Is this risky when jump starting?

colly10

Ive read about jump starting a car and all the advice seems to say not to connect the negitive terminal on the good battery to the negitive on the bad.

They all say to connect to shiny metal on the car to use it as a ground point. Do most people do this, never seen anyone doing this?

Is it very risky to connect the negitive poles?

CiniO

colly10 wrote: »

Ive read about jump starting a car and all the advice seems to say not to connect the negitive terminal on the good battery to the negitive on the bad.

They all say to connect to shiny metal on the car to use it as a ground point. Do most people do this, never seen anyone doing this?

Is it very risky to connect the negitive poles?

Did you see any explanation why would it be better to connect to "shiny metal" instad of directly to battery negative terminal?

Kenny Logins

Gas from the battery could ignite/explode with the spark created when connecting. Never heard of it happening though..

Kenny Logins

https://www.youtube.com/watch?v=d_TnsHu2u4c

GE90

As above, hydrogen gas can build up around the battery all it takes is a spark. It is very rare that it will result in a explosion but your better of not finding out. We all know what happened the Hindenburg.

GTE

CiniO wrote: »

Did you see any explanation why would it be better to connect to "shiny metal" instad of directly to battery negative terminal?

"Ditto" have been quicker :P


OP, I have often wondered about this. Although I can't remember which end they mean, the Haynes manuals say to connect a negative to a suitable ground on the cars chassis, which is where the shiny metal part of what you heard is coming from. I have always found it difficult to know exactly where a suitable place is to do that on my car, but I have not had a need to find out yet thank God.

GE90

bbk wrote: »

"Ditto" have been quicker :P


OP, I have often wondered about this. Although I can't remember which end they mean, the Haynes manuals say to connect a negative to a suitable ground on the cars chassis, which is where the shiny metal part of what you heard is coming from. I have always found it difficult to know exactly where a suitable place is to do that on my car, but I have not had a need to find out yet thank God.

Any bare metal will generally do. Head of a bold, lifting hook ect. It can be tricky with more modern cars with all the plastic panels covering everything.

SCOOP 64

Always just connected earth to earth on battery, because awkward to find any good earth on body,never had any trouble.

garclo

I've always just connected both leads from battery to battery, always thought that's what was supposed to be done. is this wrong?

naughtysmurf

I was told to connect the negative lead to chassis on more modern cars as it offers more protection to the ecu, don't know how true it is though

Greyfoot

I also heard the ECU problems but never experienced. I`m on the chassis, usually around strut bolts but my colleagues always do on battery.

dgt

Kenny Logins wrote: »

Gas from the battery could ignite/explode with the spark created when connecting. Never heard of it happening though..

Yeah that happens generally when the gasses don't vent while you have it charging. It explodes and leaves a huge grey mess everywhere.

I jump start a tractor the whole time with a 535i, positive to positive, negative to negative. No problems whatsoever

pajo1981

+1 because gas.

From a circuit POV it makes zero difference - the stuff about the ECU is clueless bollocks.

cml387

It's difficult to believe that in the open air a very light gas like hydrogen would be around in sufficient concentration to cause an explosion.

Any jump start I've done has been terminal to terminal. Best to concentrate on getting the polarity right!

Kenny Logins

cml387 wrote: »

It's difficult to believe that in the open air a very light gas like hydrogen would be around in sufficient concentration to cause an explosion.

Any jump start I've done has been terminal to terminal. Best to concentrate on getting the polarity right!

Look at the video above.

As I said though, never heard of it actually happening.

Esel

I always put the clamp on a chassis/engine point for safety.

biko

Had a quick google there and found one (1) incident, and it was a fire caused by a jump start.