Not all drained AA batteries are dead. Most, like our cell phone batteries, are just low, very low, on juice. The problem with most AA batteries is that they cannot be charged and thus creating waste problems. But designer Bor-Ru Huang, thought of a simple but effective way of extracting those precious juice using a clock. The Eco Clock, which won the Liteon Award, has 12 slots for 12 batteries that combines all their charges to run the clock. Its even got a led indicator to show which batteries are already too low. Designs like these will be very useful to end users by helping them save from purchasing new batteries for their clocks.
Source Yanko Designs