Electric car battery life: how to preserve your battery

Here's how to preserve your electric car’s battery life and how much a replacement will cost if you need one

Ford Mustang MACH-E

Electric car battery life is one of the main concerns for those interested in buying an EV. Most electric cars use lithium-ion batteries – the same as the ones in your laptop or smartphone – and these batteries tend to lose some of their capacity over the course of their lives. However, while your phone’s battery and the one in your electric car have many similarities, there are significant differences which affect degradation.

Charging or draining a lithium-ion battery from 0-100% is known as a charging cycle, which is the main factor that causes batteries to degrade. Battery degradation is less crucial in a phone, as most people buy a new one every two or three years, or get a new battery for their phone after a while. 

Of course, a car needs to last much longer than that, so most manufacturers fit electric cars and vans with a built-in buffer preventing the batteries from being drained all the way to 0% or completely charged up to 100%. This reduces the amount of charging cycles that take place, minimising the long-term degradation of the battery and maintaining as many available miles as possible.

On top of this, many carmakers provide a standard eight-year or 100,000-mile battery warranty with their electric vehicles, which also covers a certain amount of battery degradation during this time.

On top of this, many carmakers provide a standard eight-year or 100,000-mile battery warranty with their electric vehicles, which also covers a certain amount of battery degradation during this time.

While these factors provide a certain level of security for electric-car buyers, there are additional steps you can take to minimise any battery degradation and maximise your EV’s battery life. After all, a battery replacement for an electric car can be costly, so it's essential to follow best practices and preserve your electric car’s battery health.

Tesla Model S

Five easy ways to prolong your electric car’s battery life

  1. Keep the battery between 20% and 80% charged at all times
  2. Minimise exposure to warm temperatures
  3. Allow the battery to cool down before recharging
  4. Limit your use of rapid chargers 
  5. Don’t leave your car fully charged for long periods
Volvo battery

Should I charge my electric car every night?

You should avoid charging your electric car’s batteries every night. Frequent charging cycles from 0% to 100% can cause your vehicle’s battery to degrade, especially if you’re using rapid or ultra-rapid chargers often, as these refill the battery at a much faster rate. 

If you leave your car charging overnight, using a charger that top ups the battery at a slower rate like most home wallboxes or on-street chargers are the best option, as this will reduce the chances of an entire charge cycle being completed. Most electric vehicles include an on-board buffer that stops the battery from topping up above 80% to protect against degradation, but not all electric cars include this feature. For best practice, try topping up your battery to no more than 80% just to be safe, or simply add enough charge for the next day’s driving and remove the charger. This will help maintain your car's battery health and maximise its available mileage.

How long can an electric car sit without charging?

You should never leave your electric car parked for long periods with 0% charge, as this can cause the vehicle's battery to degrade. Electric cars lose small amounts of charge when parked and not being driven, so it’s essential to check in on your vehicle’s charge level and ensure it remains between 20% and 80%. An electric-car battery replacement can be an expensive procedure, so it's important to look after it and minimise degradation if you want to save money.

Hyundai Ioniq

How much does a replacement electric car battery cost?

There'll be slight variations from car to car depending on the age and condition of the old battery. It's much cheaper to get a third party to fit a good-condition used or refurbished battery. Replacing a 24kWh battery this way should cost around half the price of buying a new one – although that's highly dependent on how much a secondhand pack can be sourced for.

Unless your car's battery has been particularly badly treated, you shouldn’t need a new battery for many years, if it all. A particularly degraded battery should be covered under warranty if your car is less than eight years old.

It may also be that a degraded battery doesn't need to be dumped entirely; it could just be a few faulty cells that need to be swapped out. There are independent electric-car specialist service centres that can carry this job out, for about £500, so it could be worth looking into.

Should I be worried about battery degradation?

Using data from GPS fleet tracking firm Geotab, Select Car Leasing analysed 64 electric cars built between 2012 and 2019 to see how battery degradation affects electric cars, and whether or not newer models are more resistant to the effect. 

The Nissan Leaf was picked as an example, as it was one of the first modern mass-produced electric cars to be sold in the UK. Select Car Leasing's study found those built between 2011 and 2013 will today have around 80% of their battery capacity left.

Earlier modern electric cars are particularly prone to battery degradation, the study claims: a 2013 Leaf lost 3% of its capacity after one year, while a 2015 model lost 6% the first year, while a newer, more advanced 2019 model lost just 1%.

According to the study, the electric (and plug-in hybrid) cars with the lowest percentage battery degradation included the Audi A3 e-tron (0.3% year-one degradation), Tesla Model 3 (0.6%) and Tesla Model X (0.7%), along with other favourites like the BMW i3 (0.9%) and Tesla Model S (1.1%). 

In contrast, at the opposite end of the study's results, some popular models returned some less impressive battery degradation results. The Mitsubishi Outlander PHEV was the worst hit, with 4.1% of its battery capacity lost in the first year. The Kia Niro PHEV lost 3.5%, the Volkswagen e-Golf 1.7% and the Kia Soul EV 1.6%. The popular Volkswagen Golf GTE hybrid didn't fare too well, either, with 1.7% of its battery capacity lost in the first year.

Overall, the study shows that newer electric cars tend to be less prone to degradation – so it pays to choose as new an electric car as you can afford when buying a used one.

Nissan Leaf

What should I do if I’m buying a used electric car?

The most important thing is to check how much of the manufacturer’s original battery warranty is left. It's worth getting the car’s battery status checked at an independent specialist, too. The good news is that – as mentioned above – in some cases it’s possible to change the individual cells rather than the whole pack, which is substantially cheaper.

And if the car's manufacturer battery warranty has expired, you can continue to guard against having to shell out for a battery replacement or refurbishment by purchasing an extended warranty from a third-party supplier. MotorEasy launched just such a warranty in November 2020.

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