To figure out how many solar panels your small cabin will need you would take the wattage of the solar panel you're gonna purchase and then Divide #1 by #2.
For example if you're gonna have a 5 KW solar system then you'll need to have 20 solar panels that are 250 watts each.
Each solar panel will be about 1.6m x 1m in size so you'll need at least 32m² of roof space to accommodate the solar panels.
Or you could build an on ground platform to put the solar panels on if you don't have enough space on your roof for the solar panels.