Joined: Aug 2010
Posts: 12,729
Likes: 2,106
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
Looks like the panel output is slightly higher than the USB standard of 5V 1A. But as long as the USB port on the panel does not go over voltage, should not be a problem. Once the battery is full, it should stop taking more power from the panel. Due to the higher rating, I would not directly connect an expensive smartphone to it, but I often needlessly get overly cautious about that sort of thing.
I recently bought two panels at 2.4 watts each that I plan to use to charge similar batteries.