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 (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 make 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, supplied 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 fast charging with high-voltage DC, used only at public chargers; requires 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 these chargers work with 120-volt outlets, and many (e.g. Teslas) provide adaptors to plug into various 240-volt receptacles such as 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 and are the most convenient option. You just take the cord down from it's holder and plug it into your car.
Some permanent chargers are rated for exposed outdoor installation, while others should only be installed 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: The most suitable and cost-efficient receptacle for EV chargers is a NEMA 6-50 (NEMA 6-30 can also be used for a 30-amp circuit). These provide only 240 volts (plus ground), exactly what EV chargers need.
Often NEMA 14-50 receptacles are installed in new construction. However these outlets are unnecessarily expensive because they include an additional wire (Neutral) to supply 120v power as well as 240 volts. EV chargers will not connect to this extra wire, so the additional cost is wasted. Most chargers can be ordered with a NEMA 6-50 plug.
Tesla's plug has many technical advantages over the J1772, and recently almost every auto manufacturer announced that they will switch to the Tesla plug (re-christened "NACS") over the next few years. New EVs are not expected to accept J1772 chargers without an adaptor.
While J1772-equipped chargers can charge Teslas using a simple adaptor, the reverse is only recently true because Tesla/NACS-to-J1772 adapters (for Level 2 home charging) have only recently become available.
Tesla now sells a residential charger which has both J1772 and NACS plugs. This might be the best choice for new wall-mounted chargers available to the public.
(This is https://abhweb.org/jima/ev_charging.php)
