Tesla Model S Owner Upgrades The Battery After 470,000 Miles: ‘Nearly Double The Range’

• A 2015 Tesla Model S with 470,000 miles had its high-voltage battery upgraded.
• The old 70 kWh pack was swapped for a newer, 100 kWh battery.
• The job cost about $12,000, but the owner, who did the upgrade himself, says it was worth it.

Getting a second-hand Tesla Model S can be a great deal, seeing how a first-generation car starts from around $6,000 on the used market. However, the big unknown is the high-voltage battery, which can lead to a $20,000+ repair bill.

But there are more budget-conscious solutions out there, including swapping in a higher-capacity pack from a newer car. That’s what Alex from Out of Spec Renew did to his 2015 Tesla Model S, which came from the factory with a 70-kilowatt-hour battery. 

The car, which has a little over 470,000 miles, was already on its second pack, which was installed at around 200,000 miles. So when the opportunity to swap in a 100 kWh pack appeared, Alex, who runs an EV repair shop, jumped on it. We wrote about this particular car on a couple of occasions in the past, including the upgrade process and the costs associated with it.

So, for around $12,000 and a few days in the shop, is it worth it? According to Alex, it certainly is, and the charging stats are there to prove it. With the old battery, the charging power would never go above 100 kW, so a 15-minute Supercharger session started at 10% state of charge would result in just 15 kWh of energy added and a 25% bump in the battery level. As for the range, that 15-minute top-up, which is usually the norm for fast-paced road trips, enabled 41 miles of driving at a constant 80 miles per hour

With the new battery–new for this particular car, but it was taken off another Model S–the stats are much better. The same 15-minute charging stop, where the car was plugged in at 10%, allowed the car to take in 29 kWh of energy, with the state of charge indicator going up to 44%. That’s thanks to the higher charging power that the larger pack could sustain for a longer period of time, with a peak of 132 kW.

After driving the car on the highway again, the total distance covered before hitting 10% again was 76 miles–35 miles more than with the old pack. That’s an 85% improvement in usable range. And it could have been even better because the battery wasn’t up to the ideal temperature when it was charged, and the ambient temperature was about 10 degrees lower. But great result nevertheless.

That said, the car’s efficiency dropped by about 5%, most likely due to the increased weight of the larger pack, which is about 300 pounds heavier than the old pack, but also because the air is denser when it’s cold out.