Hi, I am planning a trip where I will be living out of a backpack for several months and need to be able to use my phone to keep in contact with family and friends and be able to use the gps and compass. So, basically what I need to know is... what is the best option for keeping my phone charged for extended periods of time? Are there any decent solar chargers?? I have read many reviews and it seems that most are just not practical for what I plan to do. Would I be better off just buying like 10 spare batteries? how about those power banks that run on AA's? something that is both small and lightweight is ideal.. I also can't spend a fortune on this as I have a lot of more important gear to buy still. Please help me out with this.. I will greatly appreciate any and all suggestions.