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Level 2 charging, explained

Seven questions about Level 2 chargers, each answered from the ENERGY STAR data with its own tables and charts.

• 32, 40, 48 or 80 amps: what the rating changes

  A 48 A charger is rated 11.52 kW against 9.6 kW at 40 A, and 48 A is the most common rating: 134 of 424 Level 2 listings.

• How much power a charger draws when nothing is plugged in

  The median certified Level 2 listing draws 3.66 W with no car connected, about 32 kWh if left that way all year.

• Wi-Fi chargers and chargers with no network connection

  Networked Level 2 listings have a median standby draw of 3.78 W against 2.93 W for the 56 without a network connection.

• What the ENERGY STAR test measures on a charger

  Three readings with no charging under way, each set against an allowance for the charger's feature set.

• Level 2 charging time for common battery sizes

  At an 11.5 kW AC limit, 20 to 80 % of a 75 kWh battery takes about 4 h 21 min at 90 % efficiency.

• Level 1, Level 2 and dual-input chargers side by side

  The 7 Level 1 listings are rated 1.8–1.92 kW at 120 V; most dual-input listings are listed at their 120 V rating.

• Listings that share test values across brands

  117 of 461 listings have reported identical test values in the ENERGY STAR list to a listing under another brand.