Before anyone suggests a dynamo, i have two, and can indeed charge a phone from them, but this is different.
Planning a long day ride so i want to carry an extra battery to top up my phone if i need to. But, as i plan on starting pre-dawn and maybe spinning back on the road in the dark I'll have my solarstorm lights with me, but don't expect to use the full battery capacity.
So i don't need i carry two batteries, is there an easy way of charging my phone from the light battery? Is there an off the shelf product that converts from (i think) 7.2v to 5v usb?
If you're going to carry something extra to charge your phone (if there's something available) why not just carry a small external battery?
Or a solar charger that you can strap somewhere to get sunshine like the back of a pack? : https://www.amazon.co.uk/Innoo-Tech-Waterproof-Dust-Proof-Shock-Resistant/dp/B01AJTTELC/ref=sr_1_20?s=telephone&ie=UTF8&qid=1491895791&sr=1-20
or this
Available on uk ebay if you need it quicker
I have one of those Solarstorm packs, you'll need 4x18650 batteries and a charger (nitecore are good).
that solar powered one stevied is class. Pretty cool the things available now and just 13 quids!!
why not just carry a small external battery?
I have an Anker one which is superb, but I figure I shouldn't need to carry two 4-cell batteries.
Rudyard's link is pretty much what I'm after, thanks!