Engadget Guide: When EV Owners Need a Level 2 Home Charger

The guide notes that an EV is not a smartphone and does not need to start each day at 100 percent. In the United States and Canada, a standard 15A 120-volt AC outlet delivers about 1.8 kW maximum, Engadget says. Used with a standard outlet or portable adapter, that would recharge a plug-in hybrid in under 10 hours, a Fiat 500e with a 38 kW battery in about 21 hours, a Tesla Model 3 in 43 hours and a GMC Sierra EV in 86 hours, or more than 3.5 days.

Battery capacity is the key factor, according to the guide. It lists the Fiat 500e at 38 kW, the Tesla Model 3 at 79 kWh, the Volvo EX30 at 69 kWh, the GMC Sierra EV at 155 kWh, the Toyota Prius Prime at 14 kWh and the Toyota RAV4 Prime at 18 kWh. Maximum AC charging rates also vary: the Prius Prime is limited to 3.5 kW and the RAV4 Prime to 7 kW, while the Nissan Ariya, MG4 and Kia e-Nero are limited to 7.4 kW. Most models including the Tesla Model 3 and Model Y support up to 11 kW.

Daily use is another consideration. If a driver uses only a fraction of the vehicle's range every 24 hours, household power may be enough. But Engadget gives the example of a long route that consumes 40 percent of a Tesla Model 3's battery per day, about 32 kWh or around 100 miles. Fully recharging that on standard household power would take 18 hours. The battery would run down in just a few days, making household power alone insufficient.

Level 2 chargers, the guide says, run on AC power and are available for residential or commercial use. They should not be confused with DC fast chargers. When plugged into a car with either a 5-pin J1772 or Tesla's 5-pin NACS connector, the vehicle converts alternating current to direct current. Level 2 chargers almost always work on a 240-volt circuit rather than 120 volts and can output between 3.3 kW and 11.5 kW on residential systems, depending on the main amperage.

For most plug-in hybrids, Engadget says, owners can save money and charge directly from household power. Drivers with a small battery or those who use less than 15 kWh per day, for a range of around 50 miles, can also stick to a regular outlet and use overnight charging. For anything beyond that, the guide recommends buying a Level 2 charger. A 16-amp, 240-volt model doubles charging speeds to 3.5 kW and halves charging times compared with regular household circuits. A 32-amp, 240-volt charger raises the rate to 7.4 kW, four times more than 120-volt AC power.