Open the trunk and lift up on the small, black-looped handle to pull up the luggage compartment carpet and floor.
Locate the battery compartment. The battery compartment is located near the right rear wheel.
Turn the lock nuts 1/4 turn to loosen and remove them. Then, pull up on the battery cover.
Loosen the retaining nuts on the battery brace and pull the brace off the top of the battery.
Loosen the retaining nut on the negative battery cable clamp and slide the negative battery cable clamp off the battery terminal.
Loosen the positive battery terminal cable clamp retaining nut with a socket wrench and slide the positive cable clamp off the battery terminal.
Lift the old battery out of the battery compartment and lower the new battery in.
Reconnect the battery cable clamps. Connect the positive clamp first, then connect the negative clamp last. You must connect the negative battery clamp last to avoid a sudden shock or arcing of the power terminal.
Put the battery cover back and secure it with the lock nuts, and then lower the luggage compartment floor and carpet.The battery in your BMW M5 is not located under the hood of your car. Unlike most automobiles, the battery in the BMW M5 is located in the trunk. The battery should be checked ever year, preferably before winter, to make sure that the battery is charging normally. Replacement batteries for your M5 can be purchased from any auto parts store. When accessing the battery, it is important that you avoid touching the battery terminals accidentally with the socket wrench you'll be using. Since you will be accessing a tight space in the trunk, it's easy to cause the battery to arc with the socket wrench handle. However, this can destroy the battery and possibly cause an explosion.