To do this, I use 3 solar lights meant for the garden. These charge a 1.2V battery in 6 to 8 hours and then produce light for at least 8 hours. The top part of these things (namely the solar cells) ended up on the rooftop of my garage...

...and I mounted the bottom part (battery and LED light) on the garage ceiling. Using 3 cables I connected them, using the rain pipe as a channel.

H. van Rein, Assen, The Netherlands