Battery Backup Calculator

Follow these simple steps to calculate your inverter battery backup time accurately:

1. Enter Total Load (Watts): Add power of fan, lights, TV, etc.
2. Select Battery Voltage: Choose 12V, 24V, or 48V.
3. Enter Battery Capacity (Ah): Example: 150Ah, 200Ah.
4. Click Calculate: Get instant backup time.
5. Check Result: View estimated inverter backup time.

This battery backup calculator helps you choose the right battery and avoid power backup issues.

To calculate inverter battery backup time, use this simple formula:

Backup Time = (Ah × Voltage × No. of Batteries × Efficiency) ÷ Load

Where:

• Ah = Battery capacity (e.g., 150Ah, 200Ah)
• Voltage = Battery voltage (12V, 24V, 48V)
• No. of Batteries = Total batteries used
• Efficiency = Inverter efficiency (usually 70%–90%)
• Load = Total power consumption in watts

👉 This formula helps you estimate backup time and choose the right battery for your home.

⚠️ Note: Actual backup may vary depending on battery condition, wiring quality, and inverter efficiency.

Use this table to calculate your total load before using the battery backup calculator.

⚠️ Note: Actual power consumption may vary depending on brand and usage.

1. How to calculate inverter battery backup time?

You can calculate battery backup using this formula: Backup = (Ah × Voltage × Efficiency × Battery Count) ÷ Load. Or simply use our battery backup calculator for instant results.

2. Why is my inverter battery backup low?

Low backup can be caused by old battery, high load, low inverter efficiency, or wrong wire size. 👉 For correct wiring, use our Wire Size Calculator .

3. Which battery is best for home inverter?

For home use, 150Ah or 200Ah tubular batteries are commonly recommended for longer backup and durability.

4. What is ideal inverter efficiency?

Most inverters have 70% to 90% efficiency. For calculation, 80% is considered a practical value.

5. How much load can a 150Ah battery handle?

It depends on inverter capacity and usage, but typically a 150Ah battery can handle around 300–500W load for a few hours.

📘 Learn complete electrical wiring: MB Electrical eBook Store

Meet Your Coach

Misba Uddin Barbhuiya

I am the Founder of MB Electrical with 13+ years of experience in the Electrical and Solar field.

🎯 My mission is to provide practical electrical knowledge in simple language for beginners.