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California LocalizedGenerated accuracy model review: 2026-05-06

California EV Charging Cost Calculator accuracy and testing

This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.

Formula source

  • If efficiency is mi/kWh, battery kWh = miles / mi per kWh. If efficiency is kWh/100 mi, battery kWh = miles x kWh per 100 mi / 100. Wall kWh = battery kWh / (1 - charging loss). Monthly cost = wall kWh x rate + sessions x session fee.

Test cases

Default input regression check

Generated from the checked-in default inputs and calculate function.

Inputs

  • Monthly Miles: 900 mi
  • EV Efficiency Preset: tesla_model_y_long_range
  • Efficiency Mode: Miles per kWh
  • Efficiency Value: 3.4
  • Electricity Rate Preset: eia_ca_residential_average
  • Electricity Rate: 0.32 $/kWh
  • Charging Loss: 10%
  • Sessions per Month: 12
  • Session Fee: $0

Expected outputs

  • Estimated Monthly Charging Cost: $85.45

Known limitations

  • This calculator is a planning estimate only. It is not utility, tax, DMV, or transportation advice and does not verify official tariffs, time-of-use windows, demand charges, rebates, idle fees, or exceptions.

Assumptions

  • Electricity rate is user-entered because California tariffs vary widely.
  • Charging loss is modeled as a simple percentage.
  • Session fees are multiplied by sessions per month and added to energy cost.

Unit handling

  • Monthly Miles accepts values in mi.
  • EV Efficiency Preset accepts one of the configured options.
  • Efficiency Mode accepts one of the configured options.
  • Efficiency Value accepts numeric values.
  • Electricity Rate Preset accepts one of the configured options.
  • Electricity Rate accepts values in $/kWh.
  • Charging Loss accepts values in %.
  • Sessions per Month accepts numeric values.
  • Session Fee accepts values in $.
  • Estimated Monthly Charging Cost is displayed as currency.

Rounding rules

  • Number displays use up to 2 decimal places in the calculator UI.
  • Currency outputs are displayed with standard US dollar formatting.
  • Input precision follows configured step values where provided.

Version history

1.0.0 - 2026-05-06

Generated accuracy and testing page from the current california-ev-charging-cost-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for California EV Charging Cost Calculator.

Calculator transparency

Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.

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