How to Charge the Battery on a 2000 BMW 540I

1. Open the trunk of your BMW. If you pop the hood, you're looking in the wrong place. The battery is located in the trunk, on the passenger side. Open the trim panel and pull down. This will give you access to the battery compartment.
2. Remove the red plastic cover from your battery's positive terminal.
3. Clean the terminals and posts of your battery using a post and terminal cleaning tool. If the terminals are corroded or dirty, it will contribute to the draining of your battery. Also, dirty terminals will make charging more difficult.
4. Ensure that your battery charger is turned off and unplugged. If your charger has settings for batteries of various voltage, make sure it is set to 12 volts. Also, some chargers give you the option of setting the amperage at which it charges. The higher amps, the less time it should take to charge your battery.
5. Hook the positive clamp of your charger to the positive terminal of your BMW's battery.
6. Hook the negative clamp of your battery charger to the battery's negative terminal.
7. Plug your battery charger into an outlet. If the cord won't reach, you may need to use an extension cord.
8. Turn your charger on and wait. Depending on how severely the battery is drained and the amps at which you're charging, it could take anywhere from one-half hour to several hours for the battery to completely charge. If you have a maintenance-free battery recommended by BMW, you should see indicators on the top of the battery. When you see the indicator turn green, the battery is completely charged. If the indicator is black, it requires more charging.
9. Unplug the charger when the battery is finished charging and unhook the clamps. Replace the guards and trim panel, then start your BMW.