Electric vehicle (EV) battery technology is a fascinating area if you like you to geek out about physics and chemistry. But most motorists contemplating making the switch to an EV just want to know that the car will provide reliable service, getting them around as safely and expediently as a petrol or diesel car. And a question that’s on a lot of potential EV buyers’ minds is exactly how long do electric car batteries last?
It’s a particularly important question if you’re thinking about getting a used EV. Prices for used electric cars are looking very tempting right now, allowing more people to make the switch. However, some of those used EVs are getting on in years and have high mileage, so it’s perfectly valid to wonder how much longer their batteries will last.
Generally speaking, EV batteries are expected to outlast the cars they power, but the lifespan of a battery depends on how much the elements inside it have degraded. That, in turn, depends on how the car has been used. Without getting into too much of a science lesson, you’ll find out everything you need to know about EV battery life here.
Let’s consider the factors that affect how long your EV car battery lasts:
- The EV battery technology
- How time affects your EV battery
- What are battery cycles?
- How heat can affect the life of your EV battery
- How to maximise the life of your EV battery
- How your electric car warranty protects you and your battery
How long do electric car batteries last?
Batteries don’t last forever. They generate electricity through a chemical reaction between an anode, cathode and electrolyte. These degrade over time, essentially melting away with each cycle of charging and discharging.
The reaction also generates a lot of heat, which itself causes the battery’s components to degrade. A battery ‘dies’ when the components have degraded so much they can’t sustain the electricity-generating reaction.
How time affects EV battery life
Electric car batteries are actually very reliable, as this Geotab study shows. It looked into the health of the batteries in over 6,000 EVs, representing 21 different models, and the results were actually better than expected.
The study suggests that, even if you’re buying a used EV that’s, say, five years old, there should be more than enough life left in the battery to see you through your ownership. The maximum possible range the car can travel may start to decline once it’s eight to 10-years-old, but not by much.
Even if range does drop off, that doesn’t necessarily mean the car is done for. Most EV manufacturers have designed their batteries in such a way that individual cells can be replaced, boosting range back up to what it should be. It’s like changing a single battery in a remote. We’ll come onto whether cell replacement is covered under warranty in a bit.
Incidentally, those old battery cells don’t get thrown away. Instead, they’re repackaged into storage batteries that can be used to power buildings and infrastructure.
How charge and discharge cycles affect the battery lifespan
When you use a battery, the electricity it generates is discharged. The battery runs flat when the chemical reaction going on inside it stops. Recharging the battery sparks the reaction back into life. That’s a very simplistic way of putting it, but you get the point.
Cycles of discharging and recharging a battery degrade the components within. With each cycle there’s a little less material to react with, therefore less power is generated.
When EV batteries are designed and developed, they are put through many more cycles than would be expected in a typical car’s lifetime. So it’s highly unlikely that your EV’s battery will die during your ownership.
However, there are best practice measures you can take to prolong the battery’s life as much as possible. For instance, EV manufacturers recommend you recharge the battery from 20% up to 80% of its capacity whenever possible.
How heat affects the life of an electric car battery
Batteries generate a lot of heat as they produce electricity, which can reduce battery life. More significantly, though, the heat that builds up during charging can also reduce battery life.
A battery is heated up by the flow of electricity going into it. That heat builds and slows down the rate at which the battery can recharge, particularly once it reaches 80% of its capacity. The build-up of heat is also affected by the wattage of the charger – a 150kW rapid charger generates more heat than a 7kW charger. As a result, repeated use of a rapid charger can ultimately limit the life of the battery.
How to prolong electric car battery life
While it’s unlikely you’ll experience significant degradation of an EV’s battery life, it can still happen, particularly in older EVs. But there are ways of prolonging a battery’s life. It’s much like an engine which needs servicing periodically to maintain its health – there are some simple measures you can take to keep an EV battery healthy.
Use slower chargers
Rapid chargers are brilliant for keeping you going on a long journey or getting you out of a pinch when you need juice up in a hurry. However, the heat rapid chargers generate degrade the battery so, if you rely heavily on them, it won’t perform at its peak as long as it could. Using a slower charger like a 7kW domestic wallbox charger won’t degrade the battery to the same extent.
Don’t run to 0%
It’s never a good idea to run any battery completely flat, then recharge it back up to 100%. The heat this generates can deplete battery life quite significantly. It’s also worth noting that an EV with a flat battery is essentially a very large, very heavy brick that can be extremely difficult to move.
Electric car battery warranties
All EV manufacturers provide a warranty that covers the car’s battery, separate from the rest of the car. Indeed, battery warranties often last a lot longer than the ‘whole car’ warranty. Should battery capacity fall below a certain capacity – around 70% – during the warranty period, the manufacturer commits to repair or replace the battery. It’s often just a case of replacing a few cells. You’ll be able to see how far the capacity has fallen just by tracking the maximum amount of charge the battery will accept.
Below, we’ve detailed the battery warranty provided by every EV manufacturer including the age and mileage limits, and the guaranteed minimum charge.
- Audi – 8 years or 100,000 miles
- BMW – 8 years or 100,000 miles, 70%
- BYD – 8 years or 124,0000 miles, 70%
- Citroen – 8 years or 100,000 miles, 70%
- Cupra – 8 years or 100,000 miles
- DS – 8 years or 100,000 miles, 70%
- Fiat – 8 years or 100,000 miles
- Ford – 8 years or 100,000 miles
- Genesis – 8 years or 100,000 miles
- GWM ORA – 8 years or 100,000 miles, 70%
- Honda – 8 years or 100,000 miles, 70%
- Hyundai – 8 years or 100,000 miles, 70%
- Jaguar – 8 years or 100,000 miles, 70%
- Kia – 7 years or 100,000 miles, 70%
- Lexus – 10 years or 100,000 miles
- Mazda – 8 years or 100,000 miles
- Mercedes – 8 years or 100,000 miles, 70%
- MG – 7 years, 80,000 miles, 70%
- MINI – 8 years or 100,000 miles
- Nissan – 8 years or 100,000 miles, 75%
- Peugeot – 8 years or 100,000 miles, 70%
- Polestar – 8 years or 100,000 miles
- Porsche – 8 years or 100,000 miles
- Renault – 8 years or 100,000 miles, 66%
- Skoda – 8 years or 100,000 miles, 70%
- Smart – 8 years or 125,000 miles
- SsangYong – 7 years, 90,000 miles
- Subaru – 8 years or 100,000 miles
- Tesla – 8 years or 100,000 miles, 70%
- Toyota – up to 10 years
- Vauxhall – 8 years or 100,000 miles
- Volkswagen – 8 years or 100,000 miles
- Volvo – 8 years or 100,000 miles
