C15 and C18 – Charging System – Test

The condition of charge in the battery at each regular inspection will show if the charging system is operating correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed. A large amount of water would be more than 1 oz of water per a cell per a week or per every 100 service hours.

Testing of the charging system components on the engine is preferred, including the wiring and other components that are a permanent part of the system. Off-engine testing or bench testing of the operation of the charging system components is acceptable as a last resort. This testing will give an indication of needed repair. After repairs are made, test the charging system in order to verify that the charging system meets specifications.

Test Tools For The Charging System

Table 1
Tools Needed
Part Number Part Name Quantity
225-8266 Ammeter Tool Gp 1
Digital Multimeter Gp
Digital Multimeter Gp

225-8266 Ammeter Tool Gp

Illustration 1 g02231196
225-8266 Ammeter Tool Gp

The 225-8266 Ammeter Tool Gp is portable. This ammeter is a self-contained instrument that measures electrical currents without breaking the circuit and without disturbing the conductor insulation.

The ammeter contains a digital display that is used to monitor current directly within a range between 1 A and 1200 A. In order to view current readings of less than 1 A use the multimeter display. In order to read the multimeter display connect a 6V-6014 Cable between the digital multimeter and the ammeter. The ammeter then sends the current measurement to the multimeter display.

A lever opens the ammeter jaws over a conductor. The conductor diameter cannot be larger than 19 mm (0.75 inch).

The spring loaded jaws close around the conductor for measuring the current. A trigger switch controls the ammeter. The trigger switch can be locked into the ON position or into the OFF position.

After the trigger is turned to the OFF position, the reading appears in the digital display for 5 seconds. This meter accurately measures currents in areas with a limited access. For example, these areas include areas that are beyond the sight of the operator. For DC operation, the ammeter contains a zero control. Batteries inside the handle supply the power.

Note: Refer to the user manual for more information about using the 225-8266 Ammeter Tool Gp .

237-5130 Digital Multimeter Gp or 146-4080 Digital Multimeter Gp

Illustration 2 g02231214
237-5130 Digital Multimeter Gp or 146-4080 Digital Multimeter Gp

The 237-5130 Digital Multimeter Gp or the 146-4080 Digital Multimeter Gp is a portable, hand-held service tool with a digital display. This multimeter is built with extra protection against damage in field applications. The multimeter is equipped with 7 functions and 29 ranges. The 237-5130 Digital Multimeter Gp or the 146-4080 Digital Multimeter Gp has an instant ohms indicator. This indicator permits checking continuity for a fast inspection of the circuits. The multimeter can also be used for troubleshooting capacitors that have small values.

Note: Refer to the manual that is provided by the supplier for more information on the use of the 237-5130 Digital Multimeter Gp . Refer to Operation Manual, NEHS0678 for complete information for the use of the 146-4080 Digital Multimeter Gp .

Charging System
To check for correct output of the alternator, see the Specifications module. Refer to Special Instruction, REHS0354, “Charging System Troubleshooting”. If the part number for the alternator to be tested is not listed in the Special Instruction, refer to the appropriate Specifications manual for the information needed to test the alternator.

Before the start of on-engine testing, the charging system and the battery must be checked according to the following steps.

The battery must be at least 75 percent (1.225 Sp Gr) of the full charge. The battery must be held tightly in place. The battery holder must not put too much stress on the battery.
Cables between the battery, the starter, and the engine ground must be the correct size. Wires and cables must be free of corrosion. Wires and cables must have cable support clamps in order to prevent stress on battery connections (terminals).
Leads, junctions, switches, and panel instruments that have direct relation to the charging circuit must give correct circuit control.
Inspect the drive components for the charging unit in order to be sure that the components are free of grease and oil. Be sure that the drive components can operate the charging unit.
Check the tension of the belt for the alternator pulley. Refer to the Belt Tension Chart for the correct tension of the belt.

The charging rate of the alternator should be checked when an alternator is charging the battery too much. The charging rate of the alternator should be checked when an alternator is not charging the battery enough. Make reference to the Specifications module in order to find all testing specifications for the alternators and regulators.

No adjustment can be made in order to change the rate of charge on the alternator regulators. If the rate of charge is not correct, a replacement of the regulator is necessary.

Tightening The Alternator Pulley Nut

Illustration 3 g01247292
Tools for tightening the alternator pulley nut

(1) 8T-9293 Torque Wrench

(2) 261-0444 Adapter

(3) 2P-8267 Hex Bit Socket

(4) 8H-8517 Combination Wrench (1-1/8 inch)

(5) 8T-5314 Adapter Socket

Tighten the nut that holds the pulley with the tools shown. Refer to the Specifications manual for the torque.

The voltage regulator is a solid-state electronic switch. The regulator senses the voltage of the system and controls the field current to the alternator. The output voltage from the alternator will supply the needs of the battery. The output voltage will also supply the other components in the electrical system.

Posted in C18

Leave a Reply

Your email address will not be published. Required fields are marked *