Car Battery Tester

Before you do anything with a car battery, please consider the following safety precaution:

You need to wear eye protection
Car Batteries produce hydrogen gas that is extremely flammable. So you should remove any naked flame or avoid any action that can cause spark. This includes cigarettes and other smoking products.
Car Batteries contain sulfuric acid so its recommend that you wear latex gloves to keep battery acid from burning your hands.

During cold season, your car batter will have a hard time cranking your engine. This situation attributes to a lot of technical details but we are here interested in avoiding some inconvenience that can be caused due to dead battery in cold season.

I hope you send your car to mechanic for routine maintenance in the quoted running hours in the car's manual. If not, you really need to start to doing this routine checks. It's a good practice because it will avoid any surprises and save you time and money. Most of your car's moving parts are exposed to wear and tear and they have a factory set running hour for checkup and renewal. These running hours are way less than the failure limits, so you are safe. You can even give yourself some more time to visit your mechanic, but don't take this chance, do it on time, if you have the time. The same routine checks and maintenance applies to car batteries. But when it comes to car batteries, there is additional weather condition that you need to take into consideration while keeping the usual routine checks. You need to test your car battery just before the winter season and make sure that it's in good shape. If not renew it and avoid any surprise that can cost you more money.

So what is a car battery tester and how to use it?

Car battery tester a small multi-meter like device, which includes a heating-coil and voltmeter. Car battery tester's voltmeter is used for checking battery open circuit voltage. It also has a switch that turns on a very low-resistance dummy load. You use that to test how much short-circuit current the battery can put out. A fully charged "12 volt" lead-acid battery is about 12.6 volts.

Electricity is stored in the battery and then supplied to the vehicle when the engine is not running. While the engine is running the vehicles alternator charges the battery for future use. (Note: never disconnect the battery while the engine is running. If the battery cable is disconnected from the battery a spark can be generated which can cause the battery to explode or a major electrical malfunction to occur.)

To check a battery surface voltage, first you need to remove the positive terminal protective cover of your car battery. It has a red color. Then connect the +positive terminal of your car battery tester (which also has a red lead) to the positive side of your car battery terminal. Connect the - negative (black) side the car battery tester lead to the negative battery terminal. With the car engine turned off and the car sitting over night the battery voltage should be between 12.5 and 12.8 volts. Anything lower is a sign off weak battery, so you need to change it to be safe in cold season.

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