A car battery stores electric energy until it is used to power the starter motor, the lights and the vehicle's ignition. The car's engine powers a system that recharges the battery continually while the engine is running. Leaving your car's lights on after turning off the engine can drain the battery's energy in a matter of hours.
If your car is slow to crank, there's a good chance the energy level in your battery is low. You can check the level using a hydrometer or voltmeter, but some batteries have indicator dots that are green when the battery is more than 75 percent charged and black when the percentage drops below that level. If you are able to start the car at all, you can allow the engine to recharge the battery by driving around for about 30 minutes.
If your ignition doesn't make a sound when you turn the key, the battery might be very low or completely dead. If your console lights still come on, the battery is not completely discharged. You can recharge it using jumper cables and another car, or a battery charger.
Jumper cables draw the energy from another car's battery while the engine is running. Attach the cables to both batteries before starting the car, carefully following the directions that came with your set. Start the second car and let the engine run for 5 minutes. Then try to start the car that had the dead battery. If you are using a battery charger, attach its cables directly to the battery and turn the charger on. Again, the car should start after 5 minutes of charging time.
Recharge or Replace?
Recharging the battery will get your car running again in the short term, but if you find yourself recharging it again soon, or if it will not recharge at all, it's time for a replacement. The life span of a battery is three to five years under ideal conditions, but few experience ideal conditions. Driving mostly short distances, exposure to cold temperatures, and multiple battery discharges from leaving the lights on will all shorten the battery's life span. Most car owners need to replace batteries about every three years. If you are finding that recharging your battery doesn't help for very long, replace the battery.