The XQ power modules utilize a 20 A battery charger to keep the batteries at full charge. The battery charger is only required while the engine is not running. The engine has an on-board alternator that will charge the batteries as the engine runs. However, there is no circuitry that will prevent the battery charger from operating when the engine is running.
To maintain the charge for the batteries, operate the engine at regular intervals if there is not enough shore power to operate the battery charger.
The battery charger has a three-digit display. The display is used to show DC volts and DC amps. The display will show both the voltage and current readings between the battery and the charger. The display will alternate the readings that are displayed. The voltage will be displayed for 3 seconds and then the current will be displayed for 6 seconds. The display will continue to repeat the voltage and current values.
Table 1 lists the battery charger indicator status lights and definitions.
| Status Light | Problem |
| CHGR FAIL (Red) | Battery Charger has failed |
| DC HIGH (Red) | Battery DC is too High |
| DC LOW (Red) | Battery DC is too Low |
| AC FAIL (Red) | AC source input is not connected or not turned on |
| T-COMP ACTIVE (Green) | Temperature Compensation is active |
| AC/ON (Green) | AC source input is connected |
| FLOAT MODE (Green) | Charger Output is in Float Mode |
| BOOST MODE (Amber) | Charger Output is in Boost Mode |
| BATT FAULT (Red) | Check battery |
| NOTICE |
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When connecting the battery charger, connect the DC leads directly to the battery and not on the switched side of the key switch. If improperly connected, the battery charger could send a surge of current through the control system when the key switch is turned off. The surge would damage the electronic components. |
Input DI04 is used to connect the battery charger to the DIO module. If "Custom Event #4" appears on the EMCP, the battery charger fail indication is active. One of four alarms can trigger the event:
- Battery fault alarm
- Charger fail alarm
- High battery alarm
- Low battery alarm
Check the battery charger for proper operation. If the batteries are properly charged, the needle of the ammeter will register near "0" (zero).
The battery charger must not produce excessive current during start-up. Alternatively, automatically disconnect the charger for start-up. If the engine has an alternator, automatically disconnect the charger during start-up and during engine operation.
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Never disconnect any charging unit circuit or battery circuit cable from the battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result. |
Perform the following procedure to charge the battery:
- Ensure that the charger is turned OFF.
- Adjust the voltage of the charger in order to match the voltage of the battery.
- Connect the POSITIVE "+" lead of the charger to the POSITIVE "+" battery terminal. Connect the NEGATIVE "-" lead of the charger to the NEGATIVE "-" battery terminal.
- Turn ON the battery charger.
Overcharging reduces the service life of batteries. Use a battery charger that will not overcharge the battery. DO NOT charge the battery if the meter of the battery charger is in the RED zone.
Overcharging is indicated by the following symptoms:
- The battery is warm to the touch.
- A strong odor of acid is present.
- The battery emits smoke or a dense vapor (gas).
Perform one of the following procedures if the battery shows symptoms of overcharging:
- Reduce the rate of charging by a significant amount. Complete the charging at the reduced rate.
- Turn OFF the charger.
Table 2 describes the effects of overcharging on different types of batteries.
| Effects of Overcharging Batteries | |
| Type of Battery | Effect |
| Caterpillar General Service Batteries
Caterpillar Premium High Output Batteries |
All of the battery cells have a low level of electrolyte. |
| When the plates of the battery are inspected through the filler holes, the plates may appear to be warped. This condition is caused by an excessive temperature. | |
| The battery may not pass a load test. | |
| Caterpillar Maintenance Free Batteries | The battery may not accept a charging current. |
| The battery may not pass a load test. | |
Ensure that the battery charger is connected properly. Observe the meter of the charger. Record the amperage.