Batteries
Peukert Battery Runtime Calculator
This calculator evaluates peukert runtime for a single batteries scenario. It uses rated capacity, rated discharge time, load current, and peukert exponent and shows the equation behind the displayed value.
Set up the Peukert Battery Runtime case
Check the source and units before calculating.
Before entering values
Use voltage and capacity values from the same battery condition. Nameplate and meter values are not interchangeable unless they describe the same condition.
At least one field has a positive lower bound because it appears in a denominator. Confirm decimal placement whenever a source uses a different unit scale. The broader analysis may also use Off-Grid Battery Bank Calculator.
- Rated capacity
- Default example: 100 Ah. Enter rated capacity in Ah.
- Rated discharge time
- Default example: 20 h. Enter rated discharge time in h.
- Load current
- Default example: 20 A. Enter load current in A.
- Peukert exponent
- Default example: 1.15. Enter peukert exponent.
Peukert runtime: calculation method
Here, Peukert runtime is obtained from t = H × (C ÷ (H × I))^k. Only Rated capacity, Rated discharge time, Load current, and Peukert exponent enter the numerical result.
The initial scenario returns 4.06 h. Re-enter field data before using the answer in a design or comparison.
Estimate lead-acid runtime using capacity, rated discharge time, load current, and Peukert exponent. For the companion discharge C-rate calculation, open Battery C-Rate Calculator.
Transferring the result
Archive rated capacity, rated discharge time, load current, and peukert exponent with peukert runtime. Identify the instrument, rating, or assumption behind each entry.
Carry peukert runtime before applying any display rounding. Keep a separate displayed value if reporting precision differs.
What the number means
The calculated Peukert runtime is meaningful only with its input conditions attached. Compare it with BMS limits, usable energy, current capability, and temperature.
Keep the input set beside the output so another reader can reproduce it.
Common entry mistakes
Mixing nominal and measured data is a common source of error.
Check the input source before adding a safety or correction factor.
What the formula leaves out
Peukert behavior varies with battery chemistry, temperature, age, and discharge range.
The arithmetic intentionally leaves out temperature, cell imbalance, BMS cutoffs, aging, and rate dependence. Document which effects were checked elsewhere in the analysis.
Use voltage and capacity values from the same battery condition.
Before relying on the answer
Which source values should I use for Peukert runtime?
Choose entries that describe the same case. Separate nameplate capacity from measured usable capacity.
What is not captured by this equation?
The result follows the displayed variables. Check temperature, cell imbalance, BMS cutoffs, aging, and rate dependence separately.
Why might a second instrument give another answer?
Recheck units and operating state before investigating voltage sag, thermal rise, charge taper, and balancing.
What should remain fixed in an alternate case?
Change one uncertain entry at a time and preserve the baseline. Record chemistry, temperature, state of charge, age, and discharge rate.
Does the answer include a design margin?
The calculator does not approve equipment or supply an unexplained margin. Compare against BMS limits, usable energy, current capability, and temperature.
How much precision should I keep?
Keep full precision while transferring peukert runtime; round only at the final reporting or selection step.