'Held up quite well': Myths on used electric vehicle battery health debunked

02/14/2025 12:00 AM

Range anxiety caused by battery deterioration is often cited as a major barrier preventing consumers from adopting electric cars.

A June 2024 McKinsey Mobility consumer survey – which polled more than 30,000 respondents worldwide, including from Australia – found that 29 per cent of people said driving range was one of the leading reasons they hadn’t yet made the switch to electric.

RELATED:What I wish I knew before buying a second-hand EV

Adding to that, buyers are also nervous about the high costs associated with replacing an EV’s high-voltage battery. While most experts say EV battery deterioration is inevitable, the process isn’t as fast as some might claim.

According to a report published by Pickles Auction House, on average, EVs older than four years that have travelled more than 120,000km retained over 93 per cent of their battery capacity.

Electric models less than two years old that have recorded up to 20,000km held on to approximately 97 to 98 per cent.

For electric cars aged two to four years old with 20,000km to 80,000km on the odometer, battery capacity decreased to 95 and 94 per cent respectively the report stated.

The auction house said testing on 250 EVs from brands such as Tesla, Hyundai, Kia, BYD, Cupra, Polestar, Nissan, MG and Audi started in October 2023 but stopped short of naming what specific models were used during the evaluation.

"The Pickles EV Battery Health Assurance Process connects with the vehicle's battery management systems. [Test] vehicles were located in all major capital cities that were driven in city and country locations with varying ranges of mileage," Brendon Green, General Manager (Automotive Solutions) at Pickles, told Drive.

Pickles auction house said it used Tesla – the best-selling EV car maker in Australia – as a benchmark to test other EV models. According to the report, on average, a two-year-old Tesla with around 42,000km on the odometer will retain 93 per cent of its original battery capacity.

In comparison, a three-year-old Hyundai EV that's driven around 29,000km will maintain 99 per cent of its battery life on average, while a one-year-old BYD with roughly 15,000km on the odometer will retain 99 per cent too.

David Smitherman, the CEO of EVDirect – BYD’s Australian importer and distributor and the world’s second-largest battery manufacturer – said the data is a reflection on the car maker’s "dedication to [battery] research, development [and] continual improvement".

"At its core BYD’s superpower is that we make the battery [in house] and we invest millions of dollars to make sure that the battery is the best battery, and it’s tried and tested," he told Drive.

"We are very confident and very comfortable that our [EV] batteries will have a long life and will outlast any ICE engine."

Despite buyer concerns associated with battery health in second-hand EVs, a May 2024 study conducted by US-based battery firm Recurrent Auto revealed that outside of major recalls, only 2.5 per cent of EVs built from 2016 onwards needed to replace their batteries.

According to Recurrent Auto's report – which gathered data from 20,000 drivers in the US – battery replacement rates jump to 13 per cent in electric cars built before 2015, showing the state of battery health has improved over the last 10 years.

Beyond the data, early EV adopters have shared their ownership experience of early electric models.

Bryce Gaton, the owner of a 2011 Mitsubishi i-MiEV – one of the earliest EV models to come to Australia – previously told Drive, "I use it as a personal example of how [EV] batteries don’t die the day after warranty runs out".

"I do a lot of public speaking on the topic of EVs, so it is a useful car to point to for a real-life example of it being from the first year of manufacture of modern-day production BEVs but still running on the original battery.

"I’ve done somewhere around 7000–10,000km in three years… it’s held up quite well," he added.

Still, EV battery degradation is inevitable, but various experts and car makers estimate it could take over five years before it shows signs of decline.

To quell consumer doubt, most manufacturers offer extended battery warranties on their electric offerings. For example, BYD offers an eight-year/160,000km warranty, while Tesla offers an eight-year/160,000–192,000km warranty depending on the model.

"In terms of how long [an electric vehicle battery] will last for, our expectation is that it should well exceed the eight years [warranty]," Ben Warren, Nissan’s National Manager for Electrification and Mobility, previously told Drive.

"Ultimately, it’s about how long will it cater to your driving requirements. Someone who doesn’t do much driving won’t ever have to replace the battery, but others who do high mileage may find that they need replacing [after eight years]," he explained.

Dickson Leow, the General Manager of Infinitev – a Melbourne-based company that refurbishes electric and hybrid car batteries – said battery deterioration can happen earlier in the warranty period.

"We know most manufacturers have six, to eight, to 10-year [electric and hybrid battery] warranties, but from lots of enquiries we’re getting [these batteries] are starting to fail around the six-year mark," Leow explained.

EV battery technology is growing all the time, with the batteries themselves improving while innovations in things like vehicle-to-grid (V2G) and vehicle-to-home (V2H) are gathering pace too.

V2G allows EV owners to sell the electricity stored in their car’s battery back into the electric grid during peak periods when the system is under pressure, assuming the driver charges their vehicle using solar power or at off-peak times.

V2H refers to the possibility of electric car owners powering their homes – either for emergencies or weekly use – with the battery effectively doubling as a home battery.

Both systems work using an EV’s bidirectional charging capabilities that allow the transfer of stored electric energy from a car to a home or the grid through a bi-directional charging station.

A recent survey conducted by the NRMA, which polled 1300 members, found that 54 per cent of EV owners would consider installing V2G technology in the future.

Francis Clarke, an electric vehicle owner trialling the V2G system through Amber Electric, told the NRMA, "My car has nearly five times more battery than a home battery. Now I charge my car from solar during the day and send the power back to the grid in the evening when it’s needed to make a profit".

"In May [2024], there was a big power spike where the wholesale price hit the unheard level of over $20/kWh. Amber Electric advised me by SMS, and I was ready for this. I set both the car and home battery to full discharge at 11kW. In two hours I earned $564," he said.

In May 2024, Mitsubishi became the first manufacturer in Australia to install bi-directional charging infrastructure at its headquarters in South Australia, the only Australian state currently offering the technology – though it is expected that other jurisdictions will have it by the end of 2025.

The Japanese car maker was met with regulatory and bureaucratic hurdles during the process, with Shaun Wescott, the Chief Executive Officer of Mitsubishi, calling for the technology "to become a national standard".

"Working with the South Australian [power authorities] was… hard. SA Power Networks has worked with us, and we actually have a bi-directional site working. Our head office is live," Westcott previously told Drive.

"It’s [V2G] gained a lot of traction, it’s gained a lot of publicity, and now you have all kinds of governments quoting bi-directional charging as being the big solution. What we do need is somebody to take – not a pair of scissors – but a hedge clipper to the red tape.

"It’s the future, it’s the way to go. Japan’s been doing it for years. Japan’s an advanced manufacturing society, if it can work there, it can work here too," he added.

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