EV Charging Explained

Electric Vehicle Charging Explained:


Most new Electric Car Manufactures in North America have adopted a Vehicle to Charging Protocol with a universal connector known as SAE J1772. (Tesla being one that has not). Yes, all Charging Stations and Vehicles coming out today use the universal standard in the USA.

Electric Vehicles (EVs) have three different methods of charging the vehicle:

Level 1: 120V AC Charging – This is typically a cord set that will plug into a standard wall outlet and comes with the EV/Hybrid Plug-In Vehicle.

Level 2: 208-240VAC Charging – This s typically an additional accessory that requires an electrician to install a 20A – 40A circuit in your home or at a commercial location.

Level 3: DC Quick Charging – This type of Charger is only available in commercial/industrial locations with 480VAC 3-Phase power.

Level 1 and Level 2 Charging use the same connector and same charge port on the vehicle. Level 3 DC Quick Charging uses a different charge port on the Electric Vehicle.

Everyone asks: How long does it take to fully Charge my Electric Vehicle?

Well…That depends on a lot of things. How big is your battery?, what is the State of Charge of the Battery?, how many miles have you driven?, how many miles do you plan on driving?, and what type of Charger do you have? There are a lot of factors that play into how fast can I charge.

So let me Explain:

The Electric Vehicle (EV), has an onboard charger. This is the maximum rate that your Electric Vehicle can charge at on Level 1 and Level 2 Charging. Very few of the current EVs/PHEVs have the Level 3 Charge port (explained later). The Onboard Charger is the speed that the electric vehicle can charge at, EVs on the market today have On-board chargers ranging from 3.3kW to 10.2 kW.

So 10.2 kW is faster…?

Not Necessarily:

The vehicle is limited by the output of the Electric Vehicle Charging Station that you connect. For Example, a Level 1 cord set on a standard outlet will have an output of 1.2kw. So that 10.2 kW Toyota Rav4 can only charge at 1.2 kW when using the Level 1 corset.

If you “upgrade” to Level 2 Charging Station, you can charge at a faster rate, a 30A EV Charging Station can recharge at 7.2kW….6 times faster than the 120V Level 1 Cordset. As a rule of thumb, you will want a Level 2 if you plan on driving more in a day than you can recharge in an 8 hr period.

More Details:

What is SAE J1772 Connector and Standard?

SAEJ1772 = Society of Automotive Engineers standard for Electric Vehicle Charging. Most all automotive manufactures operating the the United States have adopted this protocol to have a universal charging port and connector for the charging infrastructure.. This standard is vital to the long term prospects and investment into Charging Infrastructure. No one wants to invest in a concept that would only appeal to a select few. Imagine a world of different sized gas pumps, well I guess there is Diesel….

SAE J1772 also outlines the Vehicle to Charging Station communication. When the connector is inserted into the vehicle the Vehicle responds with a similar handshake, the Charging Station tells the Vehicle “Hey I’m can output 30Amps, you want it?”, the Vehicle then responds with “Sure”, “Yes, but 15A”, “No, I’m Full”. The Vehicle will accept as many Amps as the Onboard Charger will take.

The Charging Station and Vehicle communicate through a Pilot signal through the connector, when engaged the voltage drops through a series of Steps saying “I’m Connected”, “Charging”, “I’m Connected”. The Charging Station never actually knows where the Vehicle is at in the State of Charge or how full the battery is. The Vehicle has most of the “Smarts” onboard with a Battery Management System that controls and monitors the battery while charging. The Vehicle simply stops requesting power and the Charging Station opens the switch.

For more information on the specifics of SAE J1772 I recommend checking out the standard on their website:

The Charing Station is really just a smart safety switch. You can plug the Connector in the rain, snow, lick it and you shouldn’t be shocked. Charging Stations are also Subject to a whole slew of safety rules and standards from both Underwriting Safety Laboratories to the National Electric Code: Article 625.

The Vehicle has the actual charger onboard, the Level 1 and Level 2 Charging Stations simply deliver AC power to vehicle to charge the battery when requested by the Vehicle aka when It’s safe to do so. The Charging Stations are necessary because of the long, constant loads being applied , and the indoor/outdoor charging elements. The Charging Stations have many more safety features than a simple extension cord, such as GFCI protection, breakaway, auto shutoff, and insulated pins from exposure.

Level 3 DC Quick Charign is a whole bother animal to tackle.

For More information I recommend the following link:

SOC – State of Charge, basically how full your battery is.

What type of Charging is right for you?

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