EV Charger Diversity Factor Calculator

Estimate the diversity factor across EV chargers by comparing the summed nameplate ratings against the adjusted coincident peak demand, accounting for planning allowances and offline spares.

Add the maximum kW rating for each EVSE on the panel or feeder.
Highest simultaneous kW draw observed or modelled across the depot.
Defaults to 0%. Use to inflate coincident demand for growth or telemetry uncertainty.
Defaults to 0%. Represent chargers intentionally idled or redundant circuits.

Engineering planning aid; confirm with local electrical codes and demand charge tariffs before final design decisions.

Examples

  • Total nameplate 420 kW, coincident peak 230 kW, 10% allowance, 5% spares ⇒ Diversity factor 1.75 with 57.14% concurrency and 253.00 kW adjusted coincident load.
  • Total nameplate 288 kW, coincident peak 180 kW, allowances left blank ⇒ Diversity factor 1.60 with 62.50% concurrency and 180.00 kW adjusted coincident load.

FAQ

What does the diversity factor tell me?

It quantifies how much higher the summed charger nameplate load is relative to the observed coincident draw so you can size feeders, transformers, and tariffs realistically.

How should I pick the planning allowance?

Use historical variability, telemetry confidence intervals, or near-term growth forecasts—many fleets add 5–15% to reflect measurement noise and organic expansion.

Why remove offline spares?

Chargers reserved for redundancy or maintenance rotation do not contribute to simultaneous demand, so subtracting their nameplate power keeps the ratio aligned with operational reality.

Can diversity be below 1?

Yes. A value below 1 indicates coincident demand exceeds the effective nameplate, signalling telemetry errors or that chargers are configured above listed ratings.

Additional Information

  • Result is unitless but commonly reported as a ratio such as 1.7:1.
  • Concurrency is calculated as the inverse of the diversity factor; values above 100% indicate telemetry or labelling issues.
  • Adjusted coincident demand inflates telemetry by the planning allowance and removes offline spares from the nameplate sum.

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