As I said, I installed a 50 watt solar unit and wish it had been 75 or 100.
In adition to the applications you mentioned (i.e., charging a laptop
battery, camera battery, etc.), I also run a ham radio transceiver (100
watts transmitter power) and a 12 v cooler.  My 50 watt panel does not keep
up with all this, so I have to ration the electricity very carefully.

Keep in mind that the rated output power is the maximum power that the panel
can deliver.  In the real world, reduced winter sunlight and the inability
to keep the panel always oriented perpendicular to the sun's rays will
substantially reduce the output.  Even on the brightest midsummer days, I
have not seen my 50 watt panel deliver more than around 40 watts.

Dave in KC
85 Westy