Buying a used electric car can feel like a leap of faith — leaping right into the world of electrons, that is. While electric vehicle powertrains don’t require the kind of maintenance you have come to expect from a gasoline or diesel engine, there is a lot to know about their batteries.
Like smartphones, laptop computers, or countless other modern devices that use advanced battery packs, the batteries in electric cars need special care. Battery packs rarely fail, but they do degrade over time. That means they won’t deliver the driving range they did when they were brand new. Replacing an EV battery pack isn’t as labor-intensive as fitting a new engine, but it is a costly endeavor best left to professionals.
Buying a used car of any sort always means guessing about how its previous owner kept it up, but the good news is that EVs can tell us more of their story.
What to Learn About Batteries in Used EVs
Below, we will cover some essential realities you’ll want to know about battery packs in used electric vehicles. Use the jump links to skip ahead.
- What the EV can tell you
- What the dealer or technician can reveal
- How to properly charge the battery going forward
- What kind of charger to have at home
- Which apps to use when charging
- What to expect from a used car battery warranty.
1. How Much Battery Life is Left? The EV Tells You.
Electric vehicles are intelligent machines. Their various computers can tell you a lot about their battery life. For instance, how the previous driver behaved and how much life remains in their battery packs. Tesla models, for instance, offer excellent data regarding battery health.
The easiest way to determine this information is to charge an EV up to 100% and see what the car’s computer says. If the car was rated for 150 miles of range when new, but the power gauge estimates only a 100-mile range on a full charge, simple math tells you that its battery is down to about two-thirds of its original life.
If only it were that simple. While you can use an old laptop with a nearly dead battery simply by keeping it plugged in all the time, you clearly cannot make much use out of an EV with just a mile or two of range left in its battery pack.
There’s no way to fix a battery pack short of replacing it, which can cost upward of $10,000 for many newer cars with higher-capacity battery packs.
That said, an EV with limited life left may make sense for some users. If your commute is only a couple of miles round trip, you may find that an inexpensive EV with a 30-mile range would work just fine. On the other hand, selling such an EV may be tricky, as you would need to find a buyer with a very short commute.
2. Need to Know More About Battery Health? Ask a Pro.
Using the car’s built-in battery life estimator is a good starting point, but dealerships or electric car specialists at independent shops can give you even more information. They’ll plug the EV into a computer equipped with special software that can provide a detailed look into the battery’s health.
You may not think you need a pre-purchase inspection on a used EV, given the relatively low number of potential problem areas. However, anyone concerned with battery life — even on a newer EV — should consider a third-party inspection.
3. How to Properly Charge an EV Battery
The more we learn about the lithium-ion battery packs found in modern electric cars, the more we also understand why we should charge them appropriately. You can, of course, deplete a full battery to a 0% charge and then fill it back up, as you might your computer. But while your computer will have the courtesy to prompt you to save any open files, an empty battery in an electric car means a long wait for a tow truck.
So, what we now know about EV battery packs is that it’s best to charge them only to 80%. EVs are smart enough to know that regularly juicing up the last 20% can be detrimental to the battery’s long-term life. That’s because, among other things, batteries heat up considerably as they get closer to capacity.
The opposite is true when deciding when to charge an EV battery. The best course of action is to allow it to get to only 20% depletion. Yes, that leaves the battery’s actual usage at around 60% of the car’s range, but in a modern EV which may have a 300-mile range, that’s still 180 miles of usable capacity on a day-to-day basis. Few drivers put more than half that figure on their odometers daily.
You can’t go back in time to tell the previous owner of a used EVthey need to follow specific charging protocols, but you can nurture the future health of your EV’s battery.
4. Invest in a Home EV Charger
The best way to charge an EV is to use a Level 2 charger. These are relatively inexpensive for a licensed electrician to install at your home. They’ll first install a 220-volt power outlet, which looks and operates just like what you use for an electric clothes dryer. From there, they can mount an EV charger on your garage wall.
After that, charging is as simple as plugging in when you need to fill up your electric vehicle.
Level 2 chargers offer the best balance between good charging times and energy efficiency. They don’t waste as much energy to heat as Level 1 and Level 3 chargers.
A Level 1 charger is simply a standard three-prong household outlet like you have throughout your house. These don’t provide enough electricity to charge a battery overnight. Conversely, the Level 3 fast chargers you may see around town are helpful in a pinch but can be difficult for many EVs to handle regularly. Think of a Level 3 charger like a gluttonous meal; it’s satisfying, but only occasionally.
5. Download an EV App or Use a Computer for Smart Charging
All but the earliest electric car models will still be compatible with manufacturer-developed smartphone applications that are free to download and allow you to manage the vehicle’s systems remotely. From these apps, you can view the state of charge and a set of specific charging parameters. You can tell the car when you want it to pull electricity from the charger, and you can tell it to cut off charging at a certain level.
An app is the most convenient way to manage the car’s charging, but most vehicles also offer access to these functions through the central touchscreen infotainment screen.
6. Check the Battery Warranty
Batteries have separate warranties from the typical bumper-to-bumper coverage that offers free repair of such failures as power window regulators or infotainment screens.
But not all battery warranties are created equal. Not even close. Your best bet is to contact either the manufacturer or a dealer that offers authorized service for the vehicle you’re looking to buy — a Nissan dealer for a used Nissan Leaf, for instance. They can tell you exactly how much coverage remains based on the amount of mileage shown on the odometer and the original in-service date.
Automakers routinely tweak warranty terms, so you can’t expect to have the same coverage offered four or five years ago.
Finally, you’ll want to read the fine print carefully. Electric car battery failure rates are low, but automakers spell out what level of degradation over what amount of time constitutes replacement of the pack.
See Electric Cars for Sale
Read Related Electric Vehicle Stories:
- Should You Buy an Electric Car or a Plug-In Hybrid?
- 10 Cheapest Electric Cars
- Is Buying a Used Electric Vehicle a Good Idea?
