Battery Runtime Calculator
Calculate battery runtime with transparent engineering inputs and the displayed formula.
Run deterministic checks for missing or mixed units, physical bounds, detectable out-of-range values and formula applicability. This is not an engineering approval or a complete code/compliance check.
Export the current calculation inputs and outputs with formula, assumptions, confirmed source credits, automated verification status, tool version and timestamp.
PROFENG Pro unlocks calculation-record exports. The calculation itself remains free.
PROFENG provides this tool for engineering screening and educational use. Check the calculation basis, units, physical assumptions, applicable standards, safety factors, equipment data and project-specific requirements before design, procurement or operation.
Turn this result into a calculation record
Carry the tool context into the PROFENG calculation-check and record workspace without implying certification or engineering approval.
Why use this battery runtime calculator?
Calculate battery runtime with transparent engineering inputs and the displayed formula. The displayed relationship is t = V Ah η / P.
What this calculation does
This calculator determines estimated runtime from battery voltage, battery capacity, usable efficiency, load power. Use it for transparent electrical screening calculations before equipment selection, protection studies or detailed circuit analysis.
Formula and engineering variables
t = V Ah η / P
| Variable | Definition | Unit | Working guidance |
|---|---|---|---|
voltage | Battery voltage | V | Illustrative screening band: 0 to about 480 V. This is not a design limit. |
capacity | Battery capacity | Ah | Illustrative screening band: 0 to about 1,000 Ah. This is not a design limit. |
eta | Usable efficiency | % | Physical screening range: greater than 0% and no more than 100%. |
load | Load power | W | Illustrative screening band: 0 to about 10,000 W. This is not a design limit. |
Ranges above are screening guidance or physical bounds where stated. They are not code limits or manufacturer ratings.
Calculated outputs
- Estimated runtime (h): voltage*capacity*(eta/100)/load
Worked example
- Battery voltage (voltage) = 48 V
- Battery capacity (capacity) = 100 Ah
- Usable efficiency (eta) = 85 %
- Load power (load) = 1,000 W
(48)*(100)*((85)/100)/(1000) = 4.08 hEstimated runtime: 4.08 hAssumptions
- The entered quantities describe the same electrical operating state.
- AC quantities are interpreted using the formula's stated phase and power-factor assumptions.
- Nominal values do not represent transient, fault or harmonic behavior unless explicitly included.
Limitations
- Protection, conductor ampacity, harmonics, starting duty, insulation coordination and equipment ratings require separate checks.
- Final electrical design must follow the applicable installation and equipment standards.
- Voltage and usable capacity are treated as constant equivalent values.
- The load is treated as constant.
- Battery discharge-rate effects, voltage sag, temperature, inverter behavior and manufacturer cutoff limits are not modeled.
- The displayed default values are a worked example only; replace them with traceable project or measurement data.
Formula source and acknowledgement
Source being confirmed. PROFENG has not yet approved a published source for this exact implementation, so no candidate book, paper or standard is displayed here.
Limits of use for this relationship
- Voltage and usable capacity are treated as constant equivalent values.
- The load is treated as constant.
- Battery discharge-rate effects, voltage sag, temperature, inverter behavior and manufacturer cutoff limits are not modeled.
Read the PROFENG methodology for formula sourcing and automated checks →
How to use it
Start with the inputs shown above, review the assumptions or options, then generate the result. Where the tool creates a file, keep the original until you have opened and checked the downloaded output.
Frequently asked questions
What does Battery Runtime Calculator calculate?
This calculator determines estimated runtime from battery voltage, battery capacity, usable efficiency, load power. Use it for transparent electrical screening calculations before equipment selection, protection studies or detailed circuit analysis.
What formula does Battery Runtime Calculator use?
The calculator uses t = V Ah η / P. Every input used by the implementation is listed in the variable table on this page.
How is the worked example for Battery Runtime Calculator checked?
PROFENG substitutes the displayed default values into the implemented relationship and compares the result against automated verification cases where an independent verifier is available.
What assumptions matter most for Battery Runtime Calculator?
The entered quantities describe the same electrical operating state. AC quantities are interpreted using the formula's stated phase and power-factor assumptions. Nominal values do not represent transient, fault or harmonic behavior unless explicitly included.
Can I use this result for final design or procurement?
Use it as an engineering screening calculation. Final design, procurement, operation or compliance decisions require project-specific data and the applicable engineering method, standard or manufacturer information.
QA, changelog and corrections
Last QA update: 30 September 2026.
Automated verification passed – 30 September 2026 – six numerical cases checked, with dimensional checks, independent cross-checks for calculators, and unit round-trip checks for converters where applicable.
Changelog
30 September 2026 – source/indexation status, metadata and correction pathway reviewed. Engineering tools display the automated verification label only when they are inside the passing Part 3 verification scope.