NOTE: The arbitration of this dispute has finally rendered a decision. I have reported the outcome in this post.
My Battery
Warranty Dispute
with Tesla

February 19, 2022

Model 3 Battery Pack
(Click to enlarge)

The Breakdown

In early January 2020, by pure chance I happened to notice that, after plugging in my Model 3 to recharge in my garage, the charging rate was lower than normal: instead of its full 48A charge, the rate was only 32A:

A few days later, when I went to retrieve some purchases from the car while it was charging, I also saw this alert on the touchscreen:

This struck me as very odd, so I checked everything I could in our electrical system: the Wall Connector, its breaker, other breakers, our Tesla Powerwalls and Gateway, the electric meter, our solar panels and inverter, the utility webpage for a possible brownout —all to no avail. Nonetheless, the slow charging and alert continued. I then decided to drive my car to our community village and plug into its Tesla Destination Chargers. The same slow charging and alert still appeared! Obviously, whatever the problem, it was inside my Model 3’s High Voltage Battery and Drive Unit and could not be blamed on external sources of electricity —despite that misleading alert on the touchscreen.

Now that I knew the problem was in the car itself, I set an appointment and took the car to the Service Center in Las Vegas where we had taken delivery originally.

The Dispute

After returning home, I received a message from the service technicians. They stated that the problem was in my Model 3’s “High Voltage Battery Service Panel.” Specifically, its “Power Conversion System” (PCS) was failing and needed to be replaced. They then claimed that I would have to pay $1,738.18 for a replacement, because Tesla won’t cover repairs in the High Voltage Battery Service Panel under its High Voltage Battery and Drive Unit Warranty, and my car’s general warranty had expired when my odometer crossed the 50K threshold a few weeks previously.

Needless to say, I was shocked. It seems more than obvious to me that the components in the High Voltage Battery Service Panel are an integral part of the High Voltage Battery and Drive Unit to be covered under that warranty. The Service Manager “Alex” called me to discuss the dispute, yet he only reiterated what the service technicians had claimed, and we ended our conversation at an impasse. I then asked him to provide me in writing his position, which he did in a subsequent message: “The battery warranty is specific to the battery. The power conversion system is not covered by the battery warranty.”

My Argument

What remains unclear —and thus in dispute— is an answer to the question: what exactly constitutes “the battery”? Only the 2170 cells? Not the battery’s thermal management system (TMS)? Not its cathodes? Its cables? Its Battery Management System (BMS)? Its High Voltage Battery Service Panel? I purport that Tesla’s High Voltage Battery and Drive Unit Warranty fails to specify what parts and are —or are not— part of the High Voltage Battery and Drive Unit. It simply states that the warranty will “cover the repair or replacement necessary to correct defects in the materials or workmanship of any parts manufactured or supplied by Tesla”:

Here is an illustration borrowed from Tesla’s own “Model 3 Emergency Response Guide,” showing the HV Battery and Drive Unit:

The illustration clearly shows that the battery skateboard, drive train motor, and High Voltage Battery Service Panel constitute an entirely integrated and essential package. More specifically, the service panel feeds, monitors, and regulates electricity from the battery to the drive train; it also feeds, monitors, and regulates electricity to the battery from chargers and regenerative braking from the drive train.

Indeed, what good is a battery without power channeled through the service panel from a charger? And what good is a drive train without power channeled through the service panel from the battery? To claim that the High Voltage Battery Service Panel is not part of the High Voltage Battery and Drive Unit covered under the High Voltage Battery and Drive Unit Warranty makes no sense. Without it, both the battery and the drive train would be completely useless, unable to function as intended, rendering the battery electric vehicle inoperable.

It is relevant to note that, when and if a Tesla Service Center replaces the battery under warranty in a Model 3, this what they install:

Evidently Tesla most certainly does consider the service panel an integral part of “the battery.” I have never heard of an instance when the technicians merely transfer the service panel from an old battery skateboard to a new battery skateboard. They always install the whole kit and caboodle under the High Voltage Battery and Drive Unit Warranty.

Relevant NHTSA Technical Service Bulletin

Tesla is definitely aware that they have a real problem with PCS breakdowns in the service panel. The very year I purchased my Model 3, they filed a Technical Service Bulletin with the NHTSA under the specific Section/Group “16 - HV Battery System.”

