See Figure 1
Periodically, clean the top of the battery with a solution of baking soda and water using a stiff bristle brush. This will neutralize acid and clean corrosion from the terminals and battery case, which will keep the acid from damaging the battery and will allow a better electrical connection between the battery cables and the battery. Since this solution neutralizes acid, make sure it does not get into the battery itself.
If any acid has spilled onto the battery tray, clean this area in the same way. If paint has been removed from the tray, wire brush the area and paint it with a rust-resistant paint.
Remove the cable ends, clean the cable end clamps and battery posts, and reconnect and tighten the clamps. Apply a thin coat of petroleum jelly to the terminals, which will help to retard corrosion. The terminals can be cleaned with a wire brush or with an inexpensive terminal cleaner designed for this purpose.
Some batteries were equipped with a felt terminal washer. This should be saturated with engine oil approximately every year. This will also help to retard corrosion.
See Figure 2
The factory-installed battery is a maintenance-free type on all the Mitsubishi models covered by this manual. That means that you'll never have to remove caps (there aren't any) to add water. But a yearly inspection and cleaning of the battery, connections, and battery mountings is recommended to guarantee maximum reliability.
On a sealed maintenance-free sealed battery a built-in hydrometer or eye is used for checking the fluid level and specific gravity readings. If your battery is equipped with an eye, use it for checking the condition of the battery by determining the color of the eye. Refer to the battery case or owner manual for further instructions. Replacement batteries could be either sealed maintenance-free or a non-sealed type.
Many replacement batteries are of the maintenance free type. For these batteries, follow the procedures described earlier. If the replacement battery you have purchased is not a maintenance free type, follow these easy procedures.
Check the battery fluid level at least once a month, more often in hot weather or during extended periods of travel. The electrolyte level should be up to the bottom of the split ring in each cell. If the level is low, add water. Distilled water is best for this purpose, but ordinary tap water can be used in a pinch.
At least once a year, check the specific gravity of the battery with a hydrometer. It should be between 1.20-1.26 on the hydrometer's scale. Most importantly, all the cells should read approximately the same. If one or more cells read significantly lower than the others, it's an indication that these low cells are going bad. Replace the battery.
If water is added during freezing weather, the vehicle should be driven several miles to allow the electrolyte and water to mix. Otherwise the battery could freeze.Filling the Battery
Batteries should be checked for proper electrolyte level at least once a month or more frequently. Keep a close eye on any cell or cells that are unusually low or seem to constantly need water-this may indicate a battery on its last legs, a leak, or a problem with the charging system.
Top up each cell to the bottom of the split ring, or, if the battery has no split ring, about 3 / 8 in. (9.5mm) above the tops of the plates. Use distilled water where available, or ordinary tap water, if the water in your area isn't too hard. Hard water contains minerals that may slowly damage the plates of your battery.
CABLES AND CLAMPS
See Figures 3 and 4
Once year, the battery terminal posts and the cable clamps should be cleaned. Loosen the clamp bolts (you may have to brush off any corrosion with a baking soda and water solution if they are really messy) and remove the cables, negative cable first. On batteries with posts on top, the use of a battery clamp puller is recommended. It is easy to break off a battery terminal if a clamp gets stuck without the puller. These pullers are inexpensive and available in most auto parts stores. Side terminal battery cables are secured with a bolt.
The best tool for battery clamp and terminal maintenance is a battery terminal brush. This inexpensive tool has a female ended wire brush for cleaning terminals, and a male ended wire brush inside for cleaning the insides of battery clamps. When using this tool, make sure you get both the terminal posts and the insides of the clamps nice and shiny. Any oxidation, corrosion or foreign material will prevent a sound electrical connection and inhibit starting or charging. If your battery has side terminals, there is also a cleaning tool available for these.
Before installing the cables, remove the battery hold-down clamp or strap and remove the battery. Inspect the battery casing for leaks or cracks (which unfortunately can only be fixed by buying a new battery). Check the battery tray, wash it off with warm soapy water, rinse and dry. Any rust on the tray should be sanded away, and the tray given at least two coats of a quality anti-rust paint. Replace the battery, and install the hold-down clamp or strap, but do not overtighten.
Reinstall your clean battery cables, negative cable last. Tighten the cables on the terminal posts snugly; do not overtighten. Wipe a thin coat of petroleum jelly or grease all over the outside of the clamps. This will help to inhibit corrosion.
Finally, check the battery cables themselves. If the insulation of the cables is cracked or broken, or if the ends are frayed, replace the cable with a new cable of the same length or gauge.
CHARGING AND REPLACEMENT
Charging a battery is best done by the slow charging method (often called trickle charging), with a low amperage charger. Quick charging a battery can actually "cook" the battery, damaging the plates inside and decreasing the life of the battery drastically. Any charging should be done in a well ventilated area away from the possibility of sparks or flame. The cell caps (not found on maintenance-free batteries) should be unscrewed from their cells, but not removed.
If the battery must be quick-charged, check the cell voltages and the color of the electrolyte a few minutes after the charge is started. If cell voltages are not uniform or if the electrolyte is discolored with brown sediment, stop the quick charging in favor of a trickle charge. A common indicator of an overcharged battery is the frequent need to add water to the battery.
When it becomes necessary to replace the battery, be sure to select a new battery with a cold cranking power rating equal to or greater than the battery originally installed. Deterioration, embrittlement and just plain aging of the battery cables, starter motor and associated wires makes the battery's job all the more difficult in successive years. The slow increase in electrical resistance over time makes it prudent to install a new battery with a greater capacity than the old. Details on battery removal and installation are covered in Engine & Engine Rebuilding .