Off grid solar power provides power at night when there is not sun and uses the sun during the day to charge a battery bank. The battery bank is what the device runs on at night, or when the power is needed. As long as power isn’t needed 24/7, off grid solar power is a great and viable choice.
There are ways to do 24/7 power with off grid solar; however, the battery bank and solar needs to be much larger. Since you only want to take your battery system down 20 per cent per day / use to ensure the batteries last, the solar and battery backup needs to be large enough to handle the load for days. This also will allow your off grid solar system to work during times of bad weather.
Sizing the system is a pretty easy task. Take the total load required on an average day and multiply that by the number of days the system needs to operate; typically 5 days is long enough. Add for a little overage, say 20 percent or so for times with bad weather. Finally, find out the number of sun hours you have available in your area in the dead of winter (the shortest day of the year) and you will have the total number of amps you need to run the load for the 5 days.
Find out how many amps are provided by the solar and the amp size of the battery system. You need enough power generated by the solar panel and enough storage in the battery to make sure the system lasts. To find out more about how solar power is generated, check out this video from the DOE:
That’s about how simple off grids solar power is. Making sure you have enough power being generated and stored is the key to making the system last. You can cut corners by lowering the power or sizing for the summer sun hours, but then you will be sitting in the dark when the sun decides to hide behind a storm or in the middle of winter. Best bet; make sure you have sized your system properly to always have the sun shining on you.