Choosing a New Battery for Your Car

Has the battery in your car failed, or are you wanting to replace your current battery before winter temperatures take their toll? There are a few things you should know before buying a replacement.

Why do batteries fail?

Normally, sulfur crystals build up inside the battery when discharging, and break apart when charging. However, if the battery isn’t fully recharged regularly, those crystals have a chance to permanently bond to the lead plates, reducing current until the battery doesn’t hold enough power to start the engine. Electrolyte evaporation caused by high temperatures and stress from low temperatures can increase crystal formation. Because of the range of driving conditions a car can experience, battery life can vary widely from less than a year to five or six years.

What do I need to consider when buying a battery?

Size – The new battery should be the same dimensions as the old battery to ensure that it fits properly in the battery tray.Terminal Location – Most cars use top terminal batteries, connecting to the battery via C-clamps that attach to posts on the upper casing. However, many GM-build cars use side terminal batteries, using bolts to press connectors against terminals flush-mounted into the side of the battery casing. Many batteries will have both types of connectors.Voltage – Modern cars use 12 volt batteries, but many cars built up into the 1960s use 6 volt electrical systems.Cranking Amps (CA) – This is a measurement of power instantly available from the battery. The starter will require a minimum CA to turn the motor; this should be stated in the car’s owner’s manual. More is always better.

Cold Cranking Amps (CCA) – This is the number of amps available at 32 degrees F (0 degrees C.) The higher this number is, the better the battery will perform in cold weather.

Amp Hours – This is the total amount of power available inside the battery when fully charged. The more amp hours available, the longer the battery can run the car when the engine is off.

Manufacturing date – The battery should be less than six months old to ensure maximum life.

Maintenance – Standard batteries will gradually off-gas electrolyte, requiring the cells to be topped up every few months. “Maintenance free” gel batteries hold the electrolyte in a silica gel so it can’t boil off. Absorbed Glass Mat (AGM) batteries are also maintenance free and are very vibration resistant, making them a good choice for off-roading.

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