If you’re new to electric vehicles—or are starting to research options for an upcoming purchase—you may not know that in addition to the high-voltage battery pack that supplies power to the motor, they also use the same 12-volt batteries that gas-powered vehicles do. And, yes, these 12-volt batteries can lose their charge and prevent the car from starting.
But the good news is, they can also be jump started—including with the help of a gas-powered vehicle. In an article for Kelley Blue Book, Chris Hardesty breaks down the whole process. Here’s what to know.
Safety concerns when jump-starting a battery in an electric vehicle
Before getting into how to do the jump-start, we wanted to point out a few of the safety concerns Hardesty brings up in the article:
While it’s possible to jump the 12-volt battery in an electric vehicle, never attempt to jump-start their high-voltage lithium-ion batteries.
Do not use an electric vehicle (EV) to jump-start another 12-volt battery. “The EV’s charging points are for jump-starting the car itself and not for assisting another vehicle with a jump-start,” Hardesty writes.
The vehicle giving the electric vehicle a jump-start must have a 12-volt battery with a negative ground system—which, Hardesty says, is typical with gas-powered cars.
The instructions below provide a general overview of how to jump-start electric vehicle batteries, but be sure to check the owner’s manual first, in case that particular make/model needs any special treatment.
You can also use a portable jump-start device on an electric vehicle’s 12-volt battery.
How to jump-start a 12-volt battery in an electric vehicle
In his article, Hardesty provides the following instructions for jump-starting a discharged 12-volt battery in an electric vehicle:
Position the cars
. Place the two vehicles, the EV and the vehicle with a good battery, near each other so they do not touch.
Turn on the brake
. Shift into park and put on the parking brake.
Switch off everything
. Check and make sure you turn off the lights and accessories in both vehicles.
Connect positive clamps
. Now you’re ready to connect one end of the red positive (+) cable to the discharged battery’s positive (+) terminal. When done, attach the other end of the positive (+) jumper cable to the positive (+) terminal of the booster vehicle battery.
Attach negative clamps
. Next, place one end of the black negative (–) cable to the good battery’s negative (–) terminal. Now, connect the negative (-) jumper cable to the negative (-) grounding point for the discharged battery.
Check
. Ensure that the booster cables are away from any moving parts and that the clamps have good metal-to-metal contact with the battery terminals and charging points.
Start the car of the donation vehicle
. Take the vehicle with the good battery and start the car.
Get the EV started
. Finally, try to start the EV with the dead battery.
Read Hardesty’s full article for additional tips, including how to remove the jumper cables.