Naples, Italy: Edizione Lucio Amelio, 1985
8 x 11 x 6 cm.
Edition of 200 [+ a few a.p] signed and numbered copies
One of Beuys' final multiples, the Capri Battery (or Capri-Batteri) was conceived on the island of Capri in Italy, while the artist was staying at the villa of his dealer Lucio Amelio. It consists of a yellow light bulb, a plug socket and lemon, housed in a wooden box with a signed certificate. On the side of the box, the following instructions are printed: ‘After 1000 hours, change the battery.’
Much is made of the work's ecological stance and the healing power of warm yellow light, but I'm inclined to believe Beuys' interest was primarily formal. The work is also regularly described as functional, though I've never seen it illuminated. Those are fresh lemons above and not even a dim light is visible. While the acid in lemons is able to produce a mild current, it's doubtful that it could function simply by inserting a standard plug. Additionally, the single milliamp a lemon might produce would be insufficient to illuminate the bulb.
I've also read, in countless listings, that the bulb has been painted yellow. The top photograph (in which the bulb's logo and consumer information is visible) indicates that this is false.
One of the two-hundred copies of Capri Battery recently sold at auction (Phillips, June 2015) for 17,222€.
Update: Apparently several lemons would not be enough: though the voltage might be high enough (1.5 volts with two lemons), the current would be too weak. Roman Keller, in Zurich, went to considerable lengths to make the piece function. See here for details.