:06 AM
#4
Rennlist Member
I've done it and nothing changed. Everything worked as before.
12-15-2018, 09:50 AM
#5
Rennlist Member
Yep, I swap out my lithium battery on occasion, and the computers sort everything out. As Aft86 said, lower your windows and DO NOT LET THE FRUNK CLOSE. If you really want, you can get an OBD connector that keeps power to that stuff while you do your work. If you unexpectedly do find yourself with a closed frunk and no power, you have to get power to the car from the fuse panel on the drivers' side. You pull out the positive post that's buried within that fuse box, and you have to connect the negative to either the door hinge if it's unpainted, or some cars have a little unpainted stud way inside the door front edge that you've probably never noticed. If your hinges are all painted, you have one of those studs. Battery tender is a good idea.
Last edited by Randyc151; 12-19-2018 at 08:49 PM.
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12-15-2018, 12:25 PM
#8
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Thread Starter
Thanks all. I've read there is some ECU programming to do when replacing the battery. Does that not apply when you just briefly disconnect and reconnect your existing battery?
12-15-2018, 12:32 PM
#9
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12-17-2018, 12:00 PM
#11
I wired up my battery ( Ctek) few years ago. I just loosened up the nuts on both terminals without actually disconnecting them so no disruption in power to car. I trimed the rings of the tender terminals and just slipped them under the nuts of the terminals and tightened them back down. fyi, The negative terminal
of the charger does not have to be attached to the negative side of your battery. Just attach it up to an unpainted ( bare metal) body nut near there.
of the charger does not have to be attached to the negative side of your battery. Just attach it up to an unpainted ( bare metal) body nut near there.
12-17-2018, 03:03 PM
#12
Rennlist Member
Thread Starter
I wired up my battery ( Ctek) few years ago. I just loosened up the nuts on both terminals without actually disconnecting them so no disruption in power to car. I trimed the rings of the tender terminals and just slipped them under the nuts of the terminals and tightened them back down. fyi, The negative terminal
of the charger does not have to be attached to the negative side of your battery. Just attach it up to an unpainted ( bare metal) body nut near there.
of the charger does not have to be attached to the negative side of your battery. Just attach it up to an unpainted ( bare metal) body nut near there.
12-19-2018, 08:14 PM
#14
Burning Brakes
Yep, I swap out my lithium battery on occasion, and the computers sort everything out. As Aft86 said, lower your windows and DO NOT LET THE FRUNK CLOSE. If you really want, you can get an OBD connector that keeps power to that stuff while you do your work. If you unexpectedly do find yourself with a closed frunk and now power, you have to get power to the car from the fuse panel on the drivers' side. You pull out the negative post that's buried within that fuse box, and you have to connect the negative to either the door hinge if it's unpainted, or some cars have a little unpainted stud way inside the door front edge that you've probably never noticed. If your hinges are all painted, you have one of those studs. Battery tender is a good idea.
12-19-2018, 09:03 PM
#15
Rennlist Member
Thread Starter
https://bimmertips.com/bmw-battery-r...ing-explained/