🔋 Battery Backup Calculator

UPS/Inverter backup time, EV Bike battery backup, or EV Car battery backup & range — all in one place.

Enter the capacity of one battery in Ah. Example: 100 Ah, 150 Ah, 200 Ah.
Enter the voltage of one battery. Common values are 12V, 24V and 48V systems.
Enter how many batteries are connected to your inverter/system.
Enter the total power consumption of all appliances running together.
If you are unsure, 80–90% is a reasonable general estimate.
This accounts for the percentage of battery capacity that you actually use.
Estimated Backup Time
0 hrs 0 mins
(0 hours)
Total Battery Energy 0 Wh
Usable Energy 0 Wh
Battery Bank 0 V
Backup Time = (Battery Ah × Battery Voltage × Number of Batteries × Efficiency × Usable Capacity) ÷ Total Load
⚠️ This calculator provides an estimated backup time. Actual backup can vary depending on battery age, temperature, battery type, inverter performance, wiring losses and actual appliance load.

EV Bike / Scooter Battery Backup Details

Example: most electric scooters use 2–4 kWh batteries.
Lower Wh/km means better efficiency. Typical scooters: 25–45 Wh/km.
Battery percentage actually used before recharging.
Enter your electricity price per unit.
Typical charging loss is around 5–15%.
Used to estimate daily charging cost.
Estimated Backup Range
0 km
on usable battery charge
Full Charge Cost ₹0
Cost Per KM ₹0
Daily Charging Cost ₹0
Monthly Estimate ₹0

📊 Battery Summary

Your EV bike/scooter can travel approximately 0 km on a usable battery charge.

Backup Range = (Usable Battery kWh × 1000) ÷ Efficiency (Wh/km)
* Estimates are approximate. Actual range depends on speed, traffic, riding style, temperature, tyre pressure, payload and road conditions.

EV Car Battery Backup Details

Example: compact EVs 30–45 kWh, long-range EVs 60–100 kWh.
Lower Wh/km means better efficiency. Typical EV cars: 130–180 Wh/km.
Battery percentage actually used before recharging.
Enter your electricity price per unit.
Typical charging loss is around 5–15%.
Used to estimate daily charging cost.
Estimated Backup Range
0 km
on usable battery charge
Full Charge Cost ₹0
Cost Per KM ₹0
Daily Charging Cost ₹0
Monthly Estimate ₹0

📊 Battery Summary

Your EV car can travel approximately 0 km on a usable battery charge.

Backup Range = (Usable Battery kWh × 1000) ÷ Efficiency (Wh/km)
* Estimates are approximate. Actual range depends on speed, traffic, driving style, temperature, tyre pressure, payload and road conditions.

Battery Backup Calculator: Estimated UPS, Inverter & EV Range Instantly

Running out of power at the wrong moment is frustrating-whether it’s your inverter dying during a blackout or your electric scooter losing change Halfway through a ride. A battery backup calculator takes a guesswork out of power planning by Showing you exactly how long your battery will be before you need it.

What Is a Battery Backup Calculator?

A battery backup calculator is free online tool that estimates how to longs a battery can power a device or voltage, and the load connected to it. Instead of manually calculating watt-hours and efficiency losses, you simply enter your battery specifications and get an instant, accurate result.

This tool useful for three common situations:

Home UPS or inverter backup – knowing how to long your battery bank will run your lights, fan, or fridge during a power cut.

EV bike or scooter range – estimating how far you can ride on a full charge.

EV car battery backup – calculating driving range and daily charging cost.

Battery Backup Calculator
Battery Backup Calculator

How the UPS/Inverter Backup Calculator Works

For inverter and UPS system, backup time depends on four key factors: battery capacity (AH), battery voltage (V), number of batteries connected, and your total connected load in watt. The calculator also factors in inverter efficiency and usable battery capacity, since no battery discharges 100% of its rated energy in real-world use.

The formula used is:

Backup Time = (Battery AH × Voltage × Number of Batteries × Efficiency × Usable Capacity) ÷ Total Load

For example, a 150Ah, 12V battery running a 300-watt load at 90% efficiency and 90% usable capacity gives routers 4.5 hours of backup – a number that world take several manual steps to calculate otherwise.

How the EV Bike & Car Battery Backup Calculator Works

Electric vehicles work differently. Instead of watts and amp-hours, EV range depends on battery capacity in kWh and energy Efficiency in Wh/km. The calculator also accounts for charging losses and electricity rates, so you get a complete picture: estimated range, cost per kilometer, daily charging cost, and monthly electricity expenses.

Range = (Usual Battery kWh × 1000) ÷ Efficiency (Wh/km) 

A typical electricity scooter with a kWh battery and 35 Wh/km Efficiency can travel about 77km on a full usable charge, while an EV car with a 40 kWh battery and 150Wh/km efficiency covers roughly 240 km.

Battery Backup Time Calculation Table

Battery Capacity          100w Load              200W Load       300W Load             400W Load

(AH)                     (Laptop + Router)     (Fans + LED)     (TV + 2 Fan +Light) (Fridge-PC)      

100 AH                           9.6 Hours                4.8 Hours             3.2 Hours                     2.4 Hours

120 AH                           11.5 Hours               5.8 Hours             3.8 Hours                     2.9 Hours

150 AH                           14.4 Hours               7.2 Hours            4.8 Hours                     3.6 Hours

180 AH                           17.3 Hours               8.6 Hours            5.8 Hours                     4.3 Hours

200 AH                           19.2 Hours               9.6 Hours            6.4 Hours                     4.8 Hours

200 AH                           19.2 Hours               9.6 Hours            6.4 Hours                     4.8 Hours

220 Ah                           21.1 Hours               10.6 Hours           7.0 Hours                     5.3 Hours

Frequently Asked Questions

Does battery age affect backup time?

Yes, Older batteries loss capacity over time, so actual backup will be lower than a brand-new battery’s rated performance.

Why is usable capacity less than 100%?

Discharging a battery full especially lead-acid types, shortens its lifespan. Most manufactures recommended using 70-90% of rated capacity for longer battery health.

Can I use this for solar battery backup?

Yes, the same Ah × Voltage formula applied to solar battery banks, as you know total connected load.

Whether you’re a home inventor, planning an EV commute, or comparing battery options before a purchase, a reliable battery backup calculator saves time and prevents unpleasant surprise. Try the calculator above to get instant, accurate backup time and range estimates for your specific setup.