Today was very cloudy all day and they were the kind of clouds where you could barely tell where the sun was in the sky, and yet I managed to go from a 76 percent charge on the batteries this morning to a 99 percent before the sun went down. I'm always amazed how well the solar panels work even on some of the worst days.
Using 24 percent of my battery bank is a bit more than I normally use. On average I'm using about 20 percent every night largely depending upon how much I use my laptop. As I've mentioned before my 17 inch Asus G 75 uses anywhere from 8 to 12 amps an hour depending on what it's doing and last night I watched a couple of movies on DVDs and stayed up past 10 o'clock so I used more amps than I normally would.
The Arctic Fox has about half an amp of phantom loads and one or two amps of things that I could turn off but don't bother to inless I've had several days of cloudy weather. The TV stays plugged in which uses a little bit, the refrigerator's control board uses some, the cell phone booster and the Wi-Fi antenna use about an amp each. the inverter used about an amp just idling, of course its not using anything at the moment because it's sitting on the floor beside my chair.
So all in all I use three or four amps when nothings going on, but I could save most of that if I wanted to turn some things off that I don't actually need running.
One thing that I have realized is that when it comes to figuring out a solar system and how many amps of electricity you're going to use in a 24-hour period its not all that hard. What's hard is determining what its going to take to the replace the amps that you've used.
For instance it's easy to add up all of your stuff and get a number for watts or amps, I've always preferred amps because it's a smaller number and therefore less scary. But determining how many batteries its going to take to supply those amps and how many solar panels it will take to charge them comes mostly from trial and error based on your particular lifestyle.
If you're going to spend a lot of time in South Florida where it clouds up and rains a lot your solar system will be different than someone who spends a lot of time in the Southwest where it's usually sunny and cloud free. It took a lot longer to charge up my batteries last winter in Texas than it did the winter before in southern Arizona.
I think the best way to find out what works best for you is to install a solar system and battery bank that you think will work, but install a bigger solar controller than you think you will need, and heavier wires than you think you need, that way you can easily add more batteries or solar panels later, and if you find out you guessed right and don't need anymore solar, you're still better off with bigger wires and a better solar controller