EV Battery Lifespan: What You Need to Know

For many car owners, the electric car represents an entirely new way of driving and brings with it many queries and worries. One of the largest concerns is how long the battery life is on an electric car. You may well have read horror stories about electric car owners facing hefty bills for replacements or contemplating cutting their losses on cars that are otherwise worthless because they literally don't work. And it’s not hard to see where these rumours and anecdotes come from, because our extensive experience of mobile phones, tablets, and laptop computers has shown many that, even over a relatively short period of time, the batteries powering them can quickly lose efficiency, resulting in the need for more frequent charging. In extreme cases, the degradation is so severe that the device won’t even fire up unless it’s permanently on charge, which is obviously no use for an EV. There’s also no denying that battery technology doesn’t come cheap, and should the cells ever need replacement, it’s quite likely that they will cost more to swap than the car is now worth – which is why we tend to replace mobile phones in their entirety rather than replace the battery pack. Battery swapping stations, where depleted electric car batteries can be changed for fully charged ones in mere minutes, are beginning to crop up in Europe and may offer an answer to battery life queries. But how bad is the electric car battery problem really? The good news is that the more electric cars that are out there and the longer they are run for, the more evidence is produced to show that the power pack will often last the lifetime of the car.

Understanding EV Battery Degradation

The term 'degradation' refers to the gradual loss of capacity in a battery over time and use. It's a natural process for all rechargeable batteries, including those found in electric vehicles. While it's true that EV batteries do degrade, the rate at which this happens is often much slower than many people fear, especially when compared to the batteries in smaller electronic devices. Modern EVs are equipped with advanced battery management systems (BMS) that play a crucial role in monitoring and optimising the battery's health, mitigating the effects of degradation.

Factors Affecting EV Battery Lifespan

Several factors can influence how long an EV battery will last and how quickly it degrades. Understanding these can help you maximise your battery's longevity:

Charging Habits

How you charge your EV has a significant impact:

• Regularly fully charging or entirely depleting your EV’s battery can degrade it more quickly. Keeping the charge level between around 20% and 80% is optimum to make your battery last longer. It’s no coincidence that car makers often quote charging times to 80%, rather than full.
• The frequent use of DC rapid chargers can also have a detrimental effect on the life of EV batteries. Rapid charging is the quickest way to refill an EV battery, and the fastest public charge points can top them up to 80% in 30-40 minutes. EVs have sophisticated battery management systems to help calm the effects of rapid charging and protect the batteries from overcharging. This is why rapid chargers begin to ‘taper’ (reduce the power they deliver) once batteries are more than 80% full. Despite this, studies have shown battery degradation can increase when compared to slower AC charging.
• If you’re charging more slowly via a home charge point or a domestic socket, charge overnight when the ambient temperature is lower to preserve battery health. Another tip is to use the car as soon as you can after it has finished charging.
• If your EV is going to sit around without being driven or only used locally, don’t fully charge it first. Keep the battery around half full, as this is better for its long-term health.

Driving Style

Your driving habits also play a part:

• Aggressive acceleration and hard use also speed up battery wear. It will also reduce the range between charges, so it’s much better to take things slow and steady.
• Avoid extreme temperatures if possible, too, as these can reduce the car’s range and battery performance.

Temperature

Extreme temperatures, both hot and cold, can affect battery performance and longevity. Prolonged exposure to very high temperatures can accelerate the chemical degradation within the battery cells. Conversely, while cold weather primarily impacts the *instantaneous* range, very cold conditions during charging can also be detrimental if not managed correctly by the BMS.

How Often Should Electric Car Batteries Be Charged?

Electric car batteries tend to suffer if exposed to extremes of temperature, and particularly if the battery’s temperature itself rises. This is why overcharging is limited by a car’s on-board computer, and many electric cars use cooling systems when charging to prevent overheating. Certain charging behaviours can accelerate battery degradation, with the most common being regular rapid charging and ‘deep discharge’ – that is, using the full capacity of a battery repeatedly. Many electric car manufacturers recommend only charging to 100 per cent when the full range is required for a big trip. For example, MG suggests only charging between 20 and 80 per cent to extend battery life, and not to let charge drop below 50 per cent ‘too often’.

