How to Size a Solar System for a Philippine Sari-Sari Store or Small Business

Small businesses — sari-sari stores, carinderia, barbershops, repair shops, small offices — are excellent solar candidates. They operate during daylight hours (peak solar production), have predictable loads, and pay commercial electricity rates. A correctly sized solar system can deliver payback in 4-6 years.

Step 1: Audit Your Business Loads

Step 2: Calculate Required System Size

For a sari-sari store using 6 kWh/day of daytime load:

• Required solar output: 6 kWh ÷ 4.5 PSH ÷ 0.80 system efficiency = 1.67 kW minimum
• Recommended system: 3 kW (provides buffer and handles peak loads)
• Using 6 × 500W panels + 3kW inverter
• No battery needed if store operates only during daylight hours

Financial Case for a 3kW Small Business System

• System cost: ₱100,000–140,000 installed
• Monthly electricity bill (before solar): ₱4,000–8,000
• Solar covers 60-80% of daytime bill: Saves ₱2,400–6,400/month
• Payback period: 2–5 years depending on consumption
• 25-year total savings: ₱720,000–1.9M

Special Consideration: Business Hours vs Solar Hours

If your business operates 24/7 (common for convenience stores with refrigerators running overnight), you'll need a battery system to capture daytime solar for overnight use. Add a 5-10 kWh LiFePO4 battery: approximately ₱70,000–120,000 additional cost.

Getting Started

Share your latest Meralco bill and business operating hours with a solar installer. A proper load analysis takes 30 minutes and gives you an accurate system recommendation. Don't let installers upsell you to a larger system than you need.

Find installers specializing in small business solar at solarenergyph.shop — free quotes, no obligation.

Engr. Jason Morales — Founder, SolarEnergyPH