I know that this topic is not really related with the Warm Showers community but I am kind of desperate regarding this. So I will do a cycling trip with solo camping all the way and I am failing to find reliable sources about dynamo usb charging. I just want to charge my Galaxy s7 during the tour and I do not know what charger would do the job. If anyone here got some experience with this I would appreciate some advise. Is it works or not?