How to care for your car battery

The last thing you need is a car that won’t start because the battery is dead. You can avoid that expensive service or tow charge (and the worry of being stranded!) by carrying out a 10-minute seasonal battery check along with a few maintenance tips.

Clean the cables

First clean the top of the battery and any corrosion from the cables using a tablespoon of baking soda, a cup of water and a nonmetallic brush. Flush with cool water. Now disconnect the cables, starting with the negative one to prevent your wrenches from arcing on a nearby ground. Loosen the battery cable clamp bolts and gently give them a twist. Use a cable puller if they’re stuck. Never pry on the battery posts. If you have a side post terminal use a 5/16-in. box wrench to loosen the cables. With the cables removed, further clean off the corrosion around the battery terminals and cables with a post cleaner.

Check the level of the electrolyte

If the battery needs water, use clean, distilled water and don’t over fill the cells. Gently pry off the covers of the battery cells. The water and acid mixture in the battery (electrolyte) should be about 1/2 in. deep or to the bottom of the fill hole. If it needs water, use clean distilled water, being careful not to overfill the cells, and then inspect the battery case for cracks. If you find a crack, replace the battery. If you added water, let the water mix with the electrolyte for a few hours before the next step.

Check the condition and charge of the battery

Test the electrolyte in each cell with a hydrometer. To 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.

To drop in the new battery, first remove the cables

Remove your battery hold-down clamp. Disconnect the negative cable first, then the positive. Note: Always replace the battery with one that has a higher rating than the original.

Always wear eye protection and rubber gloves when working on batteries, and never smoke around them!

Replace the battery

Use the heavy-duty strap to carefully lift out the old battery

Tie a heavy-duty strap to the ears on the side of the battery and gently lift it out. Be careful; battery acid is dangerous. Don’t drop it. Once the battery is out, clean the battery tray and replace it if it’s badly corroded. Batteries are heavy and need solid support!

Reinstall the clamp and cables

Carefully lift the new battery into place. Connect the hold-down clamp, then connect the cable to the positive terminal first and the negative last (for negative ground systems). Smear a little petroleum jelly onto the terminal before fastening the cable clamps to the posts. The grease will help slow corrosion. Most batteries are at least 75 percent charged when you buy them and should be ready for you to start your car and drive. Check with your supplier to see if your new battery needs charging before you use it.

Telltale signs of a low or failing battery

Your headlights look dim at idle and then brighten when you rev the engine.

The starter turns slowly, barely starting the car. But you may have alternator wiring problems that prevent the battery from fully charging. If that’s the case, schedule a service appointment. Check your fan belt. If it’s loose, frayed, cracked or glazed, have it serviced or replaced.

A low battery can also be caused by frequent short trips, as well as too many accessories left on or added.

Look for a purchase date chart on the battery (it may be handwritten). The battery case will also have a decal stating its expected life, such as 60 or 84 months. If it’s near the end of this expected service life, replace it.