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Welcome to EV101: Electric Vehicle Charging Basics

Whether you own an EV, or you’re EV-curious, this page will answer all your electric vehicle related questions. We’ll cover a range of topics, from the basics — What is an electric vehicle? — to the nitty-gritty variables that affect your charging speeds. Scroll at your leisure! Your curiosity is welcome.

What is an Electric Vehicle

There are actually three types of electric vehicles. The type most people associate with “EVs,” is called a “Battery Electric Vehicle” — or “BEV.” However, there are also “Hybrid Electric Vehicles” and “Plug-in Electric Vehicles,” which we’ll discuss below.

4 Ways Charging Your EV is Different from Filling Up Your Car

The Process

The Process

Charging your EV is a lot like… charging your phone. Yes! Just like how people have different habits for charging their phones, EV drivers have different habits for charging their vehicles. Some people charge their phones at night while they sleep. Some charge at work at their desk. And others take advantage of chargers everywhere – in their car, at home, at the airport — wherever they can. So, the good news is that there are several options for how to charge your EV, just like there are for charging your phone.

Time

As of now, charging an electric vehicle from near empty to full takes more time than refilling a gasoline powered car. However, that time difference is shrinking. The EV world is versatile – and evolving. At first, the majority of people with EVs charged at home or at work over a period of several hours. Now, as thousands of fast chargers are deployed across the country, EV drivers have the option to “charge on-the-go” — as they shop for groceries, pick up a prescription, or grab a coffee — all in about 15-45 minutes.

EVs are better for the environment

EVs are better for the environment

The “end of oil” is closer than people think. Fossil fuels – including gasoline – are not permanent resources. And fossil fuel consumption produces smog, greenhouse gases, and other pollutants harmful to human health.

All battery-electric vehicles (BEVs) produce zero local emissions. And because PHEVs and HEVs are more efficient than gasoline-only powered vehicles, they produce much less tailpipe emissions, even when running only on gasoline.

There’s a common misconception that the production of electric vehicles — and the energy electricity generated to charge them — creates as much harmful pollutants as gas powered vehicles. That’s simply not true. Electric vehicle emissions are lower. And the grids that power them continue to increase their sourcing from renewable energies, electric vehicles will continue to get cleaner. On our end, EVgo powers all of our chargers with 100% renewable electricity from wind and solar.

NOTE: The Union of Concerned Scientists has an excellent visual graph to show the estimated emissions for various areas across the US – some with over 100MPGe!

Price

Price

Charging an electric vehicle costs less money than filling up a gasoline car (on average, about 35% less). The price of gasoline depends on several factors – the cost of crude oil, taxes, and world supply & demand. The price of electricity depends primarily on how many other people are using electricity. When a lot of people are using electricity, it adds strain to the grid. And this strain increases the cost of a charge. Because the electric vehicle and charging industries are evolving simultaneously, new innovations are being created to make charging faster and less expensive.

If you’re interested in learning more, check out this calculator from the US Department of Energy to see the long-term differences in cost between an EV and a gasoline-powered car:

4 Types of Connectors

When we travel to different countries, sometimes the outlet types are different. Electric vehicles are a lot like that. Because so many manufacturers around the world design EVs, they install different connector compatibilities in their vehicles. Thankfully, EVgo is compatible with nearly all of them. But it’s still important to know which “connector” is inside your EV to charge correctly.

EV Adapters

Adapters are devices that enables charging with one standard to another. Although there are several standards existing in the industry, there are few adapters in the market. The use of adapters is not recommended because adaptors add an additional part in the electric connection between EV and Electric Vehicle Supply Equipment (EVSE), which increases the probability of faults and affects the functional safety.

Approved adapters

There are three adapter types that are tested and validated. One is the Level 2 AC adapter that can be used for L2 J1772. The second is the CCS1 to Tesla adapter. The third is the CHAdeMO to Tesla adapter. Any Tesla adapters not made by Tesla are not approved for use by EVgo and can cause damage to the EVSE or vehicle.

Common failures

A common mistake is to mis-apply the Tesla AC adapter to the DC charging connector. When it is forced into a DC CCS1 plug it won't enable the charge to Tesla, and causes damage to the DC connector.

How Long Does It Take to Charge Your Electric Vehicle?

Most non-electric vehicle drivers think charging takes forever. However, electricity is everywhere, and some drivers will do the bulk of their charging at home or at work, where their car is able to "fill up" while sitting all day or all night. Also, most non-EV drivers are not aware of DC fast charging — where drivers can now typically charge in 15-45 minutes. And when you find an EVgo charger that aligns with your grocery shopping or trip to the park, it only takes a minute or two for you to plug in and tap on the app to start your session, and then the car and the charger do the work while you go run your errand for those 15-45 minutes!

Fast Charge Your EV in 3 Easy Steps

Plug In
1

Plug In

Connect to your charging port.

Tap to Start Your Charge
2

Tap to Start Your Charge

By EVgo app, RFID or credit card.

Charge Up and Go
3

Charge Up and Go

Your next destination awaits.

EV Chargers Available in EVgo's Network

EVgo has a multitude of chargers to choose from. Our “bread and butter” is DC Fast Charging, and we currently have over 950 fast charging stations across the country. And because of our “Partner Roaming” capabilities, a membership with EVgo gives you access to thousands of fast chargers across the country!

DC Fast Charging

Most Battery Electric Vehicles (BEVs) are capable of fast charging. And our fast chargers have power levels from 50 kW all the way to 350 kW. The speed at which vehicles charge is usually decided by the vehicle’s Battery Management System (or BMS — it’s sort of like the vehicle’s “brain”).

