Originally Posted by Junster
Hobby Shops sell sub-c ni-cad batteries for r/c cars. They are just the right size to make a end to end straight battery pack that will slip inside your seat tube. Slip the cells in a fat piece of shrink tubing after you wire it and tie something to it to pull it out if you need to. The draw from bike lights makes the pack very long lasting. If you have a frame with a fatter seat tube you can also rob cells from a old rechargeable drill pack and make one that fits inside the seat post itself.
Seat post battery storage! Thats a sweet Idea. Had not thought of that yet. Thats what I love about this forum! Will have to pack them in well for rattle sounds do able though.