So a few times this summer I have needed to use my GPS on the cellphone. It becomes battery intensive with the turn by turn navigation.
I didn't want to hardware a 12v supply to my M50 and in my case, devices that I own are typically powered via USB. So I put together a solar powered USB charger. This gives me the ability to charge while riding but also to just throw it in the bags whenever I don't want to use it.
I went to Radio Shack and bought a solar cell (14.99). I had a old USB port from a computer so I yanked that out. Cut off the excess wires (white & green). Spliced red/red black/black. Soldered everything up. Put some heatshrink in the wiring to protect it and placed the housing back together.
I tested it out on the volt meter first and then I plugged in my Blackberry. It entered charging mode in a few seconds and I was done.
Anyways, I thought I'd share as it is a cheap solution and requires pretty much nothing. I'll be placing some magnetic tape on the backside so that when I use it I can just sit it on the tank. I also plan on making a quick disconnect for the unit and making the USB port a permanent part of either my speedo or the ABS tank cover.