All Isuzu vehicles have a "maintenance free" battery as standard equipment, eliminating the need for fluid level checks and the possibility of specific gravity tests. Nevertheless, the battery does require some attention.
Once a year, the battery terminals and the cable clamps should be cleaned. Remove the side terminal bolts and the cables, negative cable first. Clean the cable clamps and the battery terminals with a wire brush until all corrosion, grease, etc. is removed and the metal is shiny. It is especially important to clean the inside of the clamp thoroughly, since a small deposit of foreign material or oxidation there will prevent a sound electrical connection and inhibit either starting or charging. Special tools are available for cleaning the side terminal clamps and terminals.
Before installing the cables, loosen the battery hold-down clamp, remove the battery, and check the battery tray. Clear it of any debris and check it for soundness. Rust should be wire-brushed away, and the metal given a coat of anti-rust paint. Replace the battery and tighten the hold-down clamp securely, but be careful not to overtighten, which will crack the battery case.
After the clamps and terminals are clean, reinstall the cables, negative cable last. Give the clamps and terminals a thin external coat of grease after installation, to retard corrosion.
Check the cables at the same time that the terminals are cleaned. If the cable insulation is cracked or broken, or if the ends are frayed, the cable should be replaced with a new cable of the same length and gauge.
Maintenance free batteries do not require normal attention as far as fluid level checks are concerned. However, the terminals require periodic cleaning, which should be performed at least once a year.
The sealed top battery cannot be checked for charge in the normal manner, since there is no provision for access to the electrolyte. To check the condition of the battery:
- If the indicator eye on top of the battery is dark, the battery has enough fluid. If the eye is light, the electrolyte fluid is too low and the battery must be replaced.
- If a green dot appears in the middle of the eye, the battery is sufficiently charged. Proceed to Step 4. If no green dot is visible, charge the battery as in Step 3.
- Charge the battery at this rate:
- Connect a battery load tester and a voltmeter across the battery terminals (the battery cables should be disconnected from the battery). Apply a 300 amp load to the battery for 15 seconds to remove the surface charge. Remove the load.
- Wait 15 seconds to allow the battery to recover. Apply the appropriate test load, as specified in the load test chart in this section.
- Apply the load for 15 seconds while reading the voltage. Disconnect the load.
- Check the results against the following chart. If the battery voltage is at or above the specified voltage for the temperature listed, the battery is good. If the voltage falls below what's listed, the battery should be replaced.