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Electric car batteries explained

Jargon-free guide to how electric car batteries actually work, how to look after them, how long they last and more.

EV car batteries explained

Electric vehicle batteries have come a very long way over the last few years, so it can be hard to keep on top of where we are with it all.
How long will electric car batteries hold their charge for now? How long will they last before they need replacing? Can they be recycled? How long do they take to charge these days? In this article, we take a fresh look at the latest tech in electric car batteries – including top maintenance techniques to prolong your battery’s lifespan and get the most for your money. Jump to: • How do electric car batteries work?How long do electric car batteries last?Electric car battery jargon: kWh, Ah and battery typesElectric car battery life: maintaining, replacing and warrantiesUsed electric car batteriesLeasing or buying electric car batteriesCan you recycle electric car batteries?

How do electric car batteries work?

For most of this article, we’ll be talking about battery-electric vehicles (BEVs), commonly called electric vehicles (EVs) or electric cars. You can get your head around electric car jargon here.
Starting with the very basics: battery electric vehicles run purely off electricity, and that electricity is stored in a battery pack in the car. The electricity stored in this battery pack is used to power the electric motor, which turns the wheels when you drive. Easy.

How do electric car batteries charge?

When your electric car batteries are depleted, they’ll need to be recharged – normally from the grid. To access the grid power, you’ll need to use either a wall socket or an EV charging unit.
You can charge your electric vehicle at home, which is often cheaper and more convenient. Here’s how to work out how much it’ll cost to charge your EV at home. If you need to charge when out and about, or where you live won’t support home charging units, then you can use chargers made available in public or at work. How long it takes an EV battery to charge will depend on the size of the battery and speed of the charging point. Learn more about charging an electric car here.
White Mercedes Benz EQC charging
Mercedes Benz EQC charging
White Porsche Taycan charging in a blue public charging spot
Porsche Taycan charging in public

How long do electric car batteries last?

The length of time an electric car battery lasts between charges is called its range. The range of an electric car varies by make and model, but you can generally expect to travel between 150 and 250 miles in a modern electric car before you need to recharge.
Learn more about an electric car’s range. Electric cars often include energy-saving features to help prolong a battery’s charge. These can include “idling” (where the car turns off when stopped to prevent wasted energy) and “regenerative braking” (where the battery charges when you brake). Keep an eye out for those if you’re shopping for a new electric car.
Audi e tron parked against a dusky sunset
Audi e tron

The science behind electric car batteries

When you start looking at electric cars, you’ll come across some technical terms, like kilowatt-hours (kWh) and ampere hours (Ah).
These are used to explain the capacity of the batteries, which is how much power they hold (and so how much you can use before you need to recharge). If it's been a while since you took your last science exam (same here), then here's a refresh on what they all mean.

What are kilowatt hours?

The capacity (how much the battery can store) of most electric car batteries is measured in kilowatt-hours (kWh). This is essentially the electric equivalent of miles per gallon.
So, in a real-world example, if you drive a Tesla Model S with a 75 kWh battery and a range of 230 miles, you should get around 32.6 kWh per hundred miles.

What are ampere hours?

If an electric car’s capacity isn’t specified in kWh, it’ll likely be listed in ampere hours (Ah). Ampere hours measure the charge delivered by the battery, and kilowatt-hours measure the energy delivered.
If you’re comparing models, then look at the battery’s voltage and use this calculation: current in Amps x voltage = power in Watts. (Don’t forget a kilowatt is 1,000 Watts.)
EV dashboard showing the mileage and battery capacity
EV dashboard
Silver Mercedes Benz EQC driving through a city
Mercedes Benz EQC

Types of electric car battery

This is an easy one. Most, if not all electric cars use Lithium-ion batteries now. They’re the current standard and offer a longer range and retain energy better than other battery types, which in the past have included lead acid and NiMH (nickel metal hydride) batteries.

What are solid state batteries?

If you're swotting up on electric cars, you might hear a bit of buzz about solid state batteries. Solid state batteries are a new technology that are said to offer shorter charging times and greater ranges than lithium-ion batteries.
Early word says solid state batteries are likely to be smaller and they could be reasonably cheap too. BMW, Toyota and Volkswagen are currently set to start mass-producing solid-state batteries by the mid-2020s, so they’re a while off yet.
Volvo XC40 Recharge in Glacier Silver
Volvo XC40

Electric car battery life and maintenance

Ok, the bit we're most bothered about - how do we get the most out of our electric batteries and stop them from going flat?
How long your battery lasts (its lifespan) will depend on a number of factors, including how often it’s charged. You can extend the lifespan of most EV batteries by keeping them charged between 50% and 80% as much as possible. Why? Well, recharging the battery generates heat, and too much heat (caused by keeping your electric car fully charged) can damage the battery over time. To combat this, some electric cars stop charging altogether when they reach capacity. Others slow down their charging for the last 20%, which is why public charging points often quote the time it takes to charge a car to 80%. There are other ways to prolong your battery’s lifespan, including: • Keep an even temperature – extreme hot or cold can negatively affect the battery’s range and its lifespan • Don’t rely on fast chargers – they’re fine to use when needed, but a slow charge is better for your battery in the long term. • Avoid charging your car straight after a long drive – give the batteries chance to cool down first.
Close up of a white Nissan Leaf's badge
Nissan Leaf
Close up of a white Nissan Leaf's interior
Nissan Leaf

Electric car battery warranty

Still a bit nervous about trusting a battery to get you around? You're not the only one, which is why many manufacturers are offering electric car battery warranties for added peace of mind.
The length and details of the warranty will depend on the car manufacturer, so make sure that’s on your list of questions to ask when you’re close to buying an electric car. Most manufacturers, including Nissan and Toyota, offer an eight-year (or 100,000 miles) warranty on their electric car batteries. This normally covers the battery degrading to a certain degree, so you should be well covered.

