Short simple general information;
A "watt" is a unit of power it is equal to voltage x Current
Solar panels supply DC (direct current)
Batteries will supply DC power.
Most solar charging systems are going to store power to a battery or batteries.
You need a "solar charge controller" to keep from over charging your battery.
Anything you plug into a wall plug-in is going to be AC (alternating current)
Here in the USA your going to figure about 110-115 VAC out of your wall plug.
To convert your DC from the battery storage to AC you need an inverter.
You see small ones that plug into your cigarette lighter and let you run small house hold items while camping or such.
Your box fan that plugs into the wall is going to be AC.
So if your fan uses 77 watts on medium and runs on 115 VAC it draws about .6 amps (.669)
Watts is the energy that is needed to make something work, so it does not change.
But the other two can.
So to run your fan you would need about a 100 watt inverter or larger.
So to run your AC fan you would need an inverter, or you could buy a fan that runs on DC.
There is LOTS more to it, but that is a simple overview.
BTW: I have seen a couple of fans with built in solar panels on Amazon. Most are made to clip on your sun visor in your car. But I have yet to see one with good reviews...
