How can I keep my Tesla’s battery charged over the winter?

John Paul, AAA Northeast's Car Doctor, answers a question from a reader whose Tesla won't be used over the winter.

Unsold 2019 Model 3 sedans sits at a Tesla dealership in Littleton, Colo.
2019 Model 3 sedans sit at a Tesla dealership in Littleton, Colo. –AP Photo/David Zalubowski, File

Q. I read an answer to a question about someone storing a RAV4 hybrid, and you gave an answer about keeping the 12-volt battery charged. I have a Tesla Model 3, and it will sit for several months this winter. Will a float-style charger compensate for the parasitic drain for such a large battery?

A. Similar to a hybrid, your Tesla uses a 12-volt battery in addition to the traction batteries. The biggest issue is that Tesla provides very little technical information. My assumption is, if the main battery is fully charged and plugged in, even at 120 volts, the on-board DC converter should keep the 12-volt battery charged. 

John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE certified master technician. Email your car question to