How to Change a Car Battery

Updated: Mar. 21, 2024

Here's what you need to know about car batteries and how to change them.

How Long Do Car Batteries Last?

A car battery typically lasts five years but it can be as few as two years depending upon how you drive and the number of accessories you use in your car. Batteries tend to last longer in colder climates because warm climates increase damage because of sulfation and water loss. Here’s how to double the life of your car battery.

hydrometer tests car batteryFamily Handyman

How To Check a Car Battery

Test the electrolyte in each cell. Squeeze the ball and draw the solution into the tester. Carefully hold the tester level and write down the reading. Squirt the solution back into the same cell. The testers are calibrated assuming a battery is at 80 degrees F. Add .04 to each reading for every 10 degrees above 80 and subtract .04 for every 10 degrees below. If you get a cell reading that differs from the others by .05 or more, replace the battery. A fully charged battery should have a reading of 1.265 or higher. If all the readings show fair or low (1.200 is low) but are consistent, recharge the battery.

If you have a no-maintenance battery, check to see if you have a green dot in the sight glass/charge indicator. Green means the battery is good. If it’s dark, it needs recharging. If it’s yellow or has no color at all, (inspect carefully and use a flashlight), replace the battery.

How To Change a Car Battery

Changing a car battery requires just a few tools, usually a wrench to loosen the cables, gloves and some petroleum jelly to spread on the terminal before installing the new battery.

how to replace a car batteryFamily Handyman

How to Remove a Car Battery

  • Remove the battery hold-down clamp
  • Disconnect the negative cable first with a wrench
  • Disconnect the positive cable
  • Lift the battery out by the strap, but be careful of any leaks because battery acid is dangerous

Removing a car batteryFamily Handyman

How to Install a Car Battery

  • Check to see if your new battery needs charging before using it. Most batteries are at least 75 percent charged when you buy them
  • Place the new battery in place
  • Connect the hold-down clamp
  • Smear petroleum jelly on the battery terminals, it will help slow corrosion. If your terminals are too corroded already, here’s how to replace car battery terminals.
  • Attach the positive terminal first and then the negative terminal

How to Recycle a Car Battery

You can typically return your old car battery to the place you purchased your new battery. You typically receive a credit for bringing back the old battery. Auto parts stores will also accept old batteries. You can also contact your local waste center or recycling center to see if they’ll accept old batteries.

Learn more about car battery care and the signs of when to replace your car battery.