Charging Your Electric Vehicle at Home in Acton

April 27, 2024

Any electric car makes an ideal second vehicle for local use. Electric cars can be used intermittently or frequently. Their mileage is not hurt by short trips. If you can charge at home, it’ll be filled up when you start the day. Stopping to fill-up is a thing of the past. For example, if you have a car with a 250-mile range, you can plan to use the car within about 130 miles round-trip without worrying about charging, even while using energy to heat the cabin. You may find that you can push the range further, especially in warmer weather.

EV charger types - 5-pronged J1772 and 3-pronged NACS.
The two common types of chargers: J1772 (upper) and NACS (lower). Photo: David D. Martin

Charging Connectors:

There are two main types of charging connectors on EVs: NACS (North American Charging Standard) and J1772 (Combined Charging System without the bottom pins that are used for Fast DC charging). Through the 2024 model year, J1772 is the most common connector. Teslas use NACS, which is expected to become the standard in North America. It’s a compact connector that supports all types of charging. Most car makers are planning to standardize on NACS starting in model year 2025. Until then, there are simple adapters to convert from NACS to J1772, or visa versa.

Level 1 Chargers:

Level 1 chargers are 115V, between 12 and 16 amps. They use either J1772 or NACS plugs to connect to the car. Many cars come with a Level 1 charger. They use a normal 115V house outlet, but they charge very slowly, adding only about 4-5 miles each hour.

If you have access to a normal 115V plug where you park at home, you’ll be able to add about 50 miles overnight. If you average less than 50 miles a day, Level 1 may be all you need for local use. Note that if you park outside on the coldest nights of winter, there might not be enough energy available in a Level 1 charger to warm the battery for charging.

Kim Kastens lives in a single-family home in Acton and drives a 2012 Chevy Volt hybrid. She says “I use the Level 1 charger that came with the car, plugged into an ordinary outlet in my garage. That works fine for me, because most of my driving is local and there is usually time for me to get a full charge between trips. For longer trips, I use gasoline. When I first tried charging the car this way, it kept flipping the circuit breaker, but I switched to a different circuit and it’s been working fine ever since. Although I park my car outside, I haven’t had trouble with charging on cold nights.”

Woman inserting a charger into a Chevy Volt. The power cord snakes into the garage.
Charging from an outlet in the garage with a Level 1 charger.

Level 2 Chargers:

Level 2 chargers are 230V, between 15 and 80 amps. Some cars cannot accept a charge at the higher end of the amperage range. Those cars will just max out at their limit.

The amount of range gained each hour is roughly a few miles less than the number of amps. For example, a 30 amp charger will add about 25 miles each hour. Level 2 chargers are available with a J1772 connector or the NACS connector.

Most of the chargers that you’ll find in parking lots are Level 2 chargers with the J1772 connector. They are called Destination Chargers, because they don’t charge fast enough to use en route. They’re good when you’re going to be someplace for hours, such as at work.

A few public chargers are available, but most are part of a network. ChargePoint is the most common around here. To use them, you just wave a network card or your phone in front of the charger and plug in your car. Your credit card will be charged. Some places charge by time, ; others by kilowatt-hours. Rates vary, but it’ll usually cost less than the equivalent amount of gasoline. Some apartment complexes have networked chargers in their parking lots. Some Acton residents have found challenges to installing chargers at multi-family dwellings. That is a topic for a future Acton Exchange article.

If you want to have a Level 2 charger at home, you’ll need a 230V outlet where you park. Plus, you’ll need the Level 2 charger itself. They look like the Level 1 charger that comes with the car, but connects to a 230V outlet. Level 2 chargers work on all electric cars. Just use an adapter if the car and charger use different connectors, NACS vs. J1772.

Typically, the 230V outlet where you park at home will be a NEMA 14-50 (same as an electric range), supporting chargers up to 50A, or a NEMA 14-30 (same as an electric dryer), supporting chargers up to 30A. There are other styles of plugs, but they are less common. You can also have the charger hard-wired, but then you’ll need an electrician to make changes.

When West Acton resident Franny Osman and her husband bought a fully electric Chevrolet Bolt in 2018, they hired an electrician to install the correct service needed for a Level 2 charger and to run the wire through a small trench from the house to the driveway. They installed two chargers side-by-side, knowing that more electric vehicles were in their and their neighbors’ future. Osman designed a hinged arm for the charging connectors so they could be swung out of the way of snowplows when needed. Osman said, “It’s good to remember that the car stores much more charge in warm weather than in cold.”

Man inserting charger into a Chevy Bolt. JuiceBox Level 2 chargers are in the background.
Plugging the Level 2 charger into a Chevrolet Bolt. In the background are two JuiceBox brand Level 2 chargers and the green swinging arm that holds the connectors.  Photo: Franny Osman

You can install either a hard-wired charger or just a 230V outlet for a Level 2 charger. Hard-wired chargers are more weatherproof for outside, and networked hard-wired chargers can use off-peak rates. An outlet will allow you to change chargers in the future without calling an electrician. If your home electrical panel capacity is tight, a 20-30 amp charger is fine – 30 amps is the sweet spot. 30 amps will allow your car to charge fully overnight, while drawing less current to compete with other electrical uses at home. A 40+ amp charger is only necessary if charging time is very important.

A NEMA 14-30 outlet supports chargers up to 30A. NEMA 14-50 plug supports chargers up to 50 amps. Make sure that the plug on the charger matches the outlet where you park. If you have a NEMA 14-50 outlet and a NEMA 14-30 plug on your charger or vice versa, you can get an inexpensive adapter to convert one to another. Of course, if you have a NEMA 14-30 outlet, you must not connect a charger that draws more than 30 amps. Chargers over 50 amps must be hard-wired.

Having an electrician run wiring for a 230V outlet will cost hundreds to thousands of dollars, depending on if your panel or electric service needs to be upgraded. The Level 2 charger itself can be purchased in stores or on-line for several hundred dollars.

Your EV dealer or your electric utility may offer incentives for installing a Level 2 charger in your home. Also, your electric utility may offer a recurring rebate, if you allow them to pause your charging during periods of peak electric demand. Often, this requires a branded charger such as ChargePoint.

Off-Peak Rates:

Using a network charger at home may allow you to take advantage of cheaper electricity rates overnight. Network chargers such as ChargePoint can coordinate with your power company for lower billing of off-peak charging.

Level 3 – Fast DC charging:

In order to be used on long trips, your car must support Fast DC charging, but that’s for a future article.

Need more individualized advice?

The Town of Acton Sustainability Office in collaboration with Abode Energy Management offers Clean Energy Coaching. Residents can find more information about the program or request a coach on the Town of Acton Clean Energy Initiatives web page.

David D. Martin is one of Acton’s volunteer Clean Energy Coaches.


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