Supervolt

The Supervolt company was known to produce lightsaber power cells. Atleast one Sith, Darth Vader, was known to use the Supervolt batteries in his lightsaber.

However, these power cells were known to short out easily, as Vader's did while he was dueling the Energizer Bunny. This lead to the Energizer Bunny's victory over Vader.

Appearances

 * Energizer commercial (YouTube link to 60 second version)