How long do electric car batteries last?

The continuing advances in technology and battery management systems mean that while it is true that electric cars lose battery capacity over time, there is no need to panic or be put off from purchasing an electric car.

In addition to hot potato topics such as EV charging, you may hear vociferous views levelled at electric car batteries losing efficiency, resulting in reduced range and the need for more frequent charging. Anonymous keyboard warriors may claim that the batteries in electric cars are like the ones in your phone: only designed to last a few years, after which point your new car purchase will be destined for the scrapheap.

Well, you’ll be relieved to hear this is not true, but rather than be driven to apoplexy, we wanted to share a few pointers that will help inform your car-buying decision and knock this sort of misinformed pub ammo into the weeds.

An electric car battery can last years

All batteries degrade over time and with use, but it’s the rate and timelines over which this degradation can occur that needs clarity. The truth is that electric cars benefit from sophisticated cooling and battery management systems that guard the long-term health of their batteries and this technology is continually advancing.

Electric car batteries are lasting much longer than anybody predicted

Take the Nissan LEAF, for example. What is considered the first mass market electric car has now celebrated 12 years in production and passed its half-a-million units milestone. Want to know the number of vehicles that have experienced battery failure? Three. That's less than 0.0006%!

A Nissan LEAF taxi from England called ‘Wizzi’ is just one of many long-legged examples to have clocked up more than 170,000-miles on its original battery, and now has been sold to another happy owner. The used car market is reacting to these positive shifts too, with resale values of electric cars continually strengthening.

As more fully-electric models are released onto the market, the real-world evidence of battery longevity continues to build. Geotab is a UK fleet management company that has developed an electric vehicle battery degradation tool to specifically measure the health of electric car batteries. It has found that across 6,300 cars, including models from BMW, Tesla and Volkswagen, the average battery capacity after five years was still 89.9 per cent of the original value.

And remember this includes early electric cars that didn’t benefit from the sorts of battery pre-conditioning software that’s commonly found in today’s electric cars.

Carmakers are well aware that potential buyers are concerned about the longevity of electric car batteries, which is why they offer additional battery-specific warranties that often far exceed their typical vehicle warranties.

Volkswagen, for example, states the usable capacity of the battery in its range of ID electric cars will not fall below 70% within eight years, while the Lexus UX300e is the first vehicle to feature a 10-year, 1,000,000km warranty on the battery pack. If that’s not confidence in the technology, we don’t know what is. 

You can recycle an electric car battery

Electric car batteries will always find another place to be useful

At the end of an electric car’s life, the retained value embedded in the battery means that there are multiple ways of re-using it. For example, degraded battery packs could be sweated in more benign operations like domestic energy storage.

Battery storage can be used to provide low cost energy for your home, and is a much smoother, kinder charging cycle compared to the uncontrolled discharge of stopping, starting and accelerating up to motorway speeds in an electric car.

But as we’ve established, you’re going to be waiting a while for an electric car battery to be repurposed in this manner. For example, Tesla’s Powerwall home battery storage holds 13.5kWh, so even in a worse case scenario, you’ll be enjoying a standard Tesla Model 3 for more than 20 years before having to think about this battery’s next adventure.

Beyond the home, old EV batteries are popping up in all sorts of spaces: Nissan is using them to store energy from solar panels and wind turbines at its new gigawatt factory in Sunderland, as well as power the Johan Cruyff Arena, while Audi is using old e-tron test batteries to help stabilise Berlin’s grid.

Electric car batteries can be preserved and prolonged

Fortunately, there are ways to make sure your electric car’s batteries can stay healthy for even longer. When looking at charging, one of the major ways of protecting the cells is by carefully managing the charging cycle which, in an ideal world, means trying to avoid the battery capacity dropping below 20% and not adding more than 80% when charging. 

Weirdly, batteries don’t actually enjoy being left fully charged. That’s because heat is the enemy of battery systems and lots of heat can be generated from both ultra-rapid charging and keeping the battery at high-voltage. While batteries like to be cycled and used, the general rule is not to be too reliant on ultra-rapid charging, nor to overcharge the battery or let it go completely flat. The risk in all of these scenarios is that dendrites can form, which are like weeds in the garden of battery chemistry that cause cell failure.

Lots of heat is also produced if you like showing off to your friends how quickly your electric car can accelerate from a standstill. When you select Ludicrous+ mode on a Tesla, it actually warns you that you’ll be impacting the battery life. Smooth, steady progress is the name of the game, both for your passengers and your battery’s longevity.

Fortunately, the sophisticated battery management systems in electric cars can regulate power if you’re competing in too many drag races, as well as create artificial buffers at the top and bottom of a battery’s capacity to ensure cells in the battery pack don’t overcharge or over-discharge.

Look after your electric car battery and it will look after you

Battery management systems in performance electric cars like the Porsche Taycan, for example, can even work with satellite navigation, so it knows to pre-condition the battery when approaching an EV charging station. 

Ambient temperature is another factor that needs consideration, because extremes of heat and cold can negatively impact a car’s battery life. This is where battery packs that feature active thermal management degrade less than those that rely on air cooling, because they’re better at maintaining a stable temperature range for the battery.

Regardless, checking the health of an electric car battery is easier than you think. What is referred to as the battery’s State Of Health (SOH) can be reviewed from accessing the car’s main menu or you can ask your dealer for a full diagnostic review at your next service.