Expected Lifespan and Warranties

The good news is that most EV manufacturers offer substantial warranties on their battery packs, typically covering eight to 10 years, or around 100,000 miles, whichever comes first. These warranties usually guarantee a certain percentage of the original battery capacity (often 70% or higher) will remain over the warranty period. This provides a significant safety net for early adopters and demonstrates the manufacturers' confidence in their battery technology.

What Happens When the Battery Degrades?

There are a number of possible outcomes if an electric car battery has degraded to the point that it is unusable or significantly diminished in performance:

• Battery Leasing: If the battery was leased under a separate agreement – a model that was more common in earlier modern electric cars from manufacturers like Renault – the battery will be replaced or repaired free of charge if it’s found to have degraded, usually when a battery gets to about 60 or 70 per cent of its original capacity.
• Separate Battery Warranty: Much more common today is a battery with a separate warranty to the car itself. These usually run for eight or 10 years, with a common limit of around 100,000 miles – more than enough to cover most buyers’ typical three- or four-year tenure with a car on a finance deal. The same 60 or 70 per cent performance degradation rule usually applies, but battery replacement agreements vary.
• Out of Warranty: If you own the whole electric car, perhaps used, and the battery is out of warranty, all you can do is buy a new battery or repair the existing unit. Replacement will cost several thousand pounds in most cases, so it’s a good idea to pay close attention to the condition of the battery in any purchase of a higher-mileage electric car – just as you would with the engine and gearbox of a petrol or diesel car. You can expect old or higher mileage used cars to have significantly reduced battery capacities and shorter ranges but they are still perfectly usable unless the battery actually fails – which is a rare event. Electric car battery repairs are possible with many specialist companies now offering these services for older cars that are out of warranty.

What Happens to Old Batteries?

When a typically degraded electric car battery is removed from a car, it generally doesn’t head straight for landfill. There are countless companies making the most of these batteries, either through conversion for other applications (such as stationary energy storage) or via recycling of their valuable constituent components, including nonferrous, precious, and rare-earth metals. This circular economy approach ensures that valuable resources are recovered and reduces the environmental impact of EV ownership.

Battery Lifespan Comparison Table

Here's a simplified comparison of factors affecting battery life:

Frequently Asked Questions (FAQs)

Q1: Will my EV battery need replacing soon after buying the car?

No, this is highly unlikely. Modern EV batteries are designed to last for many years, often exceeding the typical ownership period of a car, and are covered by long warranties.

Q2: How much does an EV battery replacement cost?

Replacement costs can vary significantly but are typically in the thousands of pounds. However, this is often mitigated by the long lifespan and warranty coverage. For a car out of warranty, repair specialists may offer more affordable options than a full manufacturer replacement.

Q3: Can I extend the life of my EV battery?

Yes, by following best practices such as maintaining the charge between 20-80%, avoiding excessive rapid charging, moderating your driving style, and minimising exposure to extreme temperatures.

Q4: What happens if my EV battery degrades significantly?

If the degradation occurs within the warranty period, the manufacturer will typically repair or replace the battery. If out of warranty, you would need to cover the cost of replacement or repair yourself.

Q5: Are electric car batteries environmentally friendly?

While the manufacturing process has an environmental impact, the lifecycle emissions of EVs are generally lower than those of internal combustion engine vehicles. Furthermore, the recycling and repurposing of old EV batteries significantly contribute to their environmental credentials.

Conclusion

The concern over electric car battery lifespan is understandable, but the reality is that modern EV batteries are robust and durable. With proper care and adherence to manufacturer recommendations, an EV battery can indeed last for the lifetime of the car. The advancements in battery technology and management systems, coupled with comprehensive warranties, mean that the fear of costly, premature battery failure is largely unfounded for most EV owners. By understanding the factors that influence battery health and adopting good charging and driving habits, you can ensure your electric vehicle serves you well for years to come.