Battery Backup Calculator – Find Inverter & UPS Backup Time

If you’ve ever wondered “Meri inverter battery kitne ghante chalegi?” then you’re not alone. Whether it’s for your home inverter, UPS system, or even a solar setup, knowing the exact battery backup time is very important.

With this guide and the free Battery Backup Calculator, you can quickly calculate backup time in hours by entering just three details:

🔹 Load (Watt)

🔹 Battery Capacity (Ah)

🔹 Voltage (V)

If you want to understand inverter setup in detail, check our Inverter Installation Guide

Free Battery Backup Calculator

Enter the details and click Calculate to find your backup duration:


Formula for Battery Backup Time

Backup Time (Hours) = (Battery Capacity (Ah) × Battery Voltage (V)) ÷ Load (Watts)

⚠️ Note: Actual backup time is usually 70–80% of calculated value because of inverter losses & battery efficiency.

New to electrical load calculation? Read our step-by-step Electrical Load Calculator Guide.

Battery Backup Time Calculation Table

Here’s a quick reference battery backup time calculation table (assuming 12V battery and 200W load):

Battery Size (Ah)Voltage (V)Load (Watt)Approx Backup Time (Hours)
100 Ah12V200W6.0 Hours
120 Ah12V200W7.2 Hours
150 Ah12V200W9.0 Hours
180 Ah12V200W10.8 Hours
200 Ah12V200W12.0 Hours

This makes it easy to compare different battery sizes and plan your power needs.

Example: 150Ah Battery Backup Time Calculator

Let’s calculate for a 150Ah, 12V battery with a 200W load:

Backup Time = (150Ah × 12V) ÷ 200W = 9 Hours

So, with a 150Ah inverter battery, you can expect around 8–9 hours of backup for a 200W load.

Why Use a Battery Backup Calculator?

✔ Easy inverter battery backup calculation
✔ Helps select the right battery size
✔ Prevents overloading & battery damage
✔ Saves money by avoiding oversized batteries

A battery backup calculator is the simplest way to estimate how long your inverter or UPS will last during a power cut. By understanding the relationship between battery capacity, voltage, and load, you can make smarter decisions for your home, office, or business.

Try our calculator today and use the battery backup time calculation table for quick reference. Whether it’s 150Ah battery backup or higher, you’ll always know your power availability in advance. Explore inverter battery options on Exide Official Website.