The Secret Formula to Perfect Solar Sizing (Most Installers Don’t Want You to Know
If you’ve ever wondered why some solar installations perform flawlessly while others barely power a fan, here’s the truth most installers won’t tell you: it all comes down to solar sizing.
Yes — the real secret to getting the most from your solar system isn’t in buying the most expensive panels or batteries; it’s in sizing your system perfectly for your energy needs. Most installers skip this step because it takes time, calculation, and accuracy — but the good news? You can now do it yourself using the Globisun Solar Sizing App.
⚡ The Real Reason Solar Systems Fail
Thousands of solar setups fail within months — not because the equipment is bad, but because the system is wrongly sized.
Imagine installing a ₦2 million solar system only to discover your lights flicker and your batteries drain after a few hours. That’s not bad luck; it’s bad load calculation.
Every appliance you use — your TV, freezer, fan, or water pump — consumes power differently. Without properly calculating these loads and matching them to your solar panels, inverter, and batteries, your system will never reach its full potential.
That’s why proper solar sizing is non-negotiable. It determines everything — the performance, longevity, and return on your investment.
☀️ Understanding Solar Sizing
Solar sizing means determining how much solar power you need to meet your energy demand. It involves calculating your total power consumption, then designing your system — panels, batteries, inverters, and charge controllers — to match that demand efficiently.
Think of it as tailoring a suit: one size never fits all. The energy needs of a 3-bedroom home differ drastically from a small office or shop.
With the Globisun Solar App, you can now calculate your exact requirements in minutes without guessing or calling an installer.
🔐 The Secret Formula (Revealed)
Here’s the simple formula most people overlook when doing their load calculation:
Total Load (Watt-hour) = Sum of (Power rating of each appliance × hours used per day)
Example:
| Appliance | Power (W) | Hours/day | Energy (Wh) |
|---|---|---|---|
| TV | 100 | 5 | 500 |
| Fan | 80 | 8 | 640 |
| Bulb (x4) | 15 | 6 | 360 |
| Freezer | 120 | 10 | 1200 |
| Total Daily Load | 2,700 Wh (2.7kWh) |
Now that you know your total daily energy demand (2.7kWh), the next step is to calculate your panel, battery, and inverter size.
⚙️ How to Size Each Component the Right Way
🔹 Solar Panels
You’ll need enough panels to generate more than your daily energy need (to account for inefficiencies).
Formula:
Required solar panel capacity (W) = (Total load × 1.3) ÷ Average sunlight hours
If you live in Lagos or Abuja with about 5 hours of sun daily:
(2,700 × 1.3) ÷ 5 = 702W
So, you’ll need roughly 3 units of 300W panels.
Or simply open the Globisun Solar App and let it do the calculation instantly.
🔹 Batteries
You want enough storage to last through the night.
Formula:
Battery capacity (Ah) = (Total load ÷ system voltage) × days of autonomy ÷ depth of discharge
For our 2.7kWh system using 12V and 1-day backup:
(2,700 ÷ 12) ÷ 0.8 = 281Ah
That’s about two 150Ah batteries.
Again, the Globisun App handles this in seconds and even recommends the best configuration.
🔹 Inverter
Your inverter must handle your total load at once.
Rule of thumb:
Choose an inverter with 25–30% higher capacity than your maximum load.
For a 1.5kW total load, go for a 2kVA inverter.
🔹 Charge Controller
Your charge controller must be able to handle the total current from the solar panels.
Formula:
Controller current = Total solar panel wattage ÷ system voltage
For 900W panels on a 12V system:
900 ÷ 12 = 75A, so you’ll need at least a 75A charge controller.
🔹 Cables
Undersized cables cause voltage drop and power loss. Always use the correct cable gauge. The Globisun Solar Sizing App automatically calculates the right cable size for your distance and current.
🤖 The Easy Way — Let the Globisun App Do It For You
Manual calculations are stressful and prone to errors. But with the Globisun Solar App, all you have to do is:
- Enter your appliances and their usage hours.
- Select your location (the app factors in your sunlight hours).
- Instantly get accurate results for:
- Number of panels
- Battery size
- Inverter rating
- Charge controller size
- Cable recommendations
- You’ll even get daily weather forecasts to plan your solar performance.
It’s your personal solar engineer in your pocket — and it’s 100% free to download.
👉 Stop guessing and start calculating — download the Globisun Solar Sizing App today.
🧭 Final Thoughts — Get It Right from Day One
The “secret formula” isn’t really magic — it’s precision. The installers who seem like geniuses are simply using the right tools and sizing methods.
Whether you’re a homeowner, installer, or solar enthusiast, the difference between failure and success in solar systems is accurate solar system design.
Take the guesswork out of your project — start with the right numbers.
✨ Download the Globisun Solar App now and design your perfect solar system today.
