Disconnecting Car Battery

sylonien · Post by **sylonien** » Wed Sep 22, 2004 11:47 pm

Hi.

Erm... I jus had an incident earlier on when I tried to disconnect the car battery to see how it's done, 'cos I'm planning to install the head-unit, amp, etc etc. and most places said I should unplug the battery first - for obvious safety reason.

But when I unplugged the Minus/Black/Negative lead, it sparked a little. s**t the hell out of course since it's high voltage and me being a novice not knowing what I'm doing, so I unplugged the Plus/Red/Positive lead, which was okay, but when I plugged it back in (Positive), it sparked again!

What am I doing wrong!? I dont' wanna die from an electrical shock now. Help!

david burton · Post by **david burton** » Wed Sep 22, 2004 11:54 pm

haha lol

it's just jumping the gap between the connector and the battery - it's completing the circuit.

do the negative then the positive lead. this ensures that there is no supply of current. yes it will usually spark - but it's not anything to worry about, and it won't hurt.

never connect the two sides of the battery direct - e.g. with a spanner - it'll tend to blow up!

GroovyCarrot · Post by **GroovyCarrot** » Thu Sep 23, 2004 7:43 am

Sparking's fine, it's a powerful battery, it just has enough power to jump a small air gap.
As david burton said, never short the two terminals.. doing it directly with a spanner will make it go 'bang' and doing it indirectly through the wiring loom will melt pretty much everything between the two terminals, as I found out the hard way

Also make a point of not touching any metal surfaces whilst in contact with the positive terminal, just in case you happen to stray onto a scratched / unpainted bit of metal and short the battery through yourself

sylonien · Post by **sylonien** » Fri Sep 24, 2004 3:16 am

Thanks guys.

Just let me get this one very straight.

1) Disconnect the negative with a normal spanner?

2) Then disconnect the Positive?

What about reconnecting it. Does it have to be in specific order? I'm really scared of that freaken battery.

No joke. And it is safe to use that spanner to tighten the screw on the battery terminal since currents are flowing through it? Would that liike get on to me?! Ahhhh....

david burton · Post by **david burton** » Fri Sep 24, 2004 9:24 am

hahah LOL

you have to _complete_ the circuit. you're not doing that with a spanner unless you touch a grounding piece of the bodywork too, and it'll be the spark that hurts (heat) not the current.

anyhow, when reconnecting, do the positive then the negative.

spanner is fine to use. don't tighten too much!

don't worry - this stuff isn't going to hurt. if you're worried, then don't touch the terminals, but tightening wont hurt at all - it's not flowing through you!

the only really dangerous stuff is the ignition system post-coil. that WILL hurt - try touching a HT lead's end!!!

sylonien · Post by **sylonien** » Fri Sep 24, 2004 4:28 pm

Right, thanks. I think I really have got the idea now.

Just making sure since I don't know anything about cars to be honest. Except driving it.

And touching that "ignition system post-coil" - no thanks. First I don't know even know where or what that is and if you said it will hurt, that's not a hell no.