This effective but counter-intuitive hack hinges on replacing the LED in your standard solar-powered garden light with two LEDs in order to extend the battery life.
When two LEDs are wired in a circuit they draw less total power but the output of the two slightly dimmed LEDs is virtually indistinguishable a single one. Tests at the project blog BigClive yielded a run time extension of roughly 25%. Hit up the link below to see just how easy it is to crack open a cheap solar light and upgrade the LEDs.
Hack Your Solar Garden Lights [via Hack A Day]