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Electric car batteries explained

Your jargon-free guide to how electric car batteries actually work, how to look after them, how long they last and how electric car batteries are recycled – plus much 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? 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 distance a battery will take you between charges is generally referred to as 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?

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. Confusingly there is no standard measure for efficiency in EVs and, depending on the manufacturer, you may encounter miles/kWh or kWh/100km (or kWh/100 miles) on your trip computer. You’ll probably get used to whichever your EV uses pretty quickly, and the mental arithmetic for working out how much range you’ll get for your kWh quickly becomes second nature.

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

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 per cent and 80 per cent 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 per cent, which is why public charging points often quote the time it takes to charge a car to 80 per cent. 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

How do I know if my electric car battery needs replacing?

It’s a good idea to monitor the health of your car’s battery, as without it you won’t be getting far. There are generally tell-tale signs to let you know your battery’s life is coming to an end, so keep an eye out for these:

Dashboard warning symbol

The most obvious sign that your battery needs replacing would be an illuminated battery symbol on your dashboard, indicating a fault. This should not be overlooked, especially if it stays on whilst driving. The last thing you need is to be stranded in the middle of nowhere, so if it pops up, get it checked as soon as you can.

Electrical issues

The battery doesn’t just start up your car, it’s responsible for all your car’s electrics, from the lights to the computer system and even that handy charger port for your phone. If you start noticing issues with the electrics, for example the lights dimming or a loss of electrical power to, say, your heaters, you might want to get it checked out.
Renault Zoe
Renault Zoe

Used electric car batteries

If electric car batteries last between 10 and 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 versus 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
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.
Silver Mercedes Benz EQC parked in front of a bridge
Mercedes Benz EQC

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 interior
Porsche Taycan interior
Porsche Taycan interior

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.

Are electric car batteries bad for the environment?

Battery electric vehicles don’t produce any tailpipe emissions like carbon monoxide and nitrogen oxides, so they’re definitely cleaner. Of course, this doesn’t mean EVs don’t have a carbon footprint – pretty much 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 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 – and that’s right now. The future of EV batteries looks much brighter. Related: How green are electric cars?.
Zipcharge portable electric car charger
Zipcharge portable electric car charger

Can you recycle electric car batteries?

The actual lifespan of an EV battery is longer than you’d think because they face quite strict criteria – such as holding at least 80 per cent of their charge over a certain period of time and discharging less than five per cent when resting. Each manufacturer has its own warranty stipulations such as within seven or eight years and a mileage limit of 100,000 miles, for example, so it’s a good idea to get familiar with the small print or you might end up having to fork out for one yourself.
Mass disposal of electric car batteries is often prevented by regulation, and rightly so. Instead, the battery can be re-used or recycled.

Re-using electric car batteries

Some batteries are already being re-used as energy storage units or back-up batteries for buildings, and there’s currently lots of research going into other ways they can be repurposed when they are no longer suitable to power your car.
Manufacturers have already started taking initiative in this area, putting plans into place to keep EV batteries fed back into the energy cycle of their own factories, creating a closed-loop system for repurposing and recycling. Factories in the future could be powered by the repurposed batteries they originally created – imagine that!

Recycling electric car batteries

When EV batteries reach the end of their functional life, they can be stripped for valuable materials including lithium salts and cobalt, meaning we don’t have to solely rely on the extraction of new raw materials out of the earth.
Tesla already recycles batteries from its vehicles, addressing the issue directly on its website, explaining that none of their lithium-ion batteries go to landfill and that 100 per cent are recycled. Volkswagen’s pilot recycling plant for used electric car batteries has also begun operations with a target of recycling over 90 per cent of its batteries in the future. Northvolt recently produced its first battery cell made “100 per cent from recycled nickel, manganese, and cobalt,” which is a huge step forward towards sustainability for the automotive industry, with the company announcing plans to recycle a whopping 125,000 tonnes of batteries each year in the future. There’s still a way to go, with only approximately half of the materials in an EV battery pack currently being recycled, but hopefully this will continue to improve over the next decade as we move into the electric era.

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