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Round Up: EV Charging at Home

Most EV charging happens at home or at work, so it is important to have a good charger.

While it is crucial for the practicality of EVs that we build out a comprehensive network of public DC fast chargers that can refill our electric cars' batteries on the road, the Department of Energy estimates that 80 percent of EV charging happens at home.

That's because it is not only more convenient, but it is critical to the energy cost savings promised by EVs. Residential electrical rates vary by location, but average 13 cents per kWh, according to the DOE. That equates to a cost of $4.29 to add 33 kWh to a car's battery, for example. By comparison, power from the Electrify America charging network costs $0.43/kWh for non-members and $0.31/kWh for members using the company's DC fast chargers for gas station-like refills on the go. So that same 33 kWh costs $14.19 for non-members and $10.23 for members.

Worth it, if your car needs a boost. But for daily charging, the price difference adds up, to say nothing of the time spent at the DC fast chargers. Plus, carmakers recommend against using fast charging habitually, because blasting electrons into the battery pack regularly will shorten its life compared to the slower trickle on a Level 2 home charger.

This makes buying a proper Level 2 240-volt home charger a necessary step because using the included emergency 120-volt plug to charge modern EVs with large battery packs literally takes days. When considering buying a home charging station, the factors to consider are the power service available on your breaker box and the power level the charging station can deliver to the car as a result. Most Level 2 chargers can be configured to plug into common NEMA 6-20, 6-50, or 14-50 240-volt plugs, which are typically used to connect electric clothes dryers or to power recreational vehicles. If a plug like this is located near where the car parks, you're in business.

If not, then it is a matter of having an electrician route a circuit from your home's breaker box to the garage or driveway. Then they can either hard-wire the charging station to the circuit or install one of the aforementioned outlets in the circuit for the charging station to plug into. That's the route I chose, leaving me the ability to plug in a 240-volt heater or air compressor for working in the garage.

Level 2 home charging stations deliver 80 percent of the available power to the car, so if you connect to an existing 40-amp circuit for your dryer, then your charger will provide the car with 32 amps (7.7 kW). A 50-amp circuit can provide a maximum of 40 amps (9.6 kW). If you have to have a circuit added to your breaker box, as I did, it makes sense to specify a 60-amp circuit so that you can choose a charging station that will deliver 48 amps (11.5 kW) to the car for the quickest possible charging.

The Tesla Model S and upcoming Ford F-150 Lightning have onboard charging equipment that can take 80 amps of power from a 240-volt Level 2 home charger, so if you have, or will have, one of those cars, then you'll need a 100-amp circuit wired installed in your house to power the Tesla charger or the 80-amp Charge Station Pro charging station that Ford will provide with Lightnings equipped with the optional long-range battery.

The rest of us have a variety of home charging stations to consider, so we've rounded up our favorites for you to consider. Look at the price and power delivery of each, along with the type of connection it needs to your house to decide which is best for you.

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