Constant Power Battery Voltage Sag Calculator
Solve a Thevenin battery’s high-voltage constant-power operating point and internal resistive heat.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Solve the quadratic voltage/power balance and retain the high-terminal-voltage branch.
Terminal V=(Voc+√(Voc²−4RP))/2; current=P/V; internal loss=I²R
Worked example
Voc=12 V and R=0.1 Ω have ideal maximum transferable power 360 W. Requested power above that has no real steady solution in this model.
Assumptions and input details
Fixed open-circuit voltage and resistance, one mathematical operating branch. No state of charge, dynamic load stability, temperature, current rating, cutoff or actual battery protection model. The maximum-transfer limit is theoretical, not an acceptable operating recommendation.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
SI prefixes are explicit: for example, milli means one thousandth, micro one millionth and kilo one thousand. Changing a unit changes the interpretation of the entered number.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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