Jumper Cables
2008-09-18 17:25:00
Many motorists carry jumper cables which consist of a pair of heavy gauge insulated wires with alligator clips at each end. Jumper cables are marked by black (-) and red (+) handles, representing the two polarities of the automobile's direct current system. Interchanging the polarities will cause a short circuit and a hazard to people and damage to one or both automobiles. Good quality jumper cables will have large copper conductors and well-made alligator clips, and insulation that remains flexible at low temperatures. Longer cables require less maneuvering of the boosting vehicle to allow connection of the two batteries.
An alternative to jumper cables is a cable used to interconnect the 12 volt power outlets (cigarette lighter outlet) of two vehicles. While this eliminates concerns with incorrect connections and generation of arcs near battery terminals, the amount of current available through such a connection is small. This method works through very slowly charging the battery, not through providing the current needed for cranking. Engine cranking should not be attempted as the starter motor current will exceed the fuse rating in a cigarette lighter outlet. Many vehicles made since 1990 switch off the cigarette lighter outlet when the engine is stopped, making the technique unusable.
