I'll be spending a lot of time out of town this summer, and I can't give up my music. Is there any decent solar chargers out there? I need something to charge a Cowon s9 and also my mobile phone. So something with a USB port and around 4000-5000mah? Something that will charge in 8 hours or so. I would prefer it to be very portable too. Anyone had experience with a product that fits these categories?