Formula Explanation
Runtime = Ah x V x DoD x efficiency / load
This calculator applies the formula Runtime = Ah x V x DoD x efficiency / load. Enter each value with the matching unit, and AZCalculate updates the result instantly.
Engineering
Battery Backup Calculator
Use this battery backup calculator to calculate estimate battery runtime from capacity, voltage, load, efficiency, and depth of discharge.
battery backupruntimecapacityinverter
Calculator
Calculate instantly
Calculator Inputs
Choose what you want to calculate, enter realistic values, adjust units where shown, and use the scenario section for repeated-use planning.
Input and Formula Breakdown
This calculator applies the formula Runtime = Ah x V x DoD x efficiency / load. Enter each value with the matching unit, and AZCalculate updates the result instantly.
Battery capacity
200 Ah
Battery voltage
12 V
Depth of discharge
80 %
System efficiency
90 %
Load
500 W
Runtime
3.46 hours
Usable energy
1,728 Wh
Scenario and Comparison
Current
3.46 hours
Projected
41.47
Adjusted
3.8
Visual Comparison
Current result3.46
Projected usage41.47
Comparison scenario3.8
Sign in to save this calculation and access it later.
Use Cases
- Plan backup power
- Size batteries
- Compare runtime scenarios
Step-by-Step Explanation
- Step 1Enter the known values in the calculator fields.
- Step 2Keep the units consistent with the labels shown beside each input.
- Step 3Apply the formula: Runtime = Ah x V x DoD x efficiency / load.
- Step 4Review the primary result and supporting values.
Example calculation
Example battery backup calculator
Given
- Battery capacity: 200 Ah
- Battery voltage: 12 V
- Depth of discharge: 80 %
- System efficiency: 90 %
- Load: 500 W
Steps
- Use the values shown above.
- Apply Runtime = Ah x V x DoD x efficiency / load.
Result
The calculator above shows the computed answer instantly from these example values.
Calculator guide
About this Battery Backup Calculator
Estimate battery runtime from capacity, voltage, load, efficiency, and depth of discharge. This page includes an interactive calculator, concise formula notes, worked examples, FAQs, related calculators, and practical guidance you can revisit whenever needed.
Found something that does not look right?
We work hard to keep every calculator accurate and useful. If you notice a calculation error, missing option, or unclear explanation, please let us know so we can review and correct it promptly.
Calculator usage
See how many people are using this calculator.
Total visits today
0
Live users now
0
Total saved calculations
0
Most active date
2026-06-05
FAQ
Battery Backup Calculator FAQs
How does the battery backup calculator work?+
It uses Runtime = Ah x V x DoD x efficiency / load and calculates the result from the values you enter.
Can I copy or print the result?+
Yes. AZCalculate calculator pages include copy, share, and print actions.
Related tools
Related Calculators
Engineering
Estimate inverter size from continuous load, surge load, and safety factor.
Engineering
Calculate electrical load from voltage, current, power factor, and quantity.
Engineering
Estimate equivalent bearing load from radial and axial loads.
Engineering
Calculate power factor from real power and apparent power.
Engineering
Estimate heat load from area, heat gain factor, occupants, and equipment.
Engineering
Estimate required cable area from current, allowable density, and safety factor.