One of the most important considerations when choosing an electric vehicle is its battery. How big should it be? How fast will it charge? How long will it last between charges? The answers to these questions can be overwhelming—full of formulas, abbreviations, and unfamiliar terminology. Let’s cut through the confusion to get you up to speed on the essentials.

Note: We’re using Canadian units of measurement. To convert to U.S. measurements, consult Natural Resources Canada’s 2022 Fuel Consumption Guide.

Inside the Battery

An EV battery is more accurately described as a lithium-ion battery pack. The pack is made up of cells that provide an electrical current as they discharge, powering the vehicle. Lithium-ion batteries can store a lot of energy relative to their size and weight, which makes them ideal for portable devices, such as laptops, cellphones, and EVs.

Size Matters

Larger battery packs contain more cells and deliver more power. They also cost more, and the extra size and weight add to the vehicle’s overall size and price. The Hummer EV Pickup’s battery weighs an astounding 1326 kg—more than some EVs in their entirety.

Energy Capacity

The fuel capacity of a gasoline vehicle is measured by the number of litres that can be stored inside its tank. An EV battery’s energy capacity is measured in kilowatt-hours (kWh)—the amount of power it can provide for an hour of continuous use. For example, the 2022 Tesla Model 3 RWD has a battery capacity of about 60-kWh, which means it can discharge up to 60 kilowatts over an hour—in tests, anyway.

In the real world, batteries usually aren’t pushed to their maximum output. For a more practical sense of a battery’s capacity, imagine using the Tesla 3’s battery to power a dryer. If we assume the average load of laundry uses roughly 2 kWh, the 60-kWh battery could run the dryer for thirty straight hours.

Fuel Consumption

To determine an EV’s fuel consumption—the amount of energy used while driving it—the battery’s capacity is associated with a unit of distance. In Canada, the fuel consumption rating is an estimate of the amount of kWh used to drive 100 kilometres. The fewer kWh required, the better the rating.

Running errands in town requires less energy than speeding down the highway, which is reflected in their respective ratings. The Tesla Model 3 RWD, for example, has a rating of 15.2 kWh/100 km for city driving and 16.6 kWh/100 km for highway driving.

Electricity vs. Gas

For many drivers, an EV’s fuel consumption isn’t meaningful until it’s compared to the amount of gasoline needed to drive the same distance. This is expressed as the gasoline litre equivalent (Le) per 100 kilometres (km).

The Tesla Model 3 RWD has a rating of 1.8 Le/100 km for city and highway driving combined. To put this in real terms, it uses the equivalent of 1.8 litres of gasoline to travel 100 kilometres. For comparison, a gas-powered car may be considered fuel efficient if it uses 8 litres or less of gasoline per 100 km.

Driving Range

When you’re on the road, what matters most is how far you can go before you need a charge. The distance you can travel on a full battery is known as the EV’s “driving range.” The petite 32.6-kWh battery of the Mini Cooper SE 3 has a range of just 183 km—modest by today’s standards, but the median driving range only five years ago. With its 131-kWh battery, the Ford F-150 Lightning Extended Range can take you 515 km.

EV driving ranges have greatly expanded across the power spectrum over the past two decades, the median rising from 109 km in 2011 to 377 km in 2021.

As a battery ages, its driving range will begin to shrink, necessitating more frequent charging. Battery drainage can also be accelerated by additional weight in the vehicle, such as a full load of passengers, driving at higher speeds, and temperature extremes. Cold weather is particularly hard on battery capacity, temporarily dropping the driving range by as much as 20%.

Charging Speed

Extreme temperatures have another impact on your battery: slowing down charging times. The charging time can also be increased by making demands on the battery during charging, such as running the air conditioner, and the size of the battery. The biggest determiner of charging times is the charging level—the amount of voltage and the speed at which it’s delivered to the battery.

Level 1 charging uses a standard 120-volt outlet. The slowest option, it adds between 5 and 8 kms of driving range per hour. At that rate, the Tesla Model 3 RWD can take a couple of days to return to its full driving range of 240 kms.

A Level 2 charging station, such as the Hypercharge JNT-EVC10, replenishes the driving range by 20 to 128 kms per hour. Plug in the Tesla Model 3 RWD at bedtime, and it will be charged when you get up eight hours later.

Level 3 charging stations—also known as DC Fast Chargers—add 5 to 20 kilometers of range per minute. After as little as 50 minutes at a Hypercharge DC Fast Charging Station, the Tesla Model 3 RWD will be good to go.

Maximizing Lifespan

Most EVs vehicles come with a battery warranty of at least eight years or 160,000 kms. Many experts believe the best way to maximize a battery’s longevity is to avoid draining it completely or charging all the way up to 100%. The demands of charging from low to full are thought to stress the battery and potentially shorten its lifespan.

Recommended ranges vary, but most fall between 30-80%. Whenever feasible, keep the battery level above 30% and only charge to 80%.

Electricity vs. Gas

Ultimately, your choice of electric vehicle will be guided by your taste, budget, driving habits, and access to EV charging stations. For more information on buying an EV, visit the web sites of Natural Resources Canada and the United States Environmental Protection Agency.