A solar generator can be used every day, but its duration of use depends on its battery size, power output, solar recharging speed, and what you're powering with it.
We will also calculate how many kWh per year do solar panels generate and how much does that save you on electricity. Example: 300W solar panels in San Francisco, California, get an average of 5.4 peak sun hours per day. That means it will produce 0.3kW × 5.4h/day × 0.75 = 1.215 kWh per day. That's about 444 kWh per year.
That's approximately 29kWh per day, or 1.24 kWh per hour — which is a lot. In fact, the U.S. is the second-largest consumer of electric energy globally, losing only to China. With that said, for a solar generator to power an average U.S. household for, let's say, six hours, it would need to provide 7,44kWh.
A 6kW solar system will produce anywhere from 18 to 27 kWh per day (at 4-6 peak sun hours locations). A 8kW solar system will produce anywhere from 24 to 36 kWh per day (at 4-6 peak sun hours locations). A big 20kW solar system will produce anywhere from 60 to 90 kWh per day (at 4-6 peak sun hours locations).
A 100-watt solar panel installed in a sunny location (5.79 peak sun hours per day) will produce 0.43 kWh per day. That's not all that much, right? However, if you have a 5kW solar system (comprised of 50 100-watt solar panels), the whole system will produce 21.71 kWh/day at this location.
To calculate solar panel output per day (in kWh), we need to check only 3 factors: Solar panel's maximum power rating. That's the wattage; we have 100W, 200W, 300W solar panels, and so on. How much solar energy do you get in your area? That is determined by average peak solar hours.
In California and Texas, where we have the most solar panels installed, we get 5.38 and 4.92 peak sun hours per day, respectively. Quick outtake from the calculator and chart: For 1 kWh per day, you would need about a 300-watt solar panel. For 10kW per day, you would need about a 3kW solar system.