Once you are familiar with the basics of your battery charger, you can now connect it to the vehicle’s battery. You can charge the battery while it is still inside the car or if it has been removed, either method is fine. First attach the positive (red) clamp to the positive post on the battery. The positive post will have a “+” indicator on it. Next attach the negative (black) clamp to the negative post on the battery. The negative post will have a “-“ indicator on it.