Replacing a Car Battery.... (not what you might think)

Egyptian

Hi.

Short Version:
I want to replace a car battery, without disconnecting power to the car.

Long Version
I have a pre 1996 Mini 1.3. The battery in it is nearly dead, and cannot be recharged. The car has a Clifford alarm system and immobiliser. I'm afraid if I disconnect the battery completely, then put in a new one, I'll lose all the coding for the alarm system, immobiliser, stereo, etc.

It does not have a cigarette lighter, so I can't use a simple memory saver. I'm wondering is it possible to do what I've tried to illustrate below?

I have 3 batteries. The original, the new, and a spare. Is it possible to...

1) Connect the spare battery to the positive and negative leads already connected to the original battery.
2) Then disconnect the original battery and remove it, so that the spare battery is still connected to the leads.
3) Install the New battery I want to use, and reconnect the leads to (while still attached the spare battery).
4) Remove the spare battery from the leads.


Many Thanks for any help on this question.




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colm_mcm

can't see any problem with that. just figure out where you can connect the leads so they won't move when you undo the battery terminals.

Egyptian

colm_mcm wrote:

can't see any problem with that. just figure out where you can connect the leads so they won't move when you undo the battery terminals.

That's the only thing I'm worried about, if the cables slip off, but hopefully they'll be clamped tight enough, and I'm going to try my best to keep them on while changing.


But all in all, it's possible? I had thought so, just wanted a few more opinions

pa990

umm... maybe if youchange the battery while the engine is running

daedalus2097

Noooooooo! Don't disconnect the battery with the engine running!!! While that would be fine for the engine itself, the sudden flood of noise from the alternator which is normally absorbed by the battery can damage sensitive electronics, such as your alarm, stereo, and ECU (not sure how advanced the ECU is on those Minis though, if it has one at all). Are you sure your stereo needs a code? and I'd imagine the alarm/immobiliser would keep its code, seeing as it should be able to deal with someone cutting power to it to steal the car. I have a Cobra alarm/immobiliser and it'll sound its siren as soon as you disconnect the battery, using a backup battery in the alarm system itself to keep it alive.

Mr.Diagnostic

There is an easier way. Use the spare battery to maintain supply by connecting the pos to the system at a different point away from the battery where it will not get in your way. There is a direct connection from the back of the altenator to the battery pos. Any earth point will do.
Remember the pos terminal at the battery will be live so use something to cover it and avoid it shorting against the bady while disconnected.

richie_rvf

You could use a battery charger - connect it to the leads in the car, remove the old battery, install the new, remove the charger.

Richie.

Egyptian

I was thinking that, but I have access to 2 batteries (work in halfords) , so I though I might as well to it this way.


EDIT

*UPDATE*

Well I decided to just take the battery out, and risk losing coding, alarm, immobiliser, etc.

But it went fine.

I took out the old battery, installed the new one..... the alarm went off, I turned it off using the remote, and everythings working fine now


Many Thanks for all your replies!