It always seems to happen when you're late. You turn your car's ignition and hear the dreaded silence of a dead battery.
The best option is to carry a self-contained battery jumper, said Lauren Fix, spokeswoman for the Car Care Council (carcare.org), a consumer education campaign. A portable jump starter can be juiced up in a wall socket and left in your trunk; it clamps onto the dead battery and delivers the charge needed to start a car. Many models cost less than $100.
Barring such foresight, find another car to give you a jump, which takes some knowledge of cable connections and battery health so you don't shock yourself or, in rare cases, cause an explosion.
Fix, an ASE (Automotive Service Excellence)-certified technician, describes how.
Important note: These instructions may not apply to all hybrid vehicles. If you have an electric or hybrid car, follow directions in the owners manual.
Degree of difficulty: Medium.
Tools required: A portable battery starter streamlines the process. Otherwise, battery cables, a volunteer car with a working battery, goggles.
Step 1: Pull the assisting car up to the dead car close enough so the cables can reach but not so close that the cars touch. Turn off headlights, blinkers, radios and heating systems, and unplug accessories from power sockets on the dead car.
Step 2: Pop the hoods. Locate the batteries in each car and identify the positive (+) and negative (-) terminals. Wear goggles to protect your eyes in case of explosion.
Step 3: Identify the jumper cables: Red is for the positive charge, black for the negative. The thicker the cables, the better the jump. Don't let the clamps of the opposing cables touch, or you may get a shock.
Step 4: Take the red jumper cable and affix one clamp to the positive post of the dead car battery. Affix the other clamp of the red cable to the positive post of the live car battery.
Step 5: Take the black jumper cable and affix one clamp to the negative post of the live car battery. Affix the other clamp of the black cable NOT to the negative post of the dead battery, but rather to an unpainted metal part of the dead car's engine block, such as a bolt. Otherwise you might get a jolt.
Step 6: Start the engine of the assisting car. Start the dead car. Once it cranks, leave it running for a few minutes to draw the charge from the good battery.
Step 7: With both cars running, remove the cables in the reverse order from which you placed them. (And take your car to get your battery checked.)
DO NOT attempt to jump a car if:
You smell gas or acid; see the battery leaking liquid or see an electrical spark; or the battery has come out of the battery tray. Instead, call a tow truck to take it to a technician.
Life Skill #10
Jump start a car battery
How to start a car when the battery has died.
Jump start a battery (Rick Tuma/Tribune illustration / August 24, 2011)