How to Make Your Car Battery Last Longer
Our auto experts advise on how to keep your car powered up
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You try to turn on your car, and it just won’t start. Maybe the dashboard doesn’t even light up. A likely cause: The 12-volt battery is dead.
All cars lose a little battery power when parked. If you drive the car regularly, its electrical system will charge the battery back up. But if your battery dies after being parked for only a few days, you may have a serious problem that could eventually leave you stranded.
Don't Let the Car Sit
Driving is better than idling to top off the battery. How long you can wait between drives depends on the car, but in general, driving it at least 20 minutes roughly every two weeks should keep the battery functional. If you can’t manage that, find and disconnect the negative battery cable—the black wire. This keeps systems in the car from drawing power while it’s off.
Expert tip: Buy a trickle charger (around $30 and up), which keeps the battery charged from a wall outlet.
Best Car Batteries From CR's Tests
See our review of car batteries from DieHard, Interstate, and other popular brands to find out how long they’ll last.
Mind the Accessories
Don’t stay in “accessory mode” for long. That’s when the radio or heater are on but the engine stays off—often activated by pushing the stop/start button without your foot on the brake. In this mode, the car is using battery power without recharging.
Expert tip: Add-ons such as a dash cam or mobile phone charger can drain the battery faster. “Make sure these devices are unplugged when the car is parked,” Crossen says. “It’s not enough to just turn their power off.”
Lock It Up
Even if your car sits in a secure garage, lock the doors. Many cars leave some systems powered when left unlocked to stay ready for someone to get in and drive away. Locking the car minimizes the power that is drawn.
Expert tip: Modern proximity keys—which automatically unlock the car when you approach—are convenient. But store them far enough away that they don’t accidentally wake up the car. “A hook on your garage wall could be too close,” Crossen says.
Maintenance Is Key
“Check that the cable connections are tight, clean, and free of corrosion, which often looks like fuzzy, green and white buildup,” Crossen says. (If you don’t want to do this yourself, ask your mechanic.) Periodic testing can also tell you when the battery is due for replacement before it completely fails. “Test it twice a year at a minimum,” Crossen says.
Expert tip: Many shops test the battery when cars come in for service, so check your paperwork for a slip with the inspection results.
Just in Case
Even well-maintained batteries can fail, so it’s good to have a backup plan. The easiest option is a service membership like AAA, which will send a service technician to jump-start the car.
Expert tip: Buy a jump-starter—a small rechargeable battery that clamps to the car battery (around $50 and up). “Modern jump packs are safer than jumper cables,” Crossen says. “Many have electronics to protect against mistakes like connecting the leads backward.”
Best Car Batteries
Below, we highlight the best-performing car batteries in several popular categories (Group 24, Group 35, Group 48, and Group 65). See our complete car battery ratings.
More on Car Batteries
Editor’s Note: This article also appeared in the January/February 2026 issue of Consumer Reports magazine.
