Level 1 vs Level 2 charging at home

Every electric car can charge at home in two ways. Level 1 uses a regular household outlet. Level 2 uses a 240-volt circuit, the same kind of power that runs an electric dryer or a range. The right one for you depends on how much you drive and on what your house can supply.

Level 1: the regular outlet

Level 1 charging uses a standard 120-volt outlet and the portable cord that comes with most cars. Nothing has to be installed. The trade-off is speed: Level 1 adds only a few miles of range for each hour the car is plugged in, so a full charge of a large battery can take more than a day.

Level 1 can be enough if you drive short distances, if the car sits at home for many hours every night or if it is a plug-in hybrid with a small battery.

It also asks more of the outlet than most things you plug in. Charging pulls a steady current for hours, which is harder on an outlet than a vacuum cleaner running for ten minutes. An old or worn outlet, or a circuit shared with other appliances, can overheat or trip its breaker.

Level 2: the 240-volt circuit

Level 2 charging uses 240 volts and a wall-mounted charger, or a portable one plugged into a 240-volt receptacle. It is several times faster than Level 1. For most cars that means a full battery overnight, even after a long day of driving.

Level 2 needs its own dedicated circuit from the electrical panel, with nothing else on it. That is the part an electrician installs.

How fast Level 2 really is

Three things set the speed, and the slowest one wins:

• The circuit. Because charging runs for hours at a time, the charger is set to draw no more than 80 percent of what the circuit is rated for. A charger that delivers 40 amps sits on a 50-amp circuit, and one that delivers 48 amps sits on a 60-amp circuit.
• The charger. Each model has a maximum output, and many can be set lower to match a smaller circuit.
• The car. Every car has an onboard charger with its own limit. A car that accepts 32 amps will not charge faster on a 48-amp charger.

So the biggest charger is not always the best purchase. If your panel has limited capacity, a smaller circuit can still fill the battery overnight. For what goes into the price, see my guide on what affects the cost of a home charger.

Which one should you choose?

Think about a normal week instead of the longest trip of the year.

• Add up the miles you drive on a typical day.
• Count the hours the car is parked at home each night.
• Check whether your utility offers lower rates at night. If it does, a faster charger lets you fit all your charging into those hours.

If Level 1 puts back overnight what you use during the day, you may not need anything else. If the battery keeps falling behind, or you want to be able to leave with a full battery on short notice, Level 2 is the answer.

Fast charging stations along the highway use direct current and far more power than a house has. They are not an option for a home.

What you can safely check yourself

• Read your car’s manual for its maximum AC charging rate and for what it says about charging from a household outlet.
• For Level 1, find out what else is on the same circuit: switch the breaker off and see what stops working. The fewer things sharing it, the better.
• After the first hour of charging, touch the plug and the outlet cover. Warm is normal. Hot is not.
• Look at the outlet itself. A plug that sits loose or falls out means the outlet is worn.

When to stop and call an electrician

• The plug, the cord or the outlet gets hot, or you see browning or melting around the slots.
• The breaker trips while the car is charging.
• The only outlet near the car is too far away. Do not solve that with an extension cord.
• You want a 240-volt receptacle or a wall charger. That is new wiring from the panel and it is not a do-it-yourself job.

If you are not sure which level fits your house, send me the model of your car and a photo of your panel with the door open. See EV charger installation or ask for a free quote.