How to jump start a car!

davetrousers

On the previous occasions I have jump started a car I have connected the red lead to the positive battery terminals and the black to the negative. However I have googled How to jump start a car and read a couple of pages that say connect the black wire from the 'good' battery to some exposed metal on the car with the dead battery rather than to the negative terminal on the battery.

Has anyone else heard this? What's the thinking?

Silk

Hi Dave,
The thinking behind it is that the dead battery will suck a certain amount of juice from the good battery.
If you by pass the old battery it saves most of the drain.
Realy depends on how flat the old one is as to how much of an advantage it can be

jaydeeuk1

I always thought it to be more about a danger of explosion from sparks. Don't batteries emit hydrogen gas?

epninety

It also assumes you are sensible about your choice of 'exposed bit of metal'.
If you use a decent point, ideally on the engine block near the starter motor, there is a definite advantage to be had.
If you choose (for example) a bracket bolted inside the front wing, it might well be worse than just using the battery negative terminal.

Hintza

I have tried this before and can never get a decent earth so it is back to the -ve terminal for me!