Some high power epoxy encapsulated solar panels (30 for £15) and the white LED driver ICs off Ebay to repair some solar patio rock lights. Quite a few extra to play about with as they're so cheap: Solar mobile charger might be handy.
Panels are roughly 2" square and deliver 2V at 150ma compared to the rubbish in the existing cheapo lamps that only deliver 30-40ma. Combine with 2500maHr AA cells (were 600) and upped LED current should turbo them.
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History is much like an endless waltz: The three beats of war, peace and revolution continue on forever.
However history will change with my coronation - Mariemaia Khushrenada