Solar panels are a great way to generate clean and renewable energy for your home or business. But how do you know how many panels you need and what size they should be?

This post covers two topics:

• How to size solar panels: Learn the basics.
• How to pick the best solar panels: Get tips for choosing what suits you.

Solar Panel Output and Quality

Solar panels are sold according to their output capacity, measured in watts (W). The output capacity indicates the electricity the panel can produce under ideal conditions. The more power the panel can generate depends on the higher the output. 

However, the output capacity is not the only factor affecting the panel's performance. The panel's quality also matters. A good solar panel works well even when:

• Sunlight changes
• It gets hot or cold

High-quality panels are more efficient and durable. They can make almost all the power they're supposed to in perfect conditions. Plus, they keep working well for a long time. Low-quality panels, on the other hand, may have lower efficiency and degrade faster. They may produce only 70% or less of their rated output in ideal conditions and lose more power over time.

Therefore, the vital thing to note is that the higher the quality of the panel you buy, the more power it produces. It's not the number of panels that matters; it's the output you can get from them. Two high-quality panels in one installation may outperform ten low-quality ones in another.

How to Size Your Solar Panels Based on Your Energy Needs

Step 1:Find out how much power you use daily.

You can do this by performing an energy audit, which measures and records your daily power usage. A power meter or an online tool can help you with this. If your solar panels are 90% efficient, multiply your daily energy use in watts by 1.1. Make sure you note the maximum input that the inverter you want to use can take. You do not want more output than the manufacturer's maximum output set for your inverter.

This number does not cover power loss in a few ways:

• Bad wiring
• Inverter problems
• Battery issues

Daily Consumption x 1.1 = Output required from PV panels. 

For example, your home needs 800 watts per hour. An 800 x 1.2 = 960 watt panel might be sufficient. This article is just a guide. Always reach out to us so we can understand your specific situation. 

Step 2: Consider the Peak Sun Hours

You need to know how many hours of peak sun you get. This is when your solar panels make the most power. The peak sun hours depend on the location, season, and weather. In southern Nigeria, you get 4-5 hours of peak sun. In the north, it's about 7 hours. It's best to size your solar panels for the least amount of sun. This ensures they can fully charge your batteries and give you enough power, even on cloudy days. However, keep the maximum PV input your inverter can take into account.

Here's a simple way to estimate how many solar panels you'll need:

1. Multiply your daily watt usage by 3.43.
2. Divide the result by the wattage of a single solar panel (in watts).
3. The answer is the estimated number of panels required.

Example:

You can use your hourly energy needs to calculate the ideal number of solar panels required-

Daily energy requirement = 3000 Watts

Safety factor = 1.3

Total PV output required = 3000 Watts x 1.3 = 3900 Watts

Proposed Panel wattage = 400 Watts

Now, calculate the number of panels needed:

Number of panels = Total PV output required / Proposed Panel wattage

= 3900 Watts / 400 Watts

≈ 9.75 panels

This shows how many panels you need to make enough power during peak sun hours. But you might have a big battery bank. If so, you might need even more panels to charge it daily. Hence, this method can only work for small-budget systems.  This is just an estimate. To find the correct number of solar panels, check your inverter. See what its voltage and maximum power are. This will tell you how many panels your inverter can handle.

Conclusion

Solar panel sizing is an essential step in designing your solar system. This helps your system work better and use less energy. Buying the correct number of solar panels saves you money and resources. You don't want to buy too many or too few. Use our tips and formula to find out how many panels you need. Then, choose the best quality panels for your home.