Why do EVs have 12V batteries?


Just like a gas car, an electric vehicle has a 12-volt battery to power accessories and security functions while the car is parked.

This is true from Chevrolet to Tesla, from Hyundai to Rivian. 12-volt systems have remained popular due to their minimal wire gauge requirements and the fact that the same parts can be used for gas and electric cars. 

At the end of the day, an EV is still a car. Until automakers decide to change the way accessories are powered, cars will still have 12V systems. However, some automakers, such as Tesla, are improving on the system by using lithium ion 12V batteries.

Do Teslas Have 12V?

In the Tesla Model 3/Y, there is a unique procedure for jumping or removing the 12V battery when it dies. This procedure may not be known to tow companies or individuals who need to access a dead battery. In brief, there is a port on the front of the car that can opened to reveal a wiring harness. Hook that up to a 9V battery (or a 12V battery source) and the frunk will pop open - if and only if the 12V battery is completely dead. Once open, you can then remove the access panel that normally covers the 12V battery. Consult your Tesla owner’s manual for more information. 

What else should you know about the Tesla 12V battery? As of 2022, Tesla is shipping cars with lithium 12V batteries which should last years longer than the SLA batteries previously equipped on Tesla cars. Other manufacturers are following suit, so be sure to check your vehicle’s specs so you are aware of the 12V battery replacement schedule. Then, set a calendar alert to preempt needing to replace one in an emergency.


Overall, unless your manufacturer has issued a recall about 12V batteries, you shouldn't have much to worry about for the first several years of ownership. That is, unless you leave a door open or accessories on overnight. The biggest takeaway is to know how to unlock and/or jump start your car if that battery does need servicing. Your vehicle’s user manual will be the place to check.