Get a charge from your battery

CAR batteries are more reliable than ever, but they still need to be checked and maintained regularly. Here's some battery savvy. Why they fail Battery problems can be traced to old age, loose or corroded terminals, trouble with the starting and charging system, or an out-of-tune engine.

Cold weather is especially tough on batteries. Low temperatures weaken them by slowing the chemical reaction that produces electricity. That's why even a good battery functions at no more than 65 percent efficiency when the temperature drops below freezing. At zero, it may drop below 40 percent. Checking the charge

As part of your auto-maintenance routine, and especially before winter or a long trip, check the battery charge yourself or have the battery checked out by a mechanic.

If you own one of the new maintenance-free batteries with a built-in hydrometer, you can check the charge yourself by looking at an indicator light atop the battery. When the battery is adequately charged, the indicator shows green. When it needs charging, it shows black. A yellow or light color means the battery should be replaced.

If your car has a conventional battery (with vent caps), you can buy a hydrometer to test the battery charge yourself, by drawing fluid from the battery cells and consulting the scales on the instrument.

Other telltale signs of a weak battery are sluggish starting, dim lights when the engine isn't running, and a slower-than-normal turn signal when the ignition switch is in the ``accessory'' position.

Also check for frayed battery cables, loose clamps, and corrosion around the battery terminals. Remove corrosion with a stiff wire brush and a baking-soda-and-water solution. If the battery isn't the factory-sealed type, also check the fluid level in each cell. If it's low, fill with distilled water. Buying a new one

If your battery is more than 30 months old, has been in use for more than 30,000 miles, or is showing signs of weakness, consider buying a new one. Recharging is only a temporary solution.

While more expensive than conventional batteries, low maintenance or ``maintenance free'' batteries are worthwhile if you plan to keep your car two or more years. Under normal conditions, maintenance-free batteries should never require water and should last four to five years.

If you choose a conventional battery, note the battery's cold-power rating. It should be at least equal to your engine's cubic-inch displacement to power your car adequately. If your car has a 350-cubic-inch engine, for example, select a battery with a cold-power rating of 350 or greater. Consider a heavy-duty battery if you live in a cold area or do a lot of stop-and-go driving. Safety tips

Batteries produce explosive gases, contain corrosive acid, and supply high levels of electrical current, which can burn. When working near a battery, shield your eyes and avoid leaning over the battery as much as possible. Don't expose the battery to open flames or sparks, and don't allow battery acid to contact the eyes or skin. Flush any contacted area with water immediately.

Giving your car a kick JUMP-STARTING borrows energy from a good battery to start a car with a run-down battery. But careless use of booster cables to jump-start a disabled car can endanger you and the vehicle. If you can't wait for professional service, keep in mind these procedures: Follow the jump-starting directions given in the owner's manual for the disabled vehicle. Make sure the voltages of the two batteries are the same - a 12-volt system to start a 12-volt system; a 6-volt system to start a 6-volt system. Never try to jump-start a frozen battery. Pockets of hydrogen gas may have formed, and the battery could explode when the jumper cable is attached. Connect the positive terminal of the good battery to the positive terminal of the run-down battery; then connect the negative terminal of the good battery to the engine block of the stalled car to ensure a good ground. Don't push or tow a vehicle to start it. Besides increasing the risk of accidents, this method may damage the catalytic converter and other components of the car.