Learn to calculate how much electrical energy your solar panel must generate to run your home’s solar power system.
In this article:
Solar Power | Measuring the Power Solar Cells Produce
This article is the second in a three-part series on off-grid survival using solar power systems. In the first installment, I talked about how solar power works and the types of solar panels available.
In this article, I’ll share with you how to calculate the amount power from solar energy you’ll need to support your home or boat. For the third and final post, I’ll share how to mount and wire your new panels.
How Much Power Do Solar Cells Make?
Generally, we measure solar panels by wattage and that is how we buy them.
You can buy solar panels for boats as small as 10 watts to as large as 200 watts or even larger. But it is easier to understand when we convert watts to amperage.
We arrive at these values by multiplying the number of hours the panel spends in full sun (usually defined as 8 per day in Florida) times the panel’s wattage.
For a 195-watt solar panel, the output would be 195 x 8 hrs = 1,560 watts/day. Taking it a step further, 1,560 watts/12 volts = 130 amps per day.
Keep in mind that solar panels produce DC power which means that you will need a deep cycle battery bank to hold the charge. Batteries are rated by the amp hours they hold.
So What Is Needed in a Solar Panel Setup?
Obviously, one or more solar panels are necessary to make the system work. In addition, you will need:
- a large bank of deep cycle batteries, the bigger the bank the better
- an inverter, choose between pure sin or modified (to be discussed in another article)
- a controller
- proper wiring and fuses to wire the parts together.
Energy Consumption – A
My guiding principle on how many panels to buy is simple. Buy as many panels as your budget and mounting location will allow. You cannot have too many, but you should complete an energy audit to make sure you are buying enough for your needs.
Example, if you have 3 interior lights that draw 2 amps each and you leave them on for 24 hours per day, your consumption would be 3 x 2 x 4 = 24 AH/Day.
You can generally find the amp load for appliances on a label inside a door etc.
Read the full article on calculating your solar panel setup here on
You should now have an overview of how to set up your solar panels at home. Next thing to do is decide whether you need something big to prepare for unforeseen disasters, or simply work with what limited budget you have for the time being.
Do you find the article helpful in your plans for installing a DIY solar power? Share your thoughts with us in the comments section below!
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Editor’s Note: This post was originally published on December 10, 2015, and has been updated for quality and relevancy.