In many ways, buying a used electric car is a lot like buying any other used car. You’ll want to check the car’s mechanicals, check the history for being wrecked, inspect the body and interior for damage and excessive wear, etc. You don’t have to worry about an engine or exhaust system, and most EVs have a simple gearbox instead of a transmission. The big difference, of course, is the battery.
We’re in the infancy of the electric vehicle industry and things aren’t as standardized as you might like. Evaluating the battery pack varies by vehicle and most have no helpful instrumentation in that regard. Fortunately, the two best-selling all-electric vehicles do. For the Nissan LEAF® you can just look at the dash. You’ll see a cluster of digital information about the battery. The state of charge just shows how charged the battery is at the moment. The range estimate is also irrelevant, as it depends on how the car has been driven lately and can be totally misleading; what matters are the capacity bars. A new LEAF will show 12 capacity bars, two red and ten white. After losing approximately 15% of the battery capacity, the top white capacity bar disappears, each additional lost capacity bar represents 7.5%.
Nissan’s battery capacity warranty says the LEAF will keep 9 or more capacity bars for 5 years or 60,000 miles. Most LEAFs do much better than that.
Note that the capacity bars can be reset to 12. It then takes several weeks for the car to recalculate and display the battery pack’s capacity. It’s rare, but some buyers have reported being deceived by this. We recommend buying from a dealer trusted by the local LEAF owner community.
For the Tesla Model S, you’ll need to look at the dash when the car is fully charged to 100%. In the center of the speedometer will be one of several numbers. You want to see “rated miles” below the number. If it says something else, have the owner/dealer change the setting. A new Model S will show a number close to the EPA rated range for that vehicle, which varies by battery pack size and various drive options. For example, a 2015 Model S 60 has an EPA rated range of 208 miles. More examples are here.
For the most part, other electric vehicles give no indication of battery capacity, a problem for owners and used car buyers alike, which we hope will be addressed in the near future.