How to Use Jump-Leads!

Several people have mentioned that they don't know how to start a car safely, using jump-leads. Obviously this technique will never be needed on a Cortina, but here's how:-

First, ensure that the jump leads are well insulated and up to the job. Some leads used to be made of aluminium and were very inefficient. Copper is much more suitable.

I will call the vehicle providing the power the "donor" vehicle, and the one with the flat battery the "dead" vehicle.

Read through all the instructions first!

1) Check the polarity of the dead vehicle. If you get this wrong you can do severe damage to alternators etc.

2) Make sure the donor vehicle is switched OFF. Connect the jump leads to the donor vehicle. Make sure you understand the polarity. The positive lead goes to the positive battery terminal on the donor vehicle. The negative lead to negative.

3) Make sure the two ends of cable now in your hands DO NOT TOUCH. This will put a short circuit across the battery and can cause damage or even a fire. (You effectively have an arc-welder in your hands. First you get a big, fat, loud spark, then the ends will weld themselves together! Not recommended.)

4) Connect the live leads onto the dead vehicle's battery. Ensure correct polarity. Positive lead to positive battery, negative to negative.

5) Now start the engine on the donor vehicle and let it idle.

6) Now try to start the dead vehicle. If all is well it should start readily, unless there is another fault which is outside the scope of this note.

7) When the dead vehicle is running, disconnect the leads, first from the donor vehicle, then from the "dead" vehicle. Job done!

Home Page

Page created/updated:- 03 October, 2006