Repairing corrosion on a Tesla Model S after the battery warranty has expired


Corroded battery packs and circuitry in electric vehicles are an emerging problem. How much does it cost to repair a corroded Model S battery?

Photos courtesy of Tesla, Inc.

Ask MoneySense

I am the second owner of a 2013 Tesla Model S with 213,000 km on the odometer. Recently my battery range dropped to about 150 km and the car triggered an alert. I took my car to the Tesla service centre in Montreal and paid $420 for a diagnosis. Conclusion: the entire battery pack has to be replaced. The estimate for the replacement is $25,500 plus tax. Tesla was not prepared to help me with the huge cost of this repair because the 8 year/160,000 km new vehicle warranty had expired.

I took my vehicle to an independent shop that specializes in repairs on EVs for a second diagnosis. They determined that corrosion has damaged the battery casing.

As you can see from the images, I keep my car in top shape. Unfortunately, I’m past the battery warranty on my Model S, and Tesla is not prepared to contribute anything toward the repair.

–Montreal, Que.

What causes battery pack corrosion in the Tesla Model S?

Battery pack and battery circuitry corrosion is an emerging issue as EVs and hybrids start to age and accumulate mileage.

I contacted the Montreal-area repair shop that prepared your car’s diagnosis, VE Mtl on 4th Avenue. According to Michael Tempone, director of the service department, the damage is a consequence of water infiltration that creates problems after seven or eight winters or 150,000 km. Tempone says that on the Model S, the location of the air conditioner drain allows condensation to drip onto the battery case, which is a contributing factor. The weakness is compounded by salt and slush on winter roads in eastern North America, creating ripe conditions for underbody corrosion.

The repair involves checking components, replacing or cleaning corroded parts, and protecting the battery case with a better-quality sealer. VE Mtl’s estimate to repair your vehicle is in the range of $4,000 to $5,000. If water damage has impacted modules inside the battery case, the cost can climb to $8,000.

Tempone recommends that Model S and X owners who intend to keep their vehicles for the long haul perform a complete battery reseal before the eight-year factory warranty on the batteries expires. The cost of the service is about $3,500, assuming internal parts have not sustained damage, and it should provide corrosion resistance for the remaining life of a vehicle operated in a high-corrosion environment.

Corroded EV battery packs: not just a Tesla problem

Tesla is not the only electric vehicle (EV) manufacturer experiencing issues with water infiltration or corrosion damage to battery modules or their circuitry. The Automobile Protection Association (APA) has received complaints on the Nissan Leaf as recently as the 2018 model year, and the Ford Focus EV, among others. And Toyota is currently the subject of a class action lawsuit over corrosion of the wiring connection to the rear motor on several of its hybrid models.

Currently, very few aftermarket shops are capable of providing the cheaper workarounds the manufacturers should have developed for their dealerships. Tempone says that the steps involved in repairing a corroded battery pack vary depending on the extent of the damage and the techniques used by the aftermarket shop.

To the APA’s knowledge, Tesla does not perform this sort of work, preferring to replace the entire battery pack after corrosion damage has degraded its performance or rendered the vehicle inoperable.

Read the full MoneySense article here.

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