Which Is the First Step in Building a Solar System: Guide - ShopSolar.com
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Which Is the First Step in Building a Solar System?

Short on Time? Here’s The Article Summary

Building a solar system requires careful planning, beginning with determining the size based on your energy needs. Before purchasing equipment, use a solar calculator to estimate the system's size and capacity. Start by calculating the watt-hours per day for each appliance by multiplying its wattage by the hours used daily. Sum these values to get your total energy consumption. Next, use this information to size your battery bank, considering factors like the number of days without sunlight and the lowest temperature the batteries will face. The calculator will then provide the required amp hours and the number of batteries needed.

For solar panels, determine your area's average sunlight using solar maps. Enter the sun hours into a calculator, which will estimate the total wattage and number of panels required. The calculator will also suggest the appropriate solar charge controller. These calculations serve as a blueprint for your solar system, ensuring you select the right components for your energy needs, whether for a home, RV, boat, or shed.


Building a large or small solar system is a process consisting of many steps, so it’s important to know where to start.

So, before you run outside and buy a home solar panel kit, it’s important to read up on the steps to set everything up.

Here are what we consider to be the first steps in building a solar system.

Sizing the Solar System

the first step in building a solar system

Before we can start gathering the various components of a solar system, the first step is to find out the size of our solar system based on our needs.

It’s pointless going out and gathering all the equipment before knowing what exactly you want to power.

Think of building a house as an example. Builders don’t go straight into constructing the house without having some form of a blueprint.

They’re given a design from an architect that covers where they’re going to put everything and all the components they need to put everything together.

So, the first step starts with using a solar calculator to get an idea of the size and total capacity of your solar system.

These solar calculators require your electrical needs before performing any calculations. Once all the calculations are finished, you’ll have an idea of the recommended size of your solar system.

Determining Watt Hours Per Day

This is a matter of finding the total wattage of all your appliances and multiplying them by the number of hours you use them. 

This gives us the average watt hours that the appliance uses per day.

For example, let’s say you’re wanting to build an RV solar system and have the RV’s interior lights running at 20W for 3 hours per day. This gives us 60Wh per day for that appliance.

If the wattage isn’t found on the appliance label, you’ll find the voltage and amperage label. Simply multiply these two values you get the wattage.

Now that you know how to determine the average watt hours, you want to do this for every appliance you want your system to power.

Finally, add all the watt hours together and voila, you have the total watts per hour that you intend to use on your system.

which is the first step when building a solar system

Calculating Your Solar Needs

There are a variety of solar calculators online that help you figure out the size of your solar system. The key is to pick the one that makes the most sense to you.

What these calculators do is calculate the size of the individual components of your solar system.

Battery Bank Sizing

Most calculators start with battery bank sizing as it uses your watt hours per day as a variable in the equation.

Once you enter the watt-hours per day, it will ask you how many days you want your solar system to run without sun. This is to account for the cloudy and rainy days.

If you want a portable solar system for camping or regularly use your RV, this value will be lower since you’re always on the move and your location changes.

The next variable to consider for your batteries is the lowest temperature they’re going to be exposed to.

This requires you to enter the lowest temperature your area reaches to determine how the batteries will function at different temperatures.

The calculator does its magic, and it will return the number of amp hours needed for your battery bank as well as the recommended number of batteries.

which is the first step in building the solar system

You can also pick the voltage of the battery you’re wanting to include in your system and if the voltage is large, you’ll require fewer batteries in the bank.

Sizing the Solar Panel

Whether you’re adding solar panels to existing systems or this is your first solar system, sizing the solar panel always involves the same approach.

Looking at a solar map, you need to determine your area’s average sunlight.

There are a variety of solar maps online that give you a generalized idea of the different areas in the states and their respective sunlight hours.

These maps are color coded from orange to red, ranging from weak exposure to strong respectively.

Once you enter the sun hours, the calculator gives you the total wattage of solar panels as well as the recommended number of solar panels for an array.

You can enter the wattage of a solar panel and it calculates how many solar panels will be sufficient for the recommended wattage.

The calculator also determines the recommended solar charge controller using the calculations from the solar panels.

Once all the calculations have been completed, you’ll know the recommended size for each component in the solar system.

which is the first step when building solar system


If you know the size of your solar system, the steps that follow become a walk in the park.

This step acts as a blueprint for anyone wanting to build a solar system. 

Whether you want a solar system for boats, homes, RVs, or sheds, the first step is always to calculate the solar needs.

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