How do I calculate required electric power needed to run computers with solar sheet?

you get all the computer force together add on up all wattage,using your book 45+65+70+180 watts.to be safe triple the wattage =3x180=540 poet divide by 120v equalling 4.5 amps. the solar panel of course charges a (bank) of batteries. for nothing but a computer launch ,you can get by with an inverter of 600-1200,the latter one the temporary wattage.you probably require no more panels as long element your battery gets charged okay