This is currently an unexplored idea for me, but I would like to know some ways of logging voltage and/or current over a 24 hour time refrence. While I will begin with my solar power experiment, I can think of at least 100 other projects to quickly put that capability to use. Being able to link to an old Android (Froyo) smartphone also sounds like it could prove useful. What would be some options to investigate, so that I don't spend countless hours hunting the wrong patern?
Solar power experiment: http://forum.allaboutcircuits.com/threads/how-to-figure-solar-capacity-as-added.113230/#post-879167
Solar power experiment: http://forum.allaboutcircuits.com/threads/how-to-figure-solar-capacity-as-added.113230/#post-879167