Hi, I posted something related to this is in a thread about sleeping bags yesterday, copied and pasted below, BC!
'Another tip, instead of worrying about finding a charging point for your phone and even worse, worrying about if it'll get nicked while on charge get a 'solar power bank' (search on eBay or Amazon), start at around £7 on eBay and go up to £15 or £20 on Amazon. A few naysayers claim they don't work, either they have older type ones or they bought the £7 ones off eBay. After a bit of research I got one particular one off Amazon for £20 (I almost got a £13 from Hong Kong off eBay) . You hang it off your rucksack, it charges throughout the day, if it's sunny it'll charge in a day, if it's raining (I got a waterproof one) it'll take up to 4 days but when full you'll be able to fully charge a decent smartphone 3 times with it. They also double up as a torch/lantern and weigh around the same as a large smartphone, I don't mind the extra weight but you might
I can send details of the models I looked at if you're interested in one.'