WARNING: Please wear glasses in the unlikely event of a car or deep cycle battery explosion and save your eyes.
If done incorrectly, jumping a dead battery can be dangerous and financially risky. These procedures are ONLY for vehicles are that are both negatively grounded and the electrical system voltages are the SAME. These procedures would also apply to using emergency jump starters. DO NOT jump a frozen battery and ALWAYS connect POSITIVE to POSITIVE and NEGATIVE (-) to the ENGINE BLOCK or FRAME away from the dead starting battery. Reverse this rule to disconnect. The American Automobile Association (AAA) estimates that of the 275 million vehicles that will traveling in the U.S. during the Summer of 2003, 7.4 million (or 2.7%) will break down. Of that number, 1.3 million (or 17.7%) will require a battery jump to start their engine. The German automobile association (ADAC) estimates that their battery related service calls has increased from 21.7% per year in 1999 to 29.9% in 2004.
In cold weather, good quality jumper cables (or booster cables) with at least eight-gauge wire are necessary to provide enough current to the disabled vehicle to start the engine. Larger diameter, smaller gauge number wire is better because there is less voltage loss. Please check the owner's manual for BOTH vehicles or jump starter BEFORE attempting to jump-start. Follow the manufacturers' procedures, for example, some vehicles should not be running during a jump-start of a disabled one. However, starting the disabled vehicle with the good vehicle running can prevent having both vehicles disabled and provides a higher voltage to the starting motor of the disabled vehicle. Avoid the booster cable clamps touching each other or the POSITIVE clamp touching anything but the POSITIVE (+) post of the battery, because momentarily touching the block or frame can short the battery and cause extensive and costly damage.
In the event that the jumper or jump starter cables were REVERSED and there is no power to all or part of the vehicle, test the fusible links, fuses, circuit breakers, battery, charging system and emissions computer and, if bad, reset or replace. Their locations and values should be shown in the vehicle's Owner's Manual. If replacing the faulty parts do not repair the electrical system, having it repaired by a good auto electric repair shop is highly recommended.