Battery duty cycle and lifetime
Duty-cycle current, conversion losses, capacity derating, Peukert load rate and self-discharge.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Model: Ibat=Iload Vload/(ηVbat)+Iq; Qusable=Qnom×retention factors; Peukert drain=Σ duty·Iref(I/Iref)^k; t=ln(1+λQ/Ieq)/λ.
Assumptions
- Average battery voltage and regulator efficiency are fixed. Peukert exponent is mainly applicable to lead-acid and must come from battery measurements; k=1 gives ideal coulomb counting.
- Duty-state Peukert drain is a screening approximation without recovery effects. Self-discharge is exponential in remaining usable charge; cutoff is represented by the usable-capacity factor.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Rated battery capacity
- 2 Ah
- Average battery voltage
- 3.7 V
- Regulated load voltage
- 3.3 V
- Sleep current at load
- 0.00001 A
- Active current at load
- 0.02 A
- Transmit current at load
- 0.1 A
- Active duty excluding TX
- 5 %
- Transmit duty
- 1 %
- Regulator efficiency
- 90 %
- Regulator battery-side quiescent current
- 0.000002 A
- Temperature capacity retention
- 90 %
- Ageing capacity retention
- 90 %
- Usable depth/cutoff capacity
- 80 %
- Peukert exponent (1 disables)
- 1
- Capacity rating discharge period
- 20 h
- Self-discharge per 30 days
- 2 %
Results
- Estimated runtime
- 644.319 h
- Average load current
- 0.0020094 A
- Average battery current
- 0.0019933 A
- Derated usable capacity
- 1.296 Ah
- Estimated runtime
- 26.8466 days
- Rate-adjusted equivalent drain
- 0.0019933 A