FieldengElectrical & Power
Battery Runtime
Estimate how long a battery can operate a load.
Electrical & PowerEngineering Fundamentals
Estimate how long a battery can operate a load.
App id: ELEC-17. Reference version 1.0.
How to fill it
Fill the inputs. The tool shows the outputs.
On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.
Formula
t = (Ah × usable × η) / IInputs
| Name | Unit |
|---|---|
| Battery capacity | Ah |
| Load current (optional, camera) | A |
| Battery voltage (optional, camera) | V |
| Load power (optional) | W |
| Usable capacity (optional) | % |
| System efficiency (optional) | % |
Outputs
| Name | Unit |
|---|---|
| Estimated runtime (hero result) | h |
| Usable capacity | Ah |
| Stored energy | Wh |
| Usable delivered energy | Wh |
Diagnose
Observations are context. They do not pass or fail a structure. See Diagnose.
Screening bands in the app: < 50% · 50–80% · ≥ 80%.
| When | Observation | Severity |
|---|---|---|
usable ≥ 0.8 | Good estimated usable capacity | info |
usable ≥ 0.5 | Reduced usable capacity | caution |
usable < 0.5 | Low usable capacity assumption | warning |
Assumptions
- Enter load current, or battery voltage with load power.
- Usable fraction and efficiency default to 100% when left blank.
Provenance
- Runtime is an estimate. Discharge rate, temperature, age, and chemistry are not modeled.