Battery maintenance

Difficulty in starting accounts for almost half of the service calls that the American Automobile Association (AAA) makes each year.

A survey by Champion Spark Plug Company indicated that roughly one third of all vehicles experienced one "can't start" condition in a given year.

When a vehicle won't start, most people blame the battery when, in fact, it may be that the battery has run down in a futile attempt to start a vehicle with other problems.

Battery output is affected by ambient temperatures; the battery becomes less efficient at low temperatures, while the power required to start the engine becomes greater. All this means that it pays to keep your battery in good shape, so that power is there when it's needed.

General maintenance

A battery that is not sealed must be checked periodically for electrolyte level. You cannot add water to a sealed maintenance-free battery (though not all maintenance-free batteries are sealed); however, a sealed battery must also be checked for proper electrolyte level, as indicated by the color of the built-in hydrometer "eye."

Always keep the battery cables and terminals free of corrosion. Check these components about every three months, or 3000 miles (4800 km). Refer to the removal, installation and cleaning procedures outlined in this section.

Keep the top of the battery clean, as a film of dirt can help completely discharge a battery that is not used for long periods. A solution of baking soda and water may be used for cleaning, but be careful to flush this off with clear water. DO NOT let any of the solution into the filler holes on non-sealed batteries. Baking soda neutralizes battery acid and will de-activate a battery cell.

Batteries in vehicles which are not operated on a regular basis can fall victim to parasitic loads (small current drains which are constantly drawing current from the battery). Normal parasitic loads may drain a battery on a vehicle that is in storage and not used for 6-8 weeks. Vehicles that have additional accessories such as a cellular telephone, an alarm system or other devices that increase parasitic load may discharge a battery sooner. If the vehicle is to be stored for 6-8 weeks in a secure area and the alarm system, if present, is not necessary, the negative battery cable should be disconnected at the onset of storage to protect the battery charge.

Remember that constantly discharging and recharging will shorten battery life. Take care not to allow a battery to be needlessly discharged.

Battery fluid
See Figure 19

Check the battery electrolyte level at least once a month, or more often in hot weather or during periods of extended vehicle operation. On non-sealed batteries, the level can be checked either through the case on translucent batteries or by removing the cell caps on opaque-case types. The electrolyte level in each cell should be kept filled to the split ring inside each cell, or the line marked on the outside of the case.

If the level is low, add only distilled water through the opening until the level is correct. Each cell is separate from the others, so each must be checked and filled individually. Distilled water should be used, because the chemicals and minerals found in most drinking water are harmful to the battery and could significantly shorten its life.

Figure 19 Add only distilled water to prolong battery life.

If water is added in freezing weather, the vehicle should be driven several miles to allow the water to mix with the electrolyte. Otherwise, the battery could freeze.

Battery electrolyte contains sulfuric acid. If you should splash any on your skin or in your eyes, flush the affected area with plenty of clear water. If it lands in your eyes, get medical help immediately.

Checking the charge on maintenance-free batteries
See Figure 23 and 24

Although some maintenance-free batteries have removable cell caps for access to the electrolyte, the electrolyte condition and level on all sealed maintenance-free batteries must be checked using the built-in hydrometer "eye." The exact type of eye varies between battery manufacturers, but most apply a sticker to the battery itself explaining the possible readings. When in doubt, refer to the battery manufacturer's instructions to interpret battery condition using the built-in hydrometer.

Although the readings from built-in hydrometers found in sealed batteries may vary, a green eye usually indicates a properly charged battery with sufficient fluid level. A dark eye is normally an indicator of a battery with sufficient fluid, but one that may be low in charge. In addition, a light or yellow eye is usually an indication that electrolyte supply has dropped below the necessary level for battery (and hydrometer) operation. In this last case, sealed batteries with an insufficient electrolyte level must usually be discarded.

Figure 23 A typical sealed (maintenance-free) battery with a built-in hydrometer. Note that the hydrometer eye may vary between manufacturers; always refer to the battery's label.

Figure 24 The colder the weather, the healthier the battery has to be to provide sufficient starting power.

Your car's battery will perform efficiently if maintained at these intervals.
1. Check electrolyte level/add water.     Check state of charge.	Every month or 1000 miles
2. Check/clean terminals and cables.	Every 3 months or 3000 miles
3. Tighten battery hold-downs.	As needed

Battery cables don't go bad very often, but like anything else, they can wear out. If the cables on your car are cracked, frayed or broken, they should be replaced.

Continue to page 1 of The electrical system: Batteries and cables

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