Will I need to replace an electric car battery?

Most electric car batteries last at least 10 years - a full decade. Some last up to 20 years, so don’t worry too much about the cost of replacing the battery before you’ve even bought a new car - how many of us drive the same car for 20 years?
That said, there may be other reasons your battery needs replacing. Leaving your battery flat and your car out of use could result in the battery pack no longer accepting charge (this is called bricking), but a lot of EVs have systems that prevent the battery fully depleting. It's natural for a battery to lose its capacity over time. This is often due to extended use, and can be slowed by taking good care of the battery. In the event of a battery fault, consult your warranty first.
White Polestar 2 (2020 edition) parked against a storage unit
Polestar 2 2020

Used electric car batteries

If electric car batteries last about 10 - 20 years, does that mean the used electric car market is a game of roulette with battery quality?
Not really, but if you’re thinking of buying a used electric car, you should factor in the battery that comes provided. If the car is a few years old, you might (but not always) have more of an issue with how well the battery keeps it charge. Replacing the battery could cost a lot of money – at which point you have to consider the pros and cons of leasing vs buying an electric car battery (which we'll cover in a minute). Look into testing the electric car battery's health as part of the test drive, or explore your extended car warranty options cover an electric car battery.

What to look for in a used electric car battery

If the car has been driven regularly, and the battery has been correctly charged and discharged, it should be in decent condition. However, the battery may have a shorter lifespan if it’s been charged a lot using a rapid charger or frequently left to go flat.
Older electric car batteries don’t tend to hold their value as well, so although buying a used electric car might be relatively affordable – you should also factor in the cost of replacing the battery or leasing a battery on top of the price of purchasing the car, just in case it’s needed. Don’t let this deter you though. Most electric batteries come with a separate warranty, which will likely last at least five years (with most having eight years) so that should offer some peace of mind. Check with the seller about how long there is left on the warranty and try asking them about their charging history too.
White Tesla Model S parked underground, surrounded by grafitti
Tesla Model S

Buying or leasing an electric car battery

Because battery technology has improved so much, few manufacturers still offer the option to lease a battery. You may, however, still face this decision if you’re looking at older electric cars – especially on the used car market.
So, which is best?

Should I lease an electric car battery?

One advantage of leasing is that you don’t need to worry about replacing the battery if it’s faulty or it’s at the end of its life, which could be good for much older EVs.
The downside, depending on your budgeting, is you’ll have to pay monthly. How much it costs to lease an electric car battery will depend on the length of the lease and annual mileage, but on average you’d pay between £50 and £100 per month.

Should I buy an electric car battery?

Buying an electric car battery means there’s no monthly lease fee and no mileage cap. You will, however, have to pay for a new one (and they’re not that cheap) if there’s a fault after the warranty is up.

What to consider when buying or leasing electric car batteries

If you do have the choice between buying or leasing, you’ll need to look at the specific make and model and weigh up what works best for your budget and driving styles.
You should also consider the battery’s lifespan, plus any warranty or protection schemes it comes with, and the cost of replacing it should you need to.
BMW i3 interior
BMW i3
Porsche Taycan interior
Porsche Taycan

Are electric car batteries expensive to run?

Overall, electric cars are cheaper to fuel than petrol or diesel cars. As they have fewer parts, they’re cheaper to service too.
But they can cost more to insure, and your monthly costs can go up further if you’re leasing a battery, so write everything down and work out how much the specific car you’re looking at would cost in total. Or, work out your budget first and find a car that fits. There’s a good choice available now, so you’ll likely find one you can afford. See how much it costs to charge an electric car here. For a guide to the cost of buying an electric car, take a look at Compare the Market's handy Global EV Index, which compares the price of the Nissan Leaf across the world.
Silver Mercedes Benz EQC parked in front of a bridge
Mercedes Benz EQC

Are electric car batteries eco-friendly?

Battery electric vehicles don’t produce any tailpipe emissions like carbon monoxide and nitrogen oxides, so they’re cleaner. Of course, this doesn’t mean EVs don’t have a carbon footprint – almost everything does.
Generating the electricity needed to power EVs can produce pollution and may also produce greenhouse gases like carbon dioxide. The amount of pollution created depends on how the electricity is made, with renewable energy sources like wind and solar power being among of the cleanest. Studies have found that battery electric cars produce the least pollution in their lifetime (from being built to being scrapped) so while they’re not perfect, they are the eco-friendliest option. Related: How green are electric cars?.

Can you recycle electric car batteries?

Once electric car batteries reach their end of their life, you have a couple of options.
If the battery may be disposed of if it's damaged, but mass disposal is often prevented by regulation. Instead, the battery can be recycled or re-used. Electric car batteries face quite strict criteria – such as holding at least 80% of their charge and discharging less than five percent when resting. So even when they’re no longer up to the task of running your electric car, they’re suitable for a lot of other jobs. Some are re-used as energy storage units or back-up batteries for buildings, among other jobs. If the batteries use valuable metals, like cobalt and nickel, then they can be stripped for recycling.

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