Solar Panels and Battery Systems: How to Properly Size Your Setup

Are you thinking of shifting to solar for your household requirements? Do you want to reduce your hefty electricity bills by investing in Solar? But do you know which system will fulfil your energy needs?

While opting for the solar system is one of the cleverest decisions you can make today, it doesn’t make the shift easier. With so many solar companies in the market, choosing the right solar panel and battery package can become overwhelming.

That’s why we have prepared this guide to help homeowners and businesses. So you can choose the appropriate solar panel and battery size that fits your energy needs and goals.

Understanding your Energy Needs and Goals

Before sizing your solar panels and batteries, you first need to understand your energy consumption. You can do this by going through your annual and monthly electricity bills. It will give you a basic idea of how the power requirements change with seasons. 

Once you grasp it, it’s time to work on your energy goals for shifting to solar. Do you only want to reduce the hefty electricity bills, or are you planning on becoming completely energy-independent? Do you want to install more appliances for future needs? All these things will help you with your solar system sizing in the long run. So if you’re looking for cheap electricity rates in texas, this is certainly the way to go.

How to determine the appropriate size of solar panels?

1.   Calculate your energy usage

  • Collect your annual electricity bills.

Gather your annual electricity bills to understand your energy usage in Kilowatt-hours. It helps you to get a basic idea of when the usage spikes over the year.

  • Figure out your average monthly usage.

Determine your monthly power usage by adding all 12 months’ kWh usage and dividing the add up by 12. However, remember that solar panels produce more in summer due to high sun exposure.

  • Determine your daily power usage 

Similarly, divide the monthly power usage by 30 to get the daily kWh usage.

2.   Determine your Solar Peak hours

Your solar panel efficiency relies on the amount of sunlight it receives during the peak hours. The average solar peak hours vary with the climate and location.

Before installing a solar system, you should find the appropriate number of peak hours for your solar panel. You can do that by searching for the peak solar hours of your city.

3.   Calculate solar system size

Once you complete the above two steps, it’s time to calculate the solar system size. Take your daily kilowatt-hour usage and divide it by solar peak hours. It will give you kW output that you can divide by your solar panel’s efficiency. This way, you will get the number of solar modules that will fit your solar system.

You can use this formula for basic understanding:

(Daily kWh/average sun hours) x 1.15 efficiency factor = DC solar system size

For instance, if your daily kWh usage is 34 kWh and you receive around 6.1 hours of sunlight. The result would be:

34kWh/6.1×1.15 efficiency factor =6.4kW DC solar system size required

Now, you can multiply the 6.4 kW number by 1000 (to convert into watts). So you can verify that you will need 6400 watts of solar panels to fulfil your daily energy requirements. 

Solar Battery Sizing

Solar Battery sizing is slightly more complicated than deciding on solar panel size. That’s because the decision on solar batteries relies on how much energy is left to fill them from the solar energy produced by the panels. Therefore, to get the right size of batteries, you first need to understand the amount of energy your household consumes every day and the amount of energy your solar system produces daily.

However, the size of a solar battery is a more personalized matter and depends on your energy goals. If you want to invest in solar batteries to save money or focus on energy independence, you must invest in the right solar battery size. For instance, a large battery will remain underutilized, and a small one will not fulfil your energy goals.

What solar battery size do you need?

To help you find the right solar battery, we have prepared the following table covering the maximum recommended battery sizes for financial purposes and energy independence.

Your Daily power consumptionMaximum recommended battery size for:Solar System Size
5-10kWhMaximum Returns5kWh4kWh4kWh4kWh4kWh
Maximum Energy Independence22kWh35kWh35kWh35kWh
11-15kWhMaximum Returns4kWh7kWh9kWh8kWh8kWh
Maximum Energy Independence40kWh65kWh65kWh
16-20kWhMaximum Returns3kWh6kWh13kWh12kWh11kWh
Maximum Energy Independence55kWh90kWh
21-25kWhMaximum Returns2kWh5kWh12kWh16kWh15kWh
Maximum Energy Independence23kWh70kWh
26-30kWhMaximum Returns1kWh4kWh11kWh18kWh18kWh
Maximum Energy Independence40kWh
31-40kWhMaximum Returns3kWh10kWh17kWh23kWh
Maximum Energy Independence27kWh


Proper sizing of solar panels and batteries is crucial for harnessing the maximum potential of solar systems. This way, you can fulfil your household or business energy needs and become energy independent.

We hope this guide has cleared your doubts. So you can accurately determine the size of your solar panels and batteries according to your needs and goals.

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