Slow Engine Crank: When you attempt to start the vehicle, the cranking of the engine is weak and takes longer than normal to start.
You have Jumped start your car a Lot: If you have to jump your car more than three times in a single week, it’s time to replace your battery.
There are some devices on your car that are supposed to go to sleep when it’s parked, and sometimes, not all of them go to sleep.
Interior Electrical Systems Current Leak: Most vehicles draw some battery current when the key is off, example clock and the internal memory of engine computers, body-control modules and radio presets. All these together draw a very small amount of current. Fifty milliamps would be a safe upper limit for this, although many vehicles will draw less. If you’re not sure, look up the correct rating in the service manual.
Defective Alternator Diode: An alternator recharges the battery and powers certain electrical systems. If your alternator has a bad diode, your battery can drain. The bad diode can cause the circuit to charge even when the engine is shut off, and the car won’t start in the morning.
Too Many Short Drives: If you are always taking short drives, this may be the causing your battery life to end too soon. If you keep on starting and stopping your car before your alternator has time to recharge, this would account for the reason why your car battery keeps dying and isn’t last as long as it should.
Faulty Charging System: The battery is charged by an alternator(driven by a belt from the engine). If there is something wrong with the system, your car battery could be dying too soon.
Extreme Hot Temperatures: Hot weather can drain the life out of your car’s battery. Build-up of lead sulfate crystals can occur when leaving your vehicle in high temperature for too long.The sulfate build-up can shorten the life of your battery and increase the amount of time it needs to be recharged.
Vibration: Vibrations from rough travel or a poorly-secured battery can shake loose or damage the plates.
The charging system is to maintain the charge in the battery, and to provide the main source of electrical energy while the engine is running.
If the charging system stopped working, the battery’s charge would soon be depleted. If the battery is weak and the alternator is not working, the engine may not have enough electrical current to fire the spark plugs, so the engine will stop running.
The main component in the charging system is the ALTERNATOR.
The alternator is driven by a belt that is powered by the rotation of the engine. This belt goes around a pulley connected to the front of the engine’s crankshaft and is usually responsible for driving a number of other components including the water pump, power steering pump and air conditioning compressor.
Connect the meter leads to the battery terminals and look for 13.5 to 14 volts (engine running, lights and accessories off). That means the alternator is charging the battery. While lights and accessories are turned on will be 13 to 13.9 volts.