Usage:
- SUPPLEMENT: 04/00/89
TRUCK ENGINE NEWS, MARCH 1989, PAGE 5, "Preventive Maintenance For Batteries." In Step 1 it should read, "1 1/2 cups of baking soda per one gallon of water (or, 475 cm3 of baking soda per 5 L of water). (112 cups is NOT correct.)
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The battery is often overlooked in many preventive maintenance programs. This is unfortunate because, with a little care, battery life can be substantially extended. Caterpillar® suggests some relatively simple steps to ensure greater reliability and longer battery life.
The most important is to make sure electrolyte levels are checked at appropriate intervals. Standard, or conventional, batteries should be checked every 100 hours. Electrolyte levels should be checked in low maintenance batteries at each 250-hour interval. No acid level check is required or can be performed on the maintenance-free design.
If the electrolyte level is low, add only distilled water to keep possible contaminants out of the battery. While checking the electrolyte make a few other visual inspections:
1. Is there any indication of damage or corrosion on the battery term inals, the battery box or wiring? If so, clean or repla ce the necessary components. Cleaning can best be done with a solution of baking soda and water 12 cups baking soda per gallon of water). Visual inspection could also alert you to the possibility of a cracked battery which could only be identified by corrosion in the battery tray.
2. Are the hold-downs tightened correctly? Vibration will destroy a battery faster than anything else.
3. Is there debris under the battery? This must be removed when hold-downs are tightened as this can cause holes to be worn in the case and result in loss of electrolyte.
4. Are all vent caps correctly in place? Loss of vent caps can pose a potential hazard and permit contamination of the battery.
5. Are the alternator belts tight? If not, the battery will not charge correctly and poor performance will result.
6. What is the alternator output voltage? Use a voltmeter to check it. This will identify both low charging voltages due to loose fan belt and also high charging voltages which can damage a battery. Alternator charging voltage should be 13.5 to 14.5 volts for a 12 volt system and 27.0 to 29.0 for a 24 volt system.
While the maintenance-free batteries do not require electrolyte checks, do steps 1, 2, 3, 5 and 6 every 1,000 hours for maximum battery life.
Another important factor in prolonging battery life is proper storage. Batteries are perishable items and can lose efficiency when not in use. Batteries discharge faster in high temperatures so they should be stored in the coolest place possible. Small, constant electrical current loads like brushless alternators, electronics, clocks, etc., can run a battery down when not in use. If a machine will not be used for 30 days or more, open the disconnect switch or remove the ground (negative) cable from the battery.
The next step is to check the batteries' state of charge. This is called checking the open-circuit voltage. Use a digital volt meter such as 6V7070 Multimeter. An analog meter (moving needle type) is not accurate enough for battery use. Set the voltmeter on the 20-volt DC state and touch the probes to the battery terminals with the engine off. A reading of 12.40 or more (for a 12 volt battery) means the battery is charged sufficiently. Any reading less than 12.40 means the battery needs charging.
If the battery has been recently charged, the surface charge must be removed before making this test. To remove the surface charge, crank the engine for about 5 seconds with the fuel shut off, or turn on the headlights for about one minute. The open circuit voltage can then be accurately checked.
If the battery is below 12.40 open circuit voltage, then it should be charged. The slow charge method for charging a battery will provide the best results. The battery should be charged at the manufacturer's recommended rate or 3% of the Cold Cranking Amps (CCA) rating. For example, Caterpillar's 8D battery is rated at 1250 CCA, thus the charge rate should be approximately 37 amps.
The charging voltage should never exceed 16 volts. Too much voltage will cause serious damage to the battery. Charge time could be as little as a few hours for a battery near 12.40 open-circuit voltage to approximately 8 hours for a fully discharged battery.
For more complete information on charging a battery, see either Special Instruction, SEHS9014, "Battery Charging Rate/Time Tables", or SEHS7633 " Battery Test Procedure".
To assure the battery will function correctly, it should be load-tested. To do this, see Special Instruction SEHS7633 "Battery Test Procedure".
Preventive maintenance and appropriate checking and charging can increase battery life. There are two most significant problems with batteries brought in for service: they have been discharged or they have been subjected to abuse (for example: lack of water, loose hold-downs, etc.). Regular preventive maintenance can reduce the possibility of throwing away a good battery. You can obtain more information on batteries and assistance in battery testing from any Caterpillar dealer.