One of the most common mistakes people make when going solar is buying the wrong number of panels. Some buy too few and end up with a system that never fully charges the battery. Others buy more than they need and overspend on panels they are not using.
The good news is that calculating how many panels you need is not complicated once you understand the simple logic behind it. This post will walk you through it step by step, using real numbers from a typical Nigerian household.
The Core Question: What Are Your Panels Actually Supposed to Do?
Before calculating how many panels you need, you need to understand their primary job in your solar system.
Your solar panels need to generate enough electricity each day to do two things: power your home during the day and recharge your battery fully so it can power your home at night.
That is the target. Everything else in the calculation flows from there.
Step 1: Calculate Your Daily Energy Consumption
Start by listing every appliance you want to power and estimating how many hours per day you use each one. Then multiply the wattage of each appliance by the hours of use to get watt-hours (Wh) per day.
Example:
- LED TV (80W) x 5 hours = 400Wh
- 2 Standing fans (60W each) x 8 hours = 960Wh
- Refrigerator (150W) x 8 hours effective = 1,200Wh
- LED lighting (60W total) x 6 hours = 360Wh
- Phone chargers and small devices (30W) x 4 hours = 120Wh
Total daily energy consumption: 3,040Wh, or approximately 3kWh per day.
Step 2: Account for System Inefficiency
No solar system operates at 100% efficiency. Energy is lost in the wiring, in the inverter conversion process, and in battery charging and discharging. A realistic efficiency factor for a complete solar system is 75–80%.
To find the gross solar energy you need to generate each day, divide your daily consumption by the efficiency factor:
3,040Wh divided by 0.8 = 3,800Wh (or 3.8kWh) of solar generation needed per day.
Step 3: Find Your Peak Sun Hours
Solar panels only generate power at their rated wattage during peak sunlight conditions. In Nigeria, most regions receive between 4.5 and 6.5 peak sun hours per day, depending on location and season.
For a conservative calculation, use 5 peak sun hours for most parts of southern Nigeria and 5.5 to 6 for northern Nigeria.
Using 5 peak sun hours for our calculation:
3,800Wh divided by 5 hours = 760W of solar panel capacity needed.
Step 4: Choose Your Panel Wattage and Calculate the Number of Panels
Now divide the required solar capacity by the wattage of the panels you intend to buy.
If you are using 530W bifacial panels from KombPower:
760W divided by 530W = 1.43 panels. Round up to 2 panels.
If you are using 380W standard panels:
760W divided by 380W = 2 panels.
For this example household, 2 high-wattage panels would be the minimum. However, it is always advisable to add one more panel as a buffer to account for cloudy days, panel shading, and gradual performance degradation over time.
Revised recommendation: 3 x 530W panels for this household.
How Panel Choice Affects the Number You Need
This is where product selection becomes important. Higher wattage panels mean you need fewer of them to achieve the same output, which also means less roof space, fewer mounting points, and potentially lower installation costs.
KombPower’s solar panel range includes high-efficiency options that maximize output per panel, meaning you get the same or better results with a leaner, cleaner installation.
What About Larger Homes or Businesses?
For homes with air conditioning, the calculation changes significantly. A standard split AC unit (1.5HP) consumes approximately 1,000–1,200W when running. Running it for 6 hours per day adds 6,000–7,200Wh to your daily load — more than doubling the energy needs of the example above.
For commercial properties, offices, and businesses with multiple AC units or heavy equipment, the panel count can rise to 10, 15, or 20+ panels depending on the load. This is exactly why a proper assessment is so important before purchasing.
Conclusion
Solar sizing is not guesswork. It is a straightforward calculation once you have your load numbers. And getting it right from the start saves you from the frustration of a system that underperforms and the cost of buying additional panels after the fact.
Not sure how many panels your home needs? Visit www.kombpower.com or contact our team for a free solar sizing assessment. We will run the numbers for your specific home and recommend the exact configuration: panels, inverter, and battery to meet your energy needs.
