Jump Starting

ksebruce · 12-09-2007, 12:00 PM

In the hope this avoids damage to vehicles.

Do not ever connect the earth from battery to battery as this can cause damage to the Engine Management system!!

Always consult the vehicle manual.

The AA recommended method is:
Before connecting any leads make sure the vehicles are the same voltage and that they're parked with their handbrakes on and ignition off. The vehicles must not touch as this can cause sparks or an explosion.

Use the red jump lead to connect the positive terminal of the donor vehicle's good battery to the positive terminal of the flat battery.
Then use the black lead to connect the negative terminal of the good battery to a suitable earthing point on the engine or chassis of the other vehicle. This earthing point must be away from the battery and fuel system.
With both leads connected wait three minutes for the voltages to equalise before starting either engine.
Start the engine of the donor car and allow it to run for a minute then, with it still running, start the engine of the other car and leave both running at a fast idle for ten minutes. Do not remove the jump leads while the engines are running as this can cause serious damage to the electronics on either car.

If the jump leads get hot, then avoid a possible fire by switching off both engines and allowing the leads to cool.
Turn off the ignition on both cars and then disconnect the leads carefully in the reverse order to the way that they were connected. Be careful not to touch the clips against each other or against the car bodywork.

GeorgeTelford · 12-09-2007, 04:16 PM

Quote:

Originally Posted by ksebruce

Do not ever connect the earth from battery to battery as this can cause damage to the Engine Management system!!

Even if you connect from chassis to chassis for the negative it still connects one battery negative to battery negative.

Do not trust anyone who calls negative on a vehicle "earth", its the first clue that they have not got a clue what they are talking about.

Quote:

Originally Posted by ksebruce

The vehicles must not touch as this can cause sparks or an explosion.

Have they been watching to many American TV shows/films, in the real world cars do not explode on contact.

GeorgeTelford · 12-09-2007, 04:18 PM

PS this is not a dig at you Ken

RockieRV · 12-09-2007, 04:19 PM

Quote:

Originally Posted by GeorgeTelford

PS this is not a dig at you Ken

Hi George

I am glad you have said that, because your first post does read as if you are

Jim · 12-09-2007, 04:22 PM

Sharon, that's is George's writing style but we are slowly bring him around to using smileys, as much as he hates them

steve&barb · 12-09-2007, 04:22 PM

damn and there was me jump starting of me leisure battery

ksebruce · 12-09-2007, 04:34 PM

What I posted was the recommendations of the AA.

I had an XJ6 jag which was in the garage for service and an apprentice used it to jump another car off. The end result being it "fried" my engine management card. The garage replaced this at great cost. This prompted me to read the "manual" and Jaguar had a paragraph warning against used the "negative" terminal on the battery, but to attach the lead to the engine "body" I think they would know.

GeorgeTelford · 12-09-2007, 04:52 PM

BTW that AA guide does not allow for positive earthed vehicles, the look of surprise when people find out the hard way is priceless.

So be sure that both vehicles are negative earth first (in this case earth is the conventional term, unfortunately)

Just researched the reason for not using the negative terminal. Its to idiot proof the connection procedure, ie if you were to do it properly connecting via negative terminal would not be a problem with igition off....