(A small Disclaimer) I pretty much threw this little guy together in about a day and kinda forgot to take pictures of what it looked like during construction. So for that I apologize!
Essentially it is a USB Battery/Solar Power Charger that switches between two battery banks to provide power to a USB MintyBoost Charger. The reason for having two separate banks is that i wanted to be able to charge my phone while also utilizing the wonderful sun to charge the battery bank. So I quickly decided that the simplest solution would be to use a DPDT switch to swap between battery banks and then using two SPST switch to allow solar panel power to flow to whichever battery bank was not currently being discharged.
- Electrical Wire (Copious Amounts)
-Altoids Tins (2)
-DPDT Switch (1) https://www.sparkfun.com/products/11139
-SPST Switch (2) https://www.sparkfun.com/products/10727
-Rechargable AA Battery (5) https://www.sparkfun.com/products/335
-MintyBoost Kit (1) https://www.sparkfun.com/products/10094
-Solar Panels 0.5W (2) http://www.radioshack.com/product/index.jsp?productId=12609999
-AA Battery Holder (Any kind will do, long as you have 2 holders that hold between 2 or 3 AA's)
-Packing Foam to Pad the Mintyboost and other Components
-Paint For Making it look pretty!
So in a nutshell what we have here is two Altoids Tins Hot glued together with on each "door" there is a Solar Panel. I used a dremel tool to make a opening in between the two tins, as well as a opening for the mintyboost and sockets for the switches. one Tin we have the Switches and a 2 AA battery holder and on the other Tin we have the MintyBoost and a 3 AA holder. As Shown By my crude Schematic the battery banks are separately energized by the panels with the two SPST switches and the DPDT switch swaps between banks. Its important not to plug a device in while charging the batteries as the combined voltage from the two power sources could damage the mintyboost since it was designed to step up voltage not step down.
I hope this was helpful in any way, if you have any questions feel free to ask, as i know i sorta just winged it. Thanks!