Changing a car battery seems like a simple enough do-it-yourself job for the mechanically inclined person. In many cases, this may be true. However, there is a proper and safe way to do it and a callous way of doing it. While many people have been lucky enough to have successfully installed a car battery--correctly or incorrectly--the fact remains that it's a volatile automotive component which has the potential to have deadly effects if mishandled.
Location and Owners Manual
The first step in changing a car battery is to find it. While this may seem like a simple enough task, keep in mind that several models of automobiles do not always place them in the engine compartment. Some vehicles may locate the battery in the trunk, under the passenger seat or even in a wheel well--which would require the removal of a tire. And some newer vehicles that still place them in the engine compartment may require the removal of other components to access the battery. Reading the owners manual for your vehicle will educate you on the location of the battery and perhaps even detail the task at hand.
Some vehicles may strongly recommend that the dealership only replace the battery. This might be to reserve equipment that has computerized codes, such as a radio or memory devices. In some applications, plugging in a memory saver will suffice, but understanding the vehicle prior to replacing the battery will be a valuable asset.
Safe Handling of a Car Battery
Car batteries contain a solution of diluted sulfuric acid that cover lead plates. This creates a chemical reaction when demand of the battery is called upon. The reaction emits a mixture of hydrogen and oxygen through vents of the battery. The combination of hydrogen and oxygen is extremely flammable and under the right conditions has the potential to ignite by an errant spark made by the battery connections. Safety glasses that surround your eyes and latex gloves should always be worn when replacing a car battery.
Removing the negative battery terminal should always be performed first when changing a car battery. This step will help lessen the chance of sparks occurring to the battery. Next, the positive battery terminal should be removed. Working in a well ventilated environment is also highly recommended. Isolate the battery terminals so they do not accidentally recontact the battery posts. Locate the battery hold-down device, and then remove that in order to remove the old battery from the vehicle.
Once the battery is removed, inspect the condition of the battery tray. If corrosion or debris is present, cleaning it off with warm water to prevent corrosion from reoccurring on the new battery is highly recommended. Clean the battery terminals as well using a battery terminal cleaning tool or spray. This will help to make sure the contact to the new battery is optimized.
After the new battery is installed onto the tray, replace the positive terminal to the battery first and then the negative. Again, this is to minimize sparks from occurring. Replace the battery hold-down lastly; this ensures that the battery is not loose in its cavity in the unfortunate event of a collision. A loose battery can become a dangerous projectile during an accident. Spraying the terminal leads with a battery terminal protector will help prohibit the formation of oxidized corrosive buildup on the terminals and optimize the battery's function.