It states: “For certain Model 3 vehicles, the power conversion system needs replacement.” The bulletin projects possible dates for the vehicles possibly affected (the earliest, one month after I took delivery), but it also states: “This is a simplified summary of the affected VIN list. Refer to the VIN/Bulletin Tracker or Customer/Vehicle profile to determine applicability of this bulletin for a particular vehicle.” That caveat suggests there are likely more vehicles affected before and after the dates listed, but Tesla failed to inform all Model 3 owners of this potential problem.

Moreover, that Tesla filed this bulletin under the “Section/Group 16 - HV Battery System” attests that they recognize the PCS are, in fact, part of the HV Battery System. Indeed, if Tesla claims otherwise, they would have filed that TSB under “Section/Group 17 - Electrical”:

The Component Affected

What exactly is the problem with the PCS in the High Voltage Battery Service Panel? Below is a photo of a PCS circuit board borrowed from TeslaTap to clarify the issue:

One can see that, toward the middle of the circuit board, there are three sets of blocks, fuses, capacitors, etc. Each one of those sets converts and delivers 16A of AC power to the battery, and thus all three combined deliver 48A —the maximum amount of power that a Model 3 can accept. If one of those sets breaks down, the remaining two can only deliver 32A of power (which has happened in my High Voltage Battery Service Panel). If a second set fails, the last one will deliver only 16A of power. And if all three sets fail… the High Voltage Battery cannot be charged at all from a Level 2 charger.

This would explain why an increasing number of owners are now finding that this integral part of the High Voltage Battery and Drive Unit is starting to fail after 3, 4, 5 years of ownership —in my case after only 3 years and 9 months. Mounting evidence for these failures can be found in the Tesla Owner Forums, such as in this thread, this thread, this thread, this thread, this thread, this thread, and this thread. It is apparent that these battery PCS are of poor design and quality, faulty, prone to break down, and Tesla is trying to pass the hefty expense of these failures on to owners by claiming that the components in the High Voltage Battery Service Panel are not part of the High Voltage Battery and Drive Unit.

Repairs Covered Under the Warranty in Question

Nonetheless, I have learned in those forums that Tesla has, in fact, replaced the PCS in the High Voltage Battery Service Panel under the High Voltage Battery Warranty for other owners. For example, one owner reported (username: "littlD”) that such was the case, and later even shared the text from his invoice:

Another owner (username: “Concestor0”) similarly posted an image of the relevant part of his invoice that clearly states that the Service Center replaced it at zero cost with the description “Pay Type: HV Battery Limited Warranty”:

And more recently, a third owner contacted me to share his invoice showing that Tesla Service had replaced his PCS under the High Voltage Battery and Drive Unit Warranty:


Given the established precedent of those repairs, I object to Tesla’s refusal to complete the repair of my PCS under the very same High Voltage Battery and Drive Unit Warranty. They need to likewise cover the same breakdown in my Model 3 under that warranty. I would also like the company to henceforth do the same for other owners when and if their inadequate PCSs continue to fail. I am convinced that there will be a growing number of such breakdowns in the near future. Consequently, I decided to reject the repair cost quoted by the Service Center, and drove back down to Las Vegas the next day to retrieve my Model 3 with its faulty PCS. I have since filed a complaint for arbitration to settle the dispute according to the “Agreement to Arbitrate” clause in my original Purchase Agreement.

To be brutally honest, I find it ironic that, for several years, Tesla has bragged that the maintenance and repair costs for its vehicles are so low that they make their higher purchase prices more affordable than a gas car over a lifetime of ownership. With the Service Center refusing to cover faulty —and expensive!— PCS under the High Voltage Battery and Drive Unit Warranty, Tesla's braggadocio about such costs now strikes me disingenuous —if not deceptive.

I also must say that, now that I know that the Battery PCS in the penthouse is to blame, I deem it disingenous —if not purposely misleading— for Tesla to have programmed the particular alert up above to appear on the touchscreen. After all, when the car detects other problems, such as a weak 12V battery, an alert specifically advises the owner to contact a Service Center to replace it. Not so when it detects this particular problem: the diagnostic software tries to point the finger at “poor grid quality” instead.

Finally, I wish to reiterate that, with the exception of this PCS breakdown, I have been pleased with my Model 3. As a very active EV supporter, I have constantly promoted and recommended Tesla for several years, as demonstrated in my posts on ownership, advocacy, roadtrips, and accessories. I sincerely hope that Tesla will do right by its owners who are now facing these premature breakdowns and cover the repairs under its High Voltage Battery and Drive Unit warranty.