Best not to use your Tesla like an F-150

While Ford Motor Co. was encouraging dealerships in Texas to loan out F-150s with built-in generators during recent power outages, some Tesla owners learned that using the battery in a similar fashion could result in an unexpected repair bill.

One Tesla owner posted instructions and photos in a Facebook group showing how to connect the battery to lights and appliances through a store-bought inverter. But a few days later, the owner followed up to say that his car's 12-volt battery had gone bad as a result and that Tesla was making him pay for a replacement.

"They are replacing the 12v not under warranty because they looked up this Facebook post and used that to determine I've violated the use of the car," the owner wrote in a widely shared post. Another Tesla fan who shared the post wrote: "It pains me to post this, but if you used the awesome battery of your Tesla car to keep lights on in time of need, DO NOT brag about it on social media! It's a warranty-voiding activity."

Tesla's warranty specifically excludes damage or malfunctions caused by "using the vehicle as a stationary power source."