I have one solar related question, but please bare in mind that I am a complete newbie in this field so if my questions are stupid, I apologize.
I want to use a solar panel with this USB controller/charger for smartphone/tablet charging:
I found a lot of different solar panels that match my needs (primarily, by their dimensions) but when it comes to watts, I dont know what to select (or better yet, I dont know what is enough). So, if it is possible, can you tell me how many watts is enough to charge today's smartphones or tablets?