A question about jump-starts

[swiss]

So this business with me alternator has got me thinking*. When me and Swiss' Missus got back from the States her battery had gone to pancake country, necessitating a jump from mine. Having never done so before I followed diligently the destructions in my HBOL. This had me connect red to red and my negative to an earth on her engine block (I used a stud which secures part of the trim).

Absolutely nothing happened. A friend of mine who was present phoned her old man who happened to be a car doctor and he advised me to go red to red and black to black. Wifey's car spluttered in to life and all was good once more.

It seems to me that following the Haynes method would connect the batteries in series while the second method would connect them in parallel. My question is which is correct? The AA website agrees with Haynes, so was I doing it wrong?


* I'll let someone else do the 'did it hurt?' joke

[mjb]

You wouldn't be connecting the batteries in series unless you disconnected the bad battery negative and put it on the good battery negative, then linked the good battery positive with the bad battery negative

It sounds like in your first attempt you didn't connect the good battery negative to an earth. "stud which secures part of the trim" doesn't sound like a good earth to me - I'd have gone for the gearbox, an engine lifting point, or simply just the battery negative as you later did

[jasper5]

Yeah, battery to battery, red to red, black to black every time, unless the terminal is difficult to access, then an engine or gearbox earth point.

A word of warning, if you jump start one of the later type vehicles, check in the handbook about jump starting...some cars will get seriously damaged by jump starting them.

[swiss]

Roger, thanks peepls.

So with my dicky alternator, am I just running on what's in the battery? Is it just a matter of time until it fails to turn the starter? Replacement is on order but I'm gonna have to do at least one commute before I can get it installed...

[omega]

when you jump start a car you should go pos to pos then neg to good earth on flat car, as said before a engine lifting eye is a good place
if you go neg to neg its harder to start the flat car as you have the resistance of the flat battery to overcome,you also have a greater chance of doing some damage to the ecu etc with arking

[HimBigChief]

If your alternator is goosed, then yes you will be running on what's in the battery, so best to use as little electrical equipment as possible. It's just a matter of time until the battery will be too flat to either start the car, or it may run out of juice mid commute, hence stalling and not being able to start again due to lack of electrical power.

[jasper5]

when you jump start a car you should go pos to pos then neg to good earth on flat car, as said before a engine lifting eye is a good place
if you go neg to neg its harder to start the flat car as you have the resistance of the flat battery to overcome,you also have a greater chance of doing some damage to the ecu etc with arking

What works, works.
Personally, I've been using red to red and black to black for the majority of my life in the car repair trade (39 years), I don't remember any problems.I think you will find the majority will use that method, but as I said, what works, works.

[swiss]

Well, at least being a dieso I don't have to worry about spark plugs... AFAICS it'd be a case of 'oh sh*t, my blinkers won't work'... I'm certainly not driving it in the dark just in case my beams conk out ^^

For the time being I've also disconnected the toaster, Playstation and 50" plasma...

[omega]

What works, works.
Personally, I've been using red to red and black to black for the majority of my life in the car repair trade (39 years), I don't remember any problems.I think you will find the majority will use that method, but as I said, what works, works.[/quote]

yes this way does work but its the old way now you are taught the way i said i think its because there is more electrical equipment on cars.if you look in most owners manuals[406 d9 page 131] it tells you to do it this way

[jasper5]

A word of warning, if you jump start one of the later type vehicles, check in the handbook about jump starting...some cars will get seriously damaged by jump starting them.

I'm happy to report that we agree after all

[teamster1975]

[Doggy]

Well, at least being a dieso I don't have to worry about spark plugs... AFAICS it'd be a case of 'oh sh*t, my blinkers won't work'... I'm certainly not driving it in the dark just in case my beams conk out ^^

For the time being I've also disconnected the toaster, Playstation and 50" plasma...

Unfortunately you do need to worry about your stop solenoid......

[swiss]

Ah, good point... so without power that'd kick in and kill the fuel?

[Doggy]

zactly