How Do You Put Batteries In Apple Wireless Keyboard. Magic Mouse is unavailable for use while charging. You should have a Working Keyboard.
Replace the battery compartment cover. Apple Wireless Keyboard requires the passcode that appears on your Mac. Slide the two three on the previous generation replacement AA batteries into the battery compartment.
I found the solution on the apple forum.
Answer 1 of 2. Using the screwdriver with one or two forceful pushes push hard and the slip ring will give way the battery will move up towards the opening over were the plastic bag is at. Make sure the positive ends are pointing the correct direction. I do use the keyboard quite a bit probably 8 hours a day but I remember when I used this keyboard in the past the batteries lasted for many months not the few days they are lasting now.

