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How to Calculate the Right Battery Size for Your Solar Energy System 19/ 2025.8 月

Choosing the correct battery size for your 太陽能系統 is essential to ensure reliable power supply, maximize efficiency, and avoid unnecessary costs. Here’s a simple guide to help you size your solar battery storage correctly.

1️⃣ Know Your Daily Energy Usage

Check your electricity bills or use an energy meter to find out how many kilowatt-hours (kWh) you consume per day.

Example: If your home uses 20 kWh/day, your battery needs to store at least this amount to cover daily needs.

2️⃣ Decide Your Autonomy Days

How many days do you want the system to run without sunlight?

  • 1–2 days for sunny climates

  • 3–5 days for remote or cloudy areas

Formula:
Battery Capacity (kWh) = Daily Usage × Autonomy Days

3️⃣ Consider Depth of Discharge (DoD)

Batteries can’t be drained completely.

  • Lithium-ion: 80–90% DoD

  • Lead-acid: 50% DoD

Adjust your capacity based on the battery type.

4️⃣ Factor in System Efficiency

Losses occur in inverters and wiring. Multiply your result by 1.1–1.2 for accuracy.

📌 Example Calculation

Daily Usage: 20 kWh
Autonomy Days: 3
Battery Type: Lithium-ion (90% DoD)
Efficiency: 90%

Required Battery = 20 × 3 ÷ 0.9 ÷ 0.9 ≈ 74 kWh

🚀 Bluesun Battery Solutions

Bluesun provides lithium-ion and LiFePO4 battery systems from 5kWh to 1MWh, perfect for residential, commercial, and off-grid projects. Our experts can size your battery based on your exact needs.

👉 Contact us for a free battery sizing consultation.

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