[lunlun]

[CoryB]

Open the boot. Lift the boot mat and board. That's where the battery lives. Disconnect the negative terminal first (corrected as per numerous posts).

That should pretty much do it.

[kapps]

Red (positive?) first? I've always thought that the negative should always be disconnected first and re-connected last.

[lunlun]

so>!>!>!>! which one first!?

[mk20116]

Quote: Originally Posted by kapps

Red (positive?) first? I've always thought that the negative should always be disconnected first and re-connected last.

disconnect live(red) then disconnect ground(black). to reconnect, ground first then red.

[Mike Clarke]

The Owners Handbook - we did all get one with our cars didn't we?

Page 122 - Battery

"Before undertaking any work on the vehicle's electrical system, disconnect the lead from the NEGATIVE terminal of the battery in order to avoid the risk of short circuits and fire or injury"

[lunlun]

oh soryr~ i have 04 mcs

and the owner's manual doens't have that

"Before undertaking any work on the vehicle's electrical system, disconnect the lead from the NEGATIVE terminal of the battery in order to avoid the risk of short circuits and fire or injury"



but wait..>~>

so do i just disconnect the negative terminal??

or red first then black?

[lunlun]

there is this red cover thing ~~for the red terminal

do i unscrew the two screw under the cover?!

[EBMCS03]

Either one is fine... as long as one of them is disconnected... theres no power already wither either disconnected but I would usually disconnect the ground (BLACK) first... just unscrew it and pull it off from the battery... are you sure u want to work on your car what? rally lights when you're not even sure how to disconnect your battery? No pun intended but just a precaution...

[MICKEY]

Always do as the manual states........ Disconnect the EARTH terminal first.
In the MINI'S case that’s the negative terminal (BLACK)
If you try and disconnect the positive terminal first, you have a chance of your spanner slipping, allowing you to touch the positive terminal to the chassis (earth) which can cause a spark, this in extreme circumstances could cause the battery to explode.
When reconnecting the battery the EARTH terminal should be connected last.

As to do you need to disconnect both terminals? that depends on what you are doing, usually you can get away with just disconnecting the earth, that breaks the circuit so you won’t get any battery drain..

[sjbartnik]

ALWAYS disconnect the NEGATIVE terminal first. I once disconnected the positive terminal first (not on my MINI, this was years ago when I was dumber) because it was easier to get to. I'll never do that again.

The problem with disconnecting the positive terminal first is that if you accidentally short the positive terminal of the battery to anything metal around the battery (frame, body, what have you), you will have an amazing spark show at the very least. If you jump and let go of the implement that you've shorted, it can actually weld itself in place if it maintains contact between the battery and body. Or if you happen to be wearing a ring on that hand while holding the metal implement, you can get a nice burn. And we all know that car batteries vent hydrogen, and sparks are not a good thing to be producing around hydrogen. Battery explosions are rare events but they do happen and I don't know about you, but I don't want my face embedded with plastic shrapnel and sulfuric acid.

The one time I disconnected the positive terminal first, I was loosening the bolt that held the terminal clamp together when my wrench slipped and contacted part of the bodywork. Luckily for me all I got was the amazing spark show before I quickly jerked the wrench out of there. Then I called myself a few choice names for being such an idiot and learned from my mistake.

If you are merely disconnecting the battery to do some electrical work, there is no need to disconnect both terminals. Just the negative terminal will do nicely. About the only time you would need to disconnect both terminals is if you are removing and replacing the battery.

On the MINI, red is positive and black is negative (ground). But never ever go by just the color. Always look for the + and - markings on the battery near the terminal. I've seen plenty of cars where the cable colors are reversed. Going just by color can lead to some nasty surprises, especially when jump-starting.