How to Tell That an Alternator Battery Is Going Bad
When an alternator battery goes bad, it often does not give you any warning signs. The car will still run for a short time due to the amount of charge that is left on the car's battery. Without the alternator continuously recharging the car's battery, the battery will run out of charge and become non-operational, possibly leaving you stranded.
Supply List
- Hydrometer
- Standard flathead screwdriver
- Remove the negative battery cable from the battery.
- Use a flathead screwdriver to pry the battery cell cover from the negative battery post.
- Purchase a hydrometer that is designed for the size of the engine in the car. There are different hydrometers for different size engines. Match up the amount of cylinders in the engine to the amount stated on the hydrometer.
- Use the hydrometer according to the manufacturer’s directions for use. There is a syringe that will remove fluid from the battery and show you how many cylinders are firing on the car.
- Charge the battery if it is dead and start the car. Allow the car to run while the headlights are on. Watch the headlights to see if they appear to flicker or get dim. If the alternator is not functioning properly then the lights will become dim as the car is running.
- Turn on other devices inside of the car such as the radio and heater and check to see if this action causes the lights to dim. If turning on other electronic features that pull from the battery causes the lights on the car to dim, this is a sign that the alternator battery is going bad.