Click here to see a map of all our fast chargers and find one that’s right for your vehicle.

Level 2 Chargers

All Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) are capable of AC Level 2 charging. Because AC Level 2 charging is done at a slower rate, it’s best for people who don’t mind waiting a few hours for their cars to recharge. Many workplaces and homes are equipped with AC Level 2 chargers, and EVgo has a network of public AC Level 2 stations available as well.

Click here to see a map of all our AC Level 2 chargers and find one that’s nearby.

NOTE: DC fast charging is best for charging vehicles “up to 80% full.” Afterwards, the charging rate slows down, and it’s generally a better use of time to switch to an AC Level 2 charger.

EV Charging Terms Explained

It’s helpful to think of charging an electric vehicle like water flowing through a pipe.

What Affects Charging Speed?

Your vehicle

There are a lot of variables that affect each vehicle’s charging speed. When a battery is more depleted, the charging speed is typically faster. However, batteries don’t like to charge quickly when they’re too hot or too cold, so charging may be slower in extreme temperatures.

Different vehicle manufacturers design different batteries. And because the battery is usually the single most expensive “thing” inside a vehicle, it’s in everyone’s best interest to maximize the battery’s longevity, health, and safety. As a result, when a vehicle charges, the vehicle decides the power it draws from the charger in a way that maximizes longevity.

The charging system

Different electric vehicles have different capacities for charging speeds; charging stations also have different capacities, and the maximum rate of your charging session is determined by whichever is lower, the capability of the car or the charger. For example, a 50 kW capable EV would not charge any faster at a 350 kW station. Also, it is worth noting that higher capable vehicles can charge at lower capable stations, they are just limited to what the station can provide.

Outside temperature

Electric vehicle batteries don't like to be too hot or too cold. The charging of a battery generates heat (check your mobile phone when its charging), and the battery management system will protect a battery from overheating, so when the battery gets too hot the battery management system will slow down charging (and if the ambient temperature is high or you've been driving your EV for a long time then this might happen earlier as the battery temperature is already elevated).

How Does the Vehicle Decide Your Charging Rate?

The vehicle’s Battery Management System (BMS — or “brain”) considers all of the factors explained above in order to maximize the longevity of the battery. Is the battery hot right now? Is it cold outside? Is the battery old and deteriorated? How full is the battery? Given all of this information, the vehicle tells the charger the voltage and current it can accept - the product of which determines the charge rate.

When the vehicle starts charging, it may reach (or get close to) the maximum charging rate (i.e. 50 kW). But as the charge continues — and the battery gets hotter and its cells start to fill — the vehicle will slow the charging rate to reduce the strain on the battery. When the battery is about 80% full, the charge rate can slow rapidly, as shown in the example below:

Why Does My Charging Speed Slow Down as I Charge?

To answer that question, we first have to understand the vehicle’s battery. When most people imagine a car battery, they might imagine one big block sitting inside the car. In reality, inside a “battery pack” are hundreds — and often thousands — of smaller “battery cells.” (The Tesla Model S has up to 7,104 battery cells!) As a result, when a battery charges, those thousands of cells are actually what’s being charged.

A helpful analogy might be to imagine sitting in a movie theater. When the theater is empty, it’s easy to find a seat right away. But as the theater fills up, we have to take a few moments to find a seat — and climb over people (without knocking over their popcorn). That’s what happens with battery cells at the molecular level. When the battery cells are nearly empty, it’s easy to “find a seat” to charge. But as the battery cells fill up, it takes more time to find (and navigate) the empty cells. Generally, above 80% full is when it’s hardest for electrons to find a seat in your battery’s movie theater.

NOTE: Your charging speed will slow down throughout the course of your charge. And every vehicle decides that “slow down rate” differently. Every manufacturer determines this in order to keep your vehicle’s battery healthy and increase longevity.

Why Does My Charging Speed Slow Down as I Charge?

To answer that question, we first have to understand the vehicle’s battery. When most people imagine a car battery, they might imagine one big block sitting inside the car. In reality, inside a “battery pack” are hundreds — and often thousands — of smaller “battery cells.” (The Tesla Model S has up to 7,104 battery cells!) As a result, when a battery charges, those thousands of cells are actually what’s being charged.

A helpful analogy might be to imagine sitting in a movie theater. When the theater is empty, it’s easy to find a seat right away. But as the theater fills up, we have to take a few moments to find a seat — and climb over people (without knocking over their popcorn). That’s what happens with battery cells at the molecular level. When the battery cells are nearly empty, it’s easy to “find a seat” to charge. But as the battery cells fill up, it takes more time to find (and navigate) the empty cells. Generally, above 80% full is when it’s hardest for electrons to find a seat in your battery’s movie theater.

NOTE: Your charging speed will slow down throughout the course of your charge. And every vehicle decides that “slow down rate” differently. Every manufacturer determines this in order to keep your vehicle’s battery healthy and increase longevity.

Why Am I Not Getting the Maximum Charge Rate on My Car’s Nameplate?

There are several reasons for this. When a car advertises a maximum charging rate of 50 kW, that doesn’t mean it can consistently charge at that rate.

When a vehicle connects to a charger, a conversation takes place between the charger and the vehicle — and it’s dominated by the vehicle. The charger tells the vehicle both the voltage and current rates it can accept, and the charger provides only what the vehicle can accommodate. As a result, the vehicle manages its battery to provide the longest useful life by not overcharging it. Here are some examples of things that affect your charging speed: