Introduction to EV Chargers

In many ways, refueling an electric vehicle is much simpler than fueling a petrol-dependant car. There is no odor or mess, decision between different fuel grades, or need to find a dedicated petrol station: all you need is a connection to the same electricity grid that powers your lights, computer, or smartphone. This page is Meo Electric’s introductory guide to the basics of electric vehicle charging.

As long as you have access to electricity, there are really only two unknowns to charging an EV: how you connect your vehicle, and how fast it will charge.

EV connector standards

J1772 Connector
A standard J1772 connector

Almost all EVs in North America charge through the same standard connection port, called SAE J1772. The only exception is Tesla, which have their own charging standard, however most Tesla drivers purchase a J1772 adapter to take advantage of the large network of J1772 infrastructure.

There are an additional set of charging standards to be aware of, specifically for DC fast charging. EV charging speeds are often divided into 3 categories: Level 1, 2, and 3 charging. Level 1 & 2 charging uses AC (alternating current) power. However the fastest charging speed, Level 3, uses DC (direct current) power. There are three common Level 3 charging standards:

EV connector standards

  • J1772 combo: the same shape as a standard J1772 adapter, with 2 addition DC fast connector pins below. Found on BMW and Chevrol EVs.
  • CHAdeMO: a Japanese standard for fast charging. Found on Nissan, Mitsubishi, and Toyota EVs. In North America, a Japanese-made EV with fast-charging capabilities will have both a J1772 port, and a CHAdeMO port.
  • Tesla combo: Every Tesla car is equipped with onboard support for fast-charging through Tesla’s standard connector. Tesla’s Supercharger network provides DC fast-charging for Tesla drivers. Tesla drivers can also take advantage of other DC fast-charging stations using a CHAdeMO adapter.

Determining charging speed

When determining how fast an EV will charge, there are two important numbers related to electrical current: volts and amps. A good analogy for the flow of electrical current is the flow of water through a pipe. In this analogy, voltage is represented by water pressure, and amperage is represented by the diameter of the pipe. Both higher water pressure, and a bigger pipe, will result in a greater amount of water flowing over the same period of time. Likewise, there are two ways to increase the flow of electricity and thus the speed with which a vehicle will charge: increase voltage, or increase amperage.

We often measure EV charging speed in kilowatts. Kilowatts can be calculated simply by multiplying voltage and amperage: 120V x 15A = 1,800 watts = 1.8 kW charging speed.

EV battery capacity is often measured in kilowatt hours (kWh), which is simply a unit of energy representing the amount of power that could be transferred at a speed of 1 kW in the time of one hour. For example, if you were charging a Nissan Leaf with a 24 kWh battery at 1.8 kW, it would take about 13 hours to fully charge from a zero charge state.

Charge speed calculator