Hydrogen Electrolyzer & Fuel Cell Manufacturing worked example

Cell Voltage Variation at 1.44% target out-of-spec cell rate: a worked example

Suppose target out-of-spec cell rate falls to 1.44%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate the share of cells in a stack that fall outside the cell-voltage spec window from the count of out-of-spec cells against the total cell count, with a target out-of-spec rate.

The inputs for this scenario

  • Cells outside the cell-voltage spec window: 3 cells (held at the documented default)
  • Total cells in the stack: 100 cells (held at the documented default)
  • Target out-of-spec cell rate: 1.44 % (the input this scenario stresses; the baseline uses 2)

Working through the calculation

  • The calculation starts from the formula this tool documents: Out-of-spec cell rate = cells outside spec ÷ total cells in stack × 100.
  • Out-of-spec cell rate works out to 3 % at these inputs, and this is the headline figure for the scenario.
  • Cell voltage spec gap works out to -1.56 points at these inputs.
  • Cells outside spec window works out to 3 count at these inputs.
  • Total cells in stack works out to 100 count at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target out-of-spec cell rate sits at 2% and the headline result is 3 %, this scenario lands almost exactly on the baseline at 3 %.
  • It computes the percentage of cells outside the voltage spec window and the gap between that rate and your target out-of-spec rate. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Out-of-spec cell rate: 3 % (headline result)
  • Cell voltage spec gap: -1.56 points
  • Cells outside spec window: 3 count
  • Total cells in stack: 100 count

Run it with your numbers

  • To rerun this with your own numbers, open the live Cell Voltage Variation calculator, set target out-of-spec cell rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.