Electric Vehicle Charging for Dummies

This guide explains the basic units of electricity used in electric vehicle (EV) charging, arguing that understanding kilowatts (kW) and kilowatt-hours (kWh) is more accurate than relying on manufacturer estimates of range per hour of charging, which vary by vehicle and conditions.

• The document defines a kilowatt (kW) as a "rate of energy flow," comparable to gallons per minute from a hose, while a kilowatt-hour (kWh) is a "quantity of electricity," comparable to a gallon of water in a bucket.
• EV charging stations are categorized into levels with varying power ratings: Level 1 (standard US wall outlets) provides about 1 kW; Level 2 (home stations) typically ranges between 7 kW and 19 kW; Level 3 or DCFC (older public fast-chargers) may deliver 50 kW; and state-of-the-art public fast-chargers can deliver 150 kW or more.
• The actual rate of power an EV receives during charging is not constant; it starts at the maximum rate allowed by the vehicle's charge controller and slows down to a "trickle" as the battery becomes almost full.
• The document argues that describing charger power in terms of "miles of range" per hour is inconsistent because efficiency varies by vehicle, weather, driving habits, and climate control use. For example, a Nissan LEAF with a 40 kWh battery can potentially achieve a similar range to a Tesla Model X with a 100 kWh battery if the LEAF is driven more efficiently (5 miles per kWh versus 2.5 miles per kWh).

APA

RMI (2019). Electric Vehicle Charging for Dummies. https://rmi.org/resources/electric-vehicle-charging-for-dummies/

Chicago

RMI. Electric Vehicle Charging for Dummies. 2019. https://rmi.org/resources/electric-vehicle-charging-for-dummies/.

Wikipedia

{{cite report |author=RMI |title=Electric Vehicle Charging for Dummies |date=10 June 2019 |url=https://rmi.org/resources/electric-vehicle-charging-for-dummies/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2019electric, author = {{RMI}}, title = {{Electric Vehicle Charging for Dummies}}, institution = {RMI}, year = {2019}, month = jun, url = {https://rmi.org/resources/electric-vehicle-charging-for-dummies/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }