In reply to wykealpha:
For the UK or somewhere (usually) sunnier?
I've got an Anker 21w 3-panel, but the battery is the key bit. The trick is to start with the battery fully charged, charge your phone and cameras at night, then top-up the battery by trickle charge via the panel during the day. A lot of devices don't like intermittent power and will stop charging if the sun goes in and out a few times.
I've got an Anker 20100mha USB-A and Aukey 10050 USB-C powerbank batteries. For two/three day trips the small battery is fine on its own. For longer I take the bigger one and the panel. In the tropics it works great - a week or more and you can return with everything fully charged - Powerbank, Sony DSLR, iphone, Petzl Nao. The powerbanks have two outputs so you can charge two items at once. You can't put power in and out at the same time though.
In the UK you're more dependent on the weather and fettling the panel to keep it perpendicular to the sun. Bear in mind a 20100mha powerbank will take 9+ hours to full charge from a socket, so you do want to be starting charged and topping up.
Getting a decent setup was motivated by a trip to Orkney a few years back - in June and decent weather - where we had a couple of small charging panels which were hopeless.
Options for DSLRs/ laptops etc which require higher power than USB are limited, pricey, bulky and heavy - not an option for backpacking. This is one of the reasons I switched to Sony cameras.
Good detailed review here: https://diglloyd.com/articles/power/Anker-PowerPortSolarLite.html
Post edited at 09:43