Electric Vehicle Chargers Information
Electric vehicle (EV) charging stations charge electric vehicles. Charging stations are designed either for home or public use and may have different charging rates. There are three basic charger types: Level 1 (120V), Level 2 (240V), and DC fast charging (500V).
Level 1 charging (120V AC) relies on 1 phase AC power. This charging type uses existing power outlets and extension cords. No additional charging unit is required. This charging technique can take over 20 hours to charge a vehicle. It usually provides 10 amps at 1200W.
Level 2 charging (240V AC) relies on 2 phase AC power. These charging units use two phase power and are available with varying charging speeds up to 19.2 kilowatts and can charge a vehicle in as little as a few hours. Free public chargers are usually level 2 types.
DC fast charging (500V DC at 125 Amps) is the fastest charging type and produces 62.5 Kilowatts of charging power. It is also known as “CHAdeMO” or “CHArge de Move.” These are for commercial and public access installations. The vehicle is connected to the main power grid through an external charger. The system is capable of charging vehicles in 10-15 minutes. These heavy duty chargers are usually run off 3 phase AC power, which they rectify into DC current.
All electric vehicles come with built-in chargers that can be plugged into any standard 120 VAC outlets (level 1 charging). But this is a very slow way to charge an EV car. It may take a day to get a full charge, depending on the size of the battery and the power rating of the built-in charger. Cars can be charged superfast using high voltages. The charging rate is proportional to the difference between the voltage of the battery and the higher voltage of the charger. The higher the charger voltage, the greater the current and the faster energy is transferred to the battery being charged. Higher voltages mean shorter charging time. Efficiency and battery life are reduced when higher voltages are applied, however. The slowest charge, sometimes known as a trickle charge, is the most efficient and battery-friendly way to charge a car’s battery. This is the recommended way to regenerate an old automotive battery. But having to wait almost a day is rarely practical. Also, when a battery reaches around 80% of charge, the charging rate decreases since its voltage and internal resistance gets higher. So sometimes it is best to not fully charge the battery if a motorist doesn’t need the extra range and is short on time.
As of 2016 the US government is offering 30% tax credit incentives for EV charging stations installations. State and other foreign government are also incentivizing these devices.