You get in your car in the morning, insert the ignition key and turn it. But all you get is a click. Or maybe you do not get anything. Well, do not panic. You can solve the problem by following a few easy steps:
1. Check to see if you left lights or any other electrical device on all night. That will run your battery voltage to zero in just a few hours. If that is the case, a jump-start will get you going again.
2. If you did not leave lights on the previous evening, look at the terminals on the battery. They should be clean and tight. If they are not, corroded, loose terminal connections may be your problem. You can clean them with a special terminal cleaning brush ($ 3 or $ 4 at an auto-parts store). Then reattach them. Do not put a baking soda and water solution on the terminals or on any other part of the battery.
3. While at the auto-parts store (or any hardware or tool store), pick up a direct-current voltmeter for about $ 5. Also, get a 12V test light for about $ 3 (It has a pointed probe, a red light and an alligator clip on a wire). Press the positive (red) and negative (black) probes of the voltmeter to the corresponding battery terminals. At rest, a good battery will read 12.0 to 12.5 volts. If you have a lesser reading, either attach a battery charger or remove the battery and take it to a shop for recharging to bring the voltage back up.
4. A good shop (and most auto-parts stores) will charge your battery plus conduct a load test with a special meter. That will tell them if the battery has a shortened cell or some other problem.That is, the battery may charge up to 12.0 volts, but the moment a load is placed on it, the voltage indicator will drop precipitously. That means you have a bad battery. Replace it and your problem is solved.
5. When reinstalling a new or fully-charged "good" battery in the car you should check for unwanted drains on the electrical system. Connect the positive battery cable, but leave the negative cable disconnected. Then connect your 12V test light to the negative cable and put the pointed probe on the negative battery terminal. If the light goes on, you have an unwanted power drain somewhere on the car (lights, radio, etc.) You may have to temporarily disconnect the under-hood light to avoid getting a false reading. If the light on the 12V test light does not go on, you can be assured you do not have an unwanted drain.
6. Finally, after the new (or good recharged) battery is installed, start the engine and again check the voltage at the positive and negative terminals on the battery. The reading should be 13.0 to 13.5 volts. If it is less than that, the alternator will not properly charge the battery. If it is higher than 13.5 volts you will soon encounter an overcharge condition that will destroy the battery. Note: A reading of less than 12.5 volts when the engine is running usually indicates a faulty alternator (which must then be replaced).
7. Do not whine about the money you spent on small tools and test meters. They will come in handy on other occasions.