Tesla continues to impress with its vehicle systems engineering and overall customer experience, as demonstrated by a recent experience with the 12V battery replacement in a 2019 Tesla Model 3. While some may assume that electric vehicles (EVs) do not require a separate 12V battery due to their large battery packs, this assumption is incorrect. The 12V battery powers various electrical components in the vehicle, including lights, wipers, door mechanisms, and the infotainment system.
The author received a notification from the Tesla app on a Sunday morning, alerting them to replace the 12V battery soon. They immediately booked an appointment through the app for the following afternoon with a mobile technician. The convenience of scheduling the service without needing to check the car or speak to anyone impressed the author. This stands in contrast to other vehicles where 12V battery issues may only become apparent when attempting to drive.
Despite the need for a battery replacement, the Tesla Model 3 continued to function normally. The author had experienced situations in old petrol cars where a flat battery left them stranded, and even with another brand of EV that required a jump start when the 12V battery was low. The Model 3 displayed warnings related to the 12V battery on the screen, but there were no issues starting and driving the vehicle.
The car manual revealed that the Model 3 relies more heavily on the DC to DC converter in such situations. This converter, which performs a similar function to an alternator in an internal combustion car, keeps the 12V battery charged by utilizing the main high voltage battery pack. Unlike an alternator, the DC to DC converter can operate at any time, as it does not depend on an engine running to generate electricity.
Tesla has taken steps to eliminate battery failure by introducing a new lithium-ion low voltage battery in all new cars since the start of 2022. These batteries are designed to last the life of the vehicle and offer a superior solution compared to the previous lead-acid 12V batteries. However, the newer batteries cannot be retrofitted into older Tesla vehicles.
The Tesla technician arrived on the scheduled appointment and completed the 12V battery swap in around 15 minutes. According to the technician, the expected lifespan of a lead-acid 12V battery is approximately 3 years, and there is roughly a week to replace the battery after the service message appears.
This experience highlights the strength of Tesla’s vehicle systems engineering and customer experience. While the convenience and efficiency may vary for those located outside major cities, Tesla owners are provided with ample time to source replacement batteries and even have the option to perform the replacement themselves with guidance from the owner’s manual. To learn more about EV electrical systems, the author recommends checking out the Ingineerix channel on YouTube for in-depth explanations and demonstrations.