[Brennan]

Just wondering is there any problem using jump leads connected to the battery terminals of my e90 to jump start another car that has a flat battery?

My dad thinks the e90s have surge protectors or something like that (i wasnt really listening to him haha) so they wouldnt be any use to jump start a car

Just want to clear up this debate with him lol

[xenon]

You certainly can, but you're better of using the terminal posts designed for this purpose rather than connecting straight to the battery. Clearly described in the manual how to jump-start another car or to be jump-started yourself.

[Giff]

I only saw the first words of the thread title and got really excited..

[Brennan]

Originally Posted by xenon

You certainly can, but you're better of using the terminal posts designed for this purpose rather than connecting straight to the battery. Clearly described in the manual how to jump-start another car or to be jump-started yourself.

cheers mate, i knew my dad was wrong

[HighlandPete]

As said, use the under bonnet terminals and follow the correct procedure of connection/disconnection.

HighlandPete

[Brennan]

guys which are the terminal posts?

[m1bjr]

The one with the big red plastic cover is positive - near the drivers window wiper.
Clip the neg to anything solid on the bodywork nearby.

[Cafe.Racer]

Originally Posted by m1bjr

The one with the big red plastic cover is positive - near the drivers window wiper.
Clip the neg to anything solid on the bodywork nearby.

Didn't work for me when I ran the battery flat once. Under the Big Red plastic cover is the positive, but the negative connection is a special long hexagonal "bolt" on the inside of the wing near the driver's side headlight.

[Shadow]

Originally Posted by Cafe.Racer

Didn't work for me when I ran the battery flat once. Under the Big Red plastic cover is the positive, but the negative connection is a special long hexagonal "bolt" on the inside of the wing near the driver's side headlight.

This.

[doughboy]

Yep, its tricky to get a good neg/chassis connection on little 'stub' they provide.

It just too small for the largish croc-clips you get with cheap jump leads.

You're better grabbing some big (unpainted) metal chunk of engine block or similar then you can get a good grip with the clips.

[Jules59]

Probably teaching you to suck eggs, but connect up the positives first - from donor battery to your car, then connect up the negatives - from your car to the donor. That way if you accidently touch the body with the free cable end you wont short out the batteries and weld the cable to your car or worse.

[m1bjr]

Originally Posted by Cafe.Racer

Didn't work for me when I ran the battery flat once. Under the Big Red plastic cover is the positive, but the negative connection is a special long hexagonal "bolt" on the inside of the wing near the driver's side headlight.

What are you guys on?

You can connect to ANY bare metal part of the chassis / engine and get an earth connection.
I did this only last week as it happens, to jump a bike. Used one nut on the turret top IIRC.

[doughboy]

Originally Posted by m1bjr

What are you guys on?

You can connect to ANY bare metal part of the chassis / engine and get an earth connection.
I did this only last week as it happens, to jump a bike. Used one nut on the turret top IIRC.

Of course you can, you and I and others know that, but the 'official' ground stub is useless as said.

So anyone checking the manual (so not 100% with doing it anyway) will be shown a duff method.

Any nice chunk of unpainted engine will do

[Shadow]

Originally Posted by doughboy

Of course you can, you and I and others know that, but the 'official' ground stub is useless as said.

Any nice chunk of unpainted engine will do

I don't know what leads & clips you're using - Monster Cable?

Maybe the 'official' ground point is different on mine (about 1" long bright shiny hex?), but it seemed to make better contact. The problem end was the other car (elderly honda)...

[doughboy]

Just £10 halfords regular jump leads, but the croc clips are wider than the stud is long so they only catch one side of the jaws

The jaws also have spikes specifically designed to sink into soft lead battery terminals (which is what the honda would have had??), so on a hard surface they have minimal contact area.

On the two times i've tried to jump other peoples cars from mine, the stud was no use, it just sparked a lot and smoke came off the clamp jaws as they overheated.

[Shadow]

Originally Posted by doughboy

Just £10 halfords regular jump leads, but the croc clips are wider than the stud is long so they only catch one side of the jaws

Right - I've seen that type of clip; like you say, they work best if you can get them onto the softer battery terminals. They would have worked for the Honda except the leads my mate had were too short to reach his battery even with our cars parked 2" apart!

[m1bjr]

http://www.telegraph.co.uk/motoring/...ump-ahead.html

Why I don't use £10 Halfrauds crap leads