Battery Backup Calculator
Estimate backup time from battery bank voltage, amp-hours, usable depth of discharge and efficiency.
Interactive Electrical Calculator
Battery Backup Calculator
Estimate backup time from battery bank voltage, amp-hours, usable depth of discharge and efficiency.
Result
Enter values and calculate.
How to use this Battery Backup Calculator
Enter the known electrical values above and select the applicable system options. The result updates when you press Calculate. Keep units consistent with the labels shown.
Formula
Runtime = V × Ah × DoD × efficiency / load.
Frequently asked questions
What does this calculator do?
Estimate backup time from battery bank voltage, amp-hours, usable depth of discharge and efficiency.
Can I use the result for final electrical design?
Use the result as a planning or educational estimate. Final wiring, protection, fault-current and equipment selections should be verified against manufacturer data and the electrical code that applies to your installation.
Why can real-world results differ?
Actual systems can be affected by temperature, cable construction, harmonics, equipment efficiency, battery chemistry, starting current, installation method and local code requirements.