Nikon has released version 1.11 of the firmware for the D80. The firmware update resolves an issue with the battery indicator: in certain circumstances, the battery indicator light blinks regardless of the actual battery charge. If you did not update to version 1.10, that firmware update is included in the new version.
You can download the update from the following pages if you are in the U.S:
If you are located in the E.U, updates are available on the following pages: