How electric cars work

When you plug your EV into a power source

The car draws electricity from and stores it in a battery pack. The pack has a limit to how much electricity it can hold, just like a tank can only hold so many gallons. In an EV, this limit is expressed in kilowatt hours, or kWh. While there is probably a small percentage of the battery’s full capacity that the engineers have reserved for technical reasons relating to battery life and safety, most batteries are rated for their useable kWh. In used and new EVs, you’re going to see battery capacities that range from the mid-teens (16 kWh) in the Mitsubishi i-MiEV all the way up to 100 kWH in the most expensive Teslas. Most of the common used EVs will have around 20- or 30-kWh packs, like the various first-gen Nissan Leafs (depending on model year trim level), while the newer models (Chevy Bolt EV or the second-gen Leaf) have packs with 40-60 kWh. Depending on how efficient an EV is, it will go a different number of miles with each kWH in the pack, but the general, obvious rule is that bigger batteries allow a car to go farther, but also cost more.

It’s smart to buy the EV that has enough range to cover your average daily drive and not that much more, especially if public charging is an option where you live.

On the road

The battery feeds energy to the electric motor, a compact and powerful — and quiet — tool that replaces the engine in a gas or diesel car. Almost all passenger EVs use direct drive to move the wheels, so there’s no need for a transmission.

How long your EV has to be connected to a plug to refill its battery

This depends on many factors. The good news is that all modern EVs are able to accept at least 240-volt, Level 2 charging speeds, which adds about 25 miles of range per hour of charging to your battery pack. Each MYEV listing will specify if that EV can accept faster charging technologies, like CHAdeMO or SAE Combo, which can fill up to 80 percent of a battery’s total capacity in just 20-30 minutes. This is somewhat comparable to refiling your car at a standard gas station, and the best-known examples of these DC Fast Chargers are Tesla Superchargers, which can only be used by Tesla vehicles but are widely available across the U.S., making cross-country travel a unique selling feature for these cars.

Another thing to consider is if a used EV has an aftermarket warranty

In fact, the powertrain warranty for more EVs lasts longer than the general warranty does. For example, the basic warranty for the 2018 Nissan Leaf lasts for three years or 36,000 miles. The powertrain, though, is covered for five years or 60,000 miles. This should give buyers the confidence they need to try the new technology, but it’s not a big issue for the automakers since the evidence over time suggests that most EV battery packs are very reliable.