Batteries
Battery Specific Power Calculator
The purpose of Battery Specific Power is to turn peak power and battery mass into specific power. Keep the source condition with the saved result so later comparisons remain meaningful.
Run the Battery Specific Power scenario
Replace the examples with values from the same case.
Specific power: calculation method
For this worksheet, the governing relationship is specific power = power ÷ mass. Its variables correspond to Peak power and Battery mass.
The initial scenario returns 140.63 W/kg. Re-enter field data before using the answer in a design or comparison.
Calculate specific power from peak power and battery mass. Amp-Hour Watt-Hour Calculator may be useful for the next related quantity.
How to use the result
The calculated Specific power is meaningful only with its input conditions attached. Compare it with BMS limits, usable energy, current capability, and temperature.
Label alternate cases rather than overwriting the baseline.
Preparing the calculation
Record chemistry, temperature, state of charge, age, and discharge rate. If operating conditions changed between readings, calculate separate cases.
At least one field has a positive lower bound because it appears in a denominator. Use the displayed unit for every field and document conversions separately.
- Peak power
- Default example: 4500 W. Enter peak power in W.
- Battery mass
- Default example: 32 kg. Enter battery mass in kg.
Checks before using the answer
Peak duration and thermal limits must accompany the value.
Additional checks may be needed for chemistry-specific limits and manufacturer test conditions. Document which effects were checked elsewhere in the analysis.
Use voltage and capacity values from the same battery condition.
Keep a reproducible record
Save peak power and battery mass with specific power. Add the date and any unit conversion.
Pass specific power as the raw numerical value until the final step. Do not round between dependent calculations.
Questions from practical use
Should I use measured or nameplate values?
Use peak power and battery mass from one operating condition. 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.
What explains a gap between calculated and observed specific power?
Recheck units and operating state before investigating voltage sag, thermal rise, charge taper, and balancing.
How do I run a useful sensitivity check?
Keep unaffected entries fixed so the cause of the difference remains visible. Separate nameplate capacity from measured usable capacity.
Can I select equipment from this number alone?
Use the number as one check, then review a warm, cold, new, and aged battery case where relevant.