Can I adapt a 120-volt EV charger to use a 240-volt connection? Emporia’s promising EV charger and home energy management system (Week 44, 2022)

Sound Advice
By Don Lindich

Week 44, 2022

Q. In a recent column you answered a question about a Hanasco toothbrush charging with different USB chargers. You said, “This scenario is pretty common with charging sources and devices that use a similar connection but with different charging capabilities, including plug-in electric vehicles, something of which many in the public are unaware.”

My Toyota RAV4 Prime (plug-in hybrid) included a 120-volt charger. Can I adapt the 3-prong plug and use it with a 240-volt NEMA 6-15R outlet?

-M.S., Alamo, CA

A. The included Toyota charger is not designed to work with 240V, and the cord is likely not thick enough to carry the extra power even if the plug was changed to a 240V version. There are numerous portable EV chargers that work with both 120V and 240V power, but they require changing the cord and plug depending on voltage. The cord and plug are usually a single interchangeable piece with the appropriate plug and correspondingly thick cable. We will cover this after an explanation of 120V (Level 1) and 240V (Level 2) vehicle charging.

Level 1 charging uses a 120V charger connected to an ordinary 3-prong electrical outlet. They typically add 3 to 4 miles of range for every hour of charging. With PHEVs maxing out at around 30 to 40 miles of pure electric range, an overnight charge with a Level 1 charger is usually enough for most owners. A 2022 RAV4 Prime has 42 miles of all-electric range so if you plug in your car at 8 PM it should be fully charged by 7 AM the next morning. (Charging slows down as the battery fills up.) The biggest benefit to Level 2 charging for PHEVs is the ability to quickly charge your car throughout the day. For example you could run 25 miles of errands in the morning, come home and plug in and a few hours later leave with a full charge again.

Level 2 charging uses a 240V charger, but there is more to consider than 240V. Level 2 chargers come in a wide array of amperage (A) capability and the difference in charging speed is profound. Charging provider ChargePoint lists a 16A Level 2 charger as providing an estimated 12 miles per hour of charging, and a 40A Level 2 charger at an estimated 30 miles per hour of charging. It is easy to assume that plugging in any 240V charger is going to charge your car the same since it is 240V, but as you can see this is far from the case.

There are many portable Level 1/Level 2 chargers on the market and they usually include both the 120V and 240V cord and plug. They start at $179 for a 16A model from Lectron, but if you are going to upgrade I suggest getting at least a 30A charger. These start at around $375.

Emporia Energy makes an excellent Level 2 charger that works at 40A with a 240V plug and 48A with a hardwired (to a junction box) configuration. The $499 Emporia EV Charging Station comes in a watertight outdoor enclosure with a 24-foot charging cable and while it is an excellent standalone charger, it can also tie into Emporia’s energy management system for energy savings throughout the home. The charger can also be set to charge only with solar power (in homes so equipped) or at night when utility rates are lower. The charger can be bundled with the energy management system starting at $614, and installation may qualify you for federal and state tax credits. Home battery systems, sensors and smart plugs are available as well. Learn more at