CarCharging Logo

Charging at Home

Most EV owners will want to install a dedicated 240V electrical circuit to charge their cars. This will typically give you from 20 to 30 miles of added charge per hour which is enough for a full charge overnight. It is recommended that you install a dedicated EVSE to charge your EV.

Briefly, an EVSE is a box that hangs on your wall wired to a 240V breaker in your electrical panel and has a handle that plugs into your car. All North American EVSEs and EVs use the same standard (J1772) so any EVSE will work with your car. Teslas use a proprietary charge plug, see below.

Different EVs accept different charge rates, but the industry is slowly converging on EVs accepting approximately a maximum of 32A of charge. For new installations, install an EVSE that can supply at least 32A on a 40A breaker. Even if your EV can't charge that fast (most newer ones can), you are future proofing yourself for your next EV.

Can I charge with 120V?

Some people get by with only charging using a regular household 120V receptacle. If your driving needs are modest, it is possible to keep an EV charged this way. Most EVs come with a way to charge from a 120V receptacle (see the EV Specific menu entries). Be aware that you will only be adding 3 to 5 miles of range per hour of charging. That's 48 to 80 miles of range added in a 16 hour overnight session.

Note that charging via 120V isn't as efficient as charging from a 240V source since the car draws more power during charging than when idle, meaning that a longer charging session results in more electricity being used overall.

Teslas are (a bit) different

While all Tesla cars are compatible with J1772 plugs through a small and simple adapter, they natively support a Tesla proprietary car charging plug.

So, while you can charge a Tesla with a J1772 compatible EVSE just fine, it is more convenient to use Tesla's EVSE since you don't need to use the adapter. Luckily, Tesla's EVSE (called the Wall Connector, available at the Tesla store), is priced competitively and is very capable.

Teslas are also different because they come with a very capable Mobile Connector (used to be called the Universal Mobile Connector or UMC). The Mobile Connector comes with interchangeable plug adapters allowing you to charge from household 120V receptacles all the way to 50A NEMA 14-50 240V receptacles. Click here for older Model S/X adapters, and here for Model 3/Y and newer Model S/X (year 2018 onwards).

Instead of installing a permanent EVSE, a lot of Tesla owners just install a 50A NEMA 14-50 receptacle and use their Mobile Connector to charge their car. I recommend that people not do this and to purchase the Tesla Wall Connector instead, leaving the Mobile Connector in the car's trunk. This ensures you won't forget the Mobile Connector when going on a trip, and the Wall Connector is a much more robust EVSE meant for daily charging use.

Charging in Condos

If your condo parking space does not already have a dedicated EV charging receptacle, you will have to go through a process to get one installed. Some condo associations are easy to deal with while others put up as many roadblocks as they can. Be aware that certain states have laws that require a condo association to allow you to install your own EVSE (at your own expense) with no unjustified restrictions.

EverCharge is a company that works with condo associations to install shared and non-shared EVSEs.

ChargePoint is another company that has solutions for condo charging.

DCC sells a box that can allow you to install a 240V EVSE onto a small (maybe fully loaded) electrical panel that you might find in a condo or older house. Use this instead of having to do a panel or service upgrade (which is usually impossible in a condo).

Here is a good guide on condo charging, with a specific focus on laws in Ontario, Canada, but there is lots of good information here.

Some condos and apartment dwelling EV owners will opt to charge their car at work or, if all else fails, using public chargers. Tesla owners are more apt to rely on charging outside their home on a routine basis since they have access to very high power, reliable and available Superchargers.

Charging Faults

Sometimes you will have a problem charging at home. Your car will usually notify you when it detects a charging problem. You can also tell if there is a problem by feeling the receptacle plug. It may be warm, but it shouldn't be hot to the point where it is uncomfortable to hold your hand there.

Usually a charging fault means that there is a problem with your receptacle. Most applicances do not put much of a strain on receptacles, but EVs push receptacles near their design limits, so if there is any fault in them, an EV will show it.

If you suspect a receptacle problem, the easiest and quickest thing to do is to replace the receptacle. This is a quick job for an electrician, or if you are handy, you can do it yourself. Click here for a video that shows you how to replace an old NEMA 10-30, 3 prong dryer receptacle.

Ground Fault Circuit Interrupter (GFCI)

GFCI receptacles or breakers are often found on garage and outdoor receptacles and sometimes on 240V circuits like NEMA 6-20. They trip if they detect very small currents leaking from the hot wire(s) to ground, aiming to protect humans from shocks in fault situations.

It turns out that most EVSEs actually leak a tiny bit of current to ground when they first start charging as a test to make sure the ground pin is actually connected to a useful ground. The EVSE test leaks a small enough or quick enough current such that it won't trip a properly functioning GFCI. But older and weaker GFCIs have been known to trip right at the start of charging and weak GFCIs can also trip during charging as well.

If this happens to you, replace the GFCI receptacle or breaker, and your charging problems should go away.

Note that GFCI receptacles come in two sizes: 15A or 20A. If you have a 20A breaker protecting your receptacle, then buy the 20A version. It'll be more robust and allow you to charge even faster if you have the appropriate mobile EVSE.

Copyright 2021 CarCharging.us