I have several of these lights. The button batteries don't last very long at all. I was wondering if anyone can give me some instructions on how to convert and what parts/battery pack I would need. The lights are pretty cheap, and the on off switch is really poorly made-- but they do work well when you find one that has a little bit of life in it. I imagine the battery pack is either triple a - double a. Please, if you can help, layman terms would be very much appreciated. Thank you in advance.