Avoid an expensive service or tow charge (and the worry of being stranded!) by keeping your car battery working at peak performance. This article will show you how to perform a simple step-by-step 10-minute seasonal battery check-up so you know whether your battery is performing well. This article will also explain how to replace your battery if it's failing, so you're not left stranded out in the middle of nowhere with a car that won't start.
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.
In addition to a set of wrenches, you'll only need a post cleaner or side terminal, a hydrometer and a cable puller, all available at auto parts stores. Keep in mind that you can skip the battery service if you make sure the mechanic does it during periodic servicing, but you'll want to keep up with the regular maintenance.
Clean corrosion from the top of the battery first and then clean corrosion from around the battery cables with a post cleaner.
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. (We discuss what to if you have a no-maintenance sealed battery later in this step.) 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. (You may need to reconnect the battery to maintain your memory functions.)
To test the electrolyte in each cell, squeeze the ball on the hydrometer and draw the solution into the tester. Hold the test level, record the reading and squirt the solution back into the cell.
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.
Disconnect the negative cable first and then the positive
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.
Use the heavy-duty strap to carefully lift out the old battery
Connect the hold-down clamp before connecting the cable to the terminals
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.
You've emptied the gas, sealed the exhaust and prepared the engine for seasonal storage. But before you throw the tarp over your boat or roadster for the long winter sleep, think about how you're going to care for the battery.
Batteries lose their charge when they sit idle, and when that happens, you could wind up with a worthless battery in the spring. To keep batteries healthy, they should be charged every six weeks. But leaving a standard battery charger connected for the whole season isn't a good idea—that will overcharge the battery and shorten its life. Instead, invest in a “battery maintainer.”
Battery maintainers are designed to be left on for the entire off-season. They monitor battery voltage and automatically adjust the charge to avoid under- and overcharging.
Battery charger/maintainers and quick-release terminals are available at most auto parts stores or online.
A low battery can also be caused by: