1. The very first thing you should do when you want to disconnect your car battery is to turn off your ignition. If your car is automatic, set it to parking, but if it is manual, put it on the first gear. Put on a glove for your safety.
2. Open the hood: Press the button or pull the lever to open the hood after you have turned off your ignition. This button or lever is usually located somewhere around the steering wheel. Well, it all depends on your car. Make sure you understand your vehicle with the help of its manual.
3. Remove the negative terminal: After you must have opened the hood and/or located the battery, look for the terminal that has the minus (-) sign written on it. The terminal is usually covered with black cover. It is safe to remove the negative terminal first.
4. You will need your spanners and probably plier to loosen the iron used to tighten the terminal.
5. Remove the positive terminal the same way you removed the negative terminal.
6. Now it is safe to lift your battery from its tray.