How long do Tesla batteries actually last? We crunch the numbers

10/03/2024 03:04 PM

Back in 2019, Elon Musk tweeted that the battery in a Tesla Model 3 would last for between 300,000–500,000 miles (482,000–805,000km). Flash-forward to 2024, and just how accurate was his estimation?

As one of the first car brands to sell electric cars to a broad consumer base, Tesla has more real-world data on its average battery lifespan than any other EV manufacturer.

RELATED: How much does it cost to charge a Tesla at a Supercharger in Australia?

Given it's also the top-selling electric car brand in the world, there are also scores of Tesla owners out there willing to share their real-world ownership experiences over the past decade or more. 

As such, we've got enough information to piece together a relatively reliable portrait of Tesla battery lifespan – with the help of battery chemistry experts who've done the heavy lifting on the research front. 

Here's what you need to know about how long the batteries in Tesla vehicles last in the real world. 

What is Tesla’s battery warranty?

Tesla warrants its batteries for eight years or 160,000km on rear-wheel-drive Model 3 and Model Y models, or eight years and 192,000km for all other Australian-delivered vehicles. 

Under this warranty, Tesla guarantees the battery will retain a minimum of 70 per cent of its capacity over the stipulated period. If battery capacity drops below 70 per cent in this time, Tesla will cover the cost of a replacement battery – which can be as high as $20,000. 

This 70 per cent benchmark is crucial, as electric cars start to see battery issues once their capacity drops below this point. That could mean they are slower to charge, or achieve noticeably less range than they did when new. 

How long do Tesla batteries last?

According to Tesla's official data, Tesla batteries lose between 12 and 15 per cent of their capacity on average after 200,000 miles or 321,868km of usage.

Given ABS data shows the average Australian driver travels 12,100km per year, this should theoretically mean you won't need to worry about a significant loss of capacity for the first 26 years of ownership. 

An April 2024 report by British personal finance site NimbleFins gathered nine years of real-world data from Tesla owners and found that, on average, their cars lost about 1 per cent of their range yearly. 

Based on this data, Tesla owners should expect their batteries to retain more than 80 per cent of their range for at least the first 10 years of ownership.

Dr Adam Best, Principal Battery Researcher at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), agrees that the batteries in modern electric vehicles can manage a "pretty impressive cycle life" when properly maintained.

"There are examples of Tesla taxis doing half a million miles [804,672km]," Dr Best told Drive. 

"Jeff Dahn [a lithium-ion battery research pioneer] in Canada worked very closely with Tesla for many years … he talks about the fact that if you run [the batteries] in the right voltage window and the right conditions, you'll get 100 years or a million miles out of them." 

Meanwhile, Zoltan Sekula, product stewardship manager at Australian battery recycling company EcoCycle, says consumers can comfortably expect their electric car battery to last for at least the minimum warranty period.

"Manufacturers say eight years or 150,000km – so it's very unlikely your battery is going to fail in that time," Mr Sekula said.

"There will always be manufacturing defects, so there is a percentage of batteries that will fail just because it was a Monday, but all the recalls issued so far [in Australia] have been battery module issues. It's because manufacturers have been playing it safe – it's based on a very small number of incidents, the problem is the potential repercussions." 

Of course, the potential for Tesla battery life to vary by individual owner is massive and depends heavily on owners employing best-practice maintenance techniques to prolong battery health.

How to make your Tesla battery last longer

Dr Best says doing "partial state of charge cycling" can lead to "tremendously long life cycles" for electric car batteries.

"We as scientists measure cycle life as 100 per cent charge to zero, but when you're driving you'll hardly ever go from 100 to zero per cent, you'll do 90 to 40 per cent and batteries prefer that," he told Drive. 

“Keeping the charge level between 20 per cent and 80 per cent can help to extend the life of your EV."

This holds true regardless of battery chemistry. Tesla predominantly uses either lithium iron phosphate (LFP) or nickel cobalt aluminium (NCA) chemistry in its batteries, while other brands like Polestar use a chemistry called nickel manganese cobalt (NMC). 

"Typically, if you use the NMC and NCA chemistries at 100 per cent state of charge (SoC), you will stress the battery and will see the performance and life decay," Dr Best told Drive.

"However, if you charge these chemistries to 80 per cent, and only occasionally to 100 per cent SoC, that's when you will see no difference in performance between NMC/NCA and LFP battery chemistries – many long years of driving!”

Similarly, Tesla advises its owners to "avoid keeping the battery below 20 per cent charge for an extended period of time". 

Additionally, the CSIRO suggests that frequent fast charging – for example, via the likes of Tesla's 250kW Supercharging network – can also accelerate battery degradation.

Relying on slower AC charging up to 7kW – often described as ‘trickle charging’ – can help prolong battery life. 

Tesla cars actually have built-in technology to assist owners in maintaining optimal battery health.

The car maker advises owners to "charge the battery to the appropriate charge limit for your vehicle based on the installed battery". 

"To adjust the charge limit for your vehicle, open the Charging screen on your touchscreen or in the Tesla app and drag the slider," the brand's official website states.

"Different batteries require different charging routines for optimal performance. Your vehicle's touchscreen will display the recommended charge limit for your battery."

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