Though it may appear to be one of those things that 'takes care of itself', checking your car battery on a regular basis is important part of your car care routine, along with checking the tire, the wipers, and all of the fluids. It is crucial that you check your car battery on a regular basis and perform routine maintenance regularly, as well, and as needed. If the battery manufacturer claims the battery is 'maintenance free' you should continue to make checking and maintaining the car battery as a part of your regular maintenance routine.
Checking your car battery will prevent you from being stranded somewhere with a car that will not turn on at all. The simplest thing you can do to maintain your battery is to simply just keep it clean. Basically, all you, the owner, will need to do is to wipe the battery clean of oil and dirt and dust. (It is recommended to make cleaning the battery case a routine part of your engine detailing.)For very oily or greasy battery cases, you can use a mild soap on a very damp rag to wash it away. Then use a dry cloth to dry the battery case well, as well as leave it with the shine and cleanliness of a new battery case. Check the battery case for any types of cracks, any kind of bulges and any other abnormal imperfections. These could be signs that the battery, itself, will need replaced. In the event of damage to posts or clamps or severe damage to the battery casing, you should bring your car to an expert mechanic at a local car repair shop for further inspection and repairs.
Now, to clean battery posts and or terminals; Remove and loosen the negative cable first. (Negative is always black or uses a minus (-) sign to recognize it). After you have removed the negative cable, remove the red cable (this is the positive cable). Combine a small mixture of baking soda and water until it becomes a paste form. Now using a small wire brush, use the paste on the battery posts, as a cleaning agent. This homemade paste will remove rust and corrosion and any oil or other substance that will have on the charging system of the battery itself. Be sure the paste is quite thick, and not too much water has been added. It should not drip at all. If any part of your battery or battery casing shows signs of serious damage, it may be necessary to bring your car to your local car repair shop to have them replaced or repaired to safe conditions.
Now that the battery posts and case are cleaned, maintained and inspected accurately, coat the clamps and the posts with a very light coat of oil or grease. This will aid in preventing rust and corrosion in the future. Now you can begin to reconnect the cables, connect the positive (red) cable first, then the negative (black). Taking care of your battery is critical in the cars performance and essential to the car care process.