If your car's engine won't turn over and start, or turns over really slowly, it's probably because the battery is weak or dead. If the cause of the powerless battery is that you just forgot to turn off the headlights, it's plainly a matter of hooking up a battery charger to recharge your dead battery. It's more problematic if there's no obvious cause for the battery being dead.
Oftentimes, the cause for a flat battery with no apparent reason is either the battery is faulty or that it's not being re-charged by the alternator. It could be that the alternator is to blame, or perhaps that the belt driving the alternator is slipping. The next step in diagnosing a car battery problem to find out what's causing the problem.
An easy means of checking if the alternator is charging your battery is by starting the engine and turning on the headlights [This test works better if it's a least a little dark outside]. With the engine idling at normal speed, watch the spot where the headlights are shining. When the alternator is charging the battery, the lights will get a little bit brighter when increasing the revs. If the light brightness doesn't change, it's likely that the alternator is not really charging the battery or not charging it enough.
Another cause for the battery going dead is that it's just reached the end of its useful life. By making use of a battery tender device you can pro-long your batteries life. Batteries typically last for approximately 3 to 5 years, depending on their cycle of charging and discharging, and also on how well their maintained. making a lot of short trips, the battery will spend the majority of its time at less than fully charged, and this can really effect the battery life span.
Utilizing a Multimeter with its setting on voltage measuring it's quite simple to test the battery's voltage output. Connect the[+] red-colored multimeter cable to the positive terminal of the battery and then connect the [-]black test lead to the negative terminal. With the engine turned off, the voltage reading is typically around 12.5-12.8 volts. After starting the engine, and running at idle speed the voltage should read around 13.6-14.3 volts. If the voltage doesn't increase, it could signify your alternator is not charging the battery.
Starting problems can also take place as a result of loose battery terminal connections. Make certain that the connectors are tightly attached to the battery's terminals. Why not invest in a Battery Maintainer to help prevent your battery from not being fully charged. Another cause for starting issues is corrosion between the battery connectors and the battery poles. If corroded, they'll have to be removed and cleaned [Be sure the engine is turned off before disconnecting the battery connections].