Electric energy is measured in kilowatt-hours (kWh). The "mileage" for EVs (and PHEVs) ranges from 3-4 miles per kWh of electricity. When an EV is charged, it is like "filling the tank" with electricity. The "tank" is the battery, which stores the electric energy until it is needed to run the electric motor.
Pure EVs, such as Teslas, the Hundai IONIQ 5 etc. contain large batteries and can go 150-350 miles on a single charge. However as mentioned below, EVs should not routinely use their entire range, and so should be recharged every 90-200 miles depending on the model.
Tesla recommends that for maximum battery life, the car should be plugged in every night regardless of charge level.
• EVs must be recharged frequently to avoid damage
Lithium-Nickel EV batteries are permanently damaged when run all the way down or recharged to 100%. The damage is small but cumulative, and if repeated frequently the battery may wear out prematurely. All batteries loose storage capacity over time. "Wear-out" means capacity has declined to the point that the vehicle's range is severely compromised.
Manufacturers say to routinely charge to at most 80%, and recharge before dropping below 20%. It is perfectly okay to exceed these limits occasionally, just not on a regular basis.
Lithium-Iron batteries are a newer technology and until recently it was thought that they could be routinely charged to 100% without damage. However a recent study indicates otherwise.
Plug-in hybrids also allow charging their battery at home using AC power. They can run using only battery power for short distances, about 25 miles with the latest PHEVs (as of 2025, from 7 to 44 depending on the car). Plug-in hybrids have much larger batteries than non-plug-in hybrids (though still small compared to an EV), and usually more powerful electric motors.
This is good for people who usually make only short trips, provided they actually plug in after every trip.
• Recharging PHEVs after every drive is essential to avoid negating the environmental benefit of the plug-in feature!
Once the gas engine starts it will recharge the battery, and all else being equal the car will get worse mileage than a non-plugin hybrid because of the extra weight of the larger battery and motor.
Electricity costs half as much in off-peak hours on a Time Of Use (TOU) rate plan, so EV owners usually charge at night (most EVs have a way to tell the car wait until after midnight to begin charging). In Northern Calif. served by PG&E, off-peak hours are midnight to 3 pm.
Level 1 charging uses 120 volts AC from an ordinary household outlet. This is too slow for EVs but adequate for PHEVs.
Level 2 charging uses 240v AC power, supplied via a 240-volt plug or hard-wired. A 30-amp circuit is adequate and a 40-amp circuit is "premium".
Level 3 refers to super-fast charging with high-voltage DC, used only at public chargers for long-distance travellers. They require expensive equipment and an industrial-strength utility connection.
Until mid-2024 "Net Energy Metering" was available... you got full credit for supplying excess solar energy to the grid, offsetting the cost of energy pulled from the grid at night. If your solar system is covered by the old "NEM-1" or "NEM-2" regimes then you're all set: Switch to a Time-Of-Use rate plan and charge after midnight.
Unfortunately Net Energy Metering was gutted due to heavy lobbying by PG&E, and new solar installations receive only a small credit for energy supplied to the grid.
All portable chargers work with 120-volt outlets, and most also provide adaptors to plug into various 240-volt receptacles like those used at RV hookups or clothes-dryer outlets.
Portable chargers have moderate rain resistance (e.g. IP44) and are usually considered safe in the rain if plugged into a weatherproof outlet and put back into the car or brought inside when not in use.
Permanent chargers are mounted on a wall or pedestal. You just take the cord down from it's holder and plug it into your car.
Some permanent chargers are impervious to weather and need no protection, while others should be installed only in a garage or carport. Chargers can be hard-wired or plug into a 240-volt outlet (rain-protected if outdoors).
240-volt outlet types: Many people keep the "portable" charger which came with their car permanently in their garage, plugged into a suitable 240-volt outlet. Wall-mounted chargers can also plug into a 240-volt outlet or be hard-wired directly to the branch circuit.
The most suitable outlet for supplying EV chargers is a NEMA 6-50; NEMA 6-30 can also be used for a 30-amp circuit. These provide only 240 volts, exactly what EV chargers need. NEMA 14-50 receptacles are often installed by contractors in new or remodelled garages for EV chargers, but are unnecessarily expensive because they require an additional wire (Neutral) to supply 120v power as well as 240 volts. EV chargers will not use this so the additional cost is wasted.
Tesla's plug (NACS) has many technical advantages over the J1772, and almost every auto manufacturer now uses NACS in the United States.
As mentioned above, J1772-equipped home chargers can easily charge Teslas and other NACS-equipped cars using an adaptor; the reverse is also possible but NACS-to-J1772 adapters are somewhat larger and less convenient to use.
Tesla and others sell "combination" chargers with both J1772 and NACS plugs. This may be a good choice for apartments or businesses likely to be used by the public.
Note: NACS also works for DC fast charging on the road but J1772 by itself is only for slow charging at home or a hotel (more on that below).
A
Grizzl-E Duo charger has two charging cords (NACS, J1772, or one of each),
sharing the power from a single supply circuit.
Up to four
Tesla wall chargers can similarly share a single 240-volt branch circuit.
If your home's electric panel can't handle even one dedicated circuit, there are sharing devices which allow an electric clothes-dryer outlet to be shared between the dryer and an EV charger (basically it disconnects the charger whenever the clothes dryer is in use).
The Tesla Supercharger network is by far the largest and best. There are thousands of stations with well-maintained equipment. Other networks (EVgo, ElectrifyAmerica, etc.) are now catching up but have fewer chargers and a history of poor reliability.
Fortunately non-Tesla cars can charge at many (but not all) Superchargers, although the cost of charging is somewhat higher, depending on what was negotiated between Tesla and the other manufacturer.
The NACS plug used by Tesla (and others) works for DC charging;
older non-Teslas require a bulky "CCS1" plug for fast charging.
Many Tesla Superchargers offer both kinds of plugs, although not all
non-Tesla vehicles work with Superchargers even if they have the right plug.
If you are considering a used non-Tesla EV,
be sure it is approved for use on the Tesla Supercharger network
and that the car's software is compatible.
