Dual Battery System - TDV8 4.4L Diesel Engine And Cold Climate TDV6 3.0L Diesel Engine Vehicles
The dual battery system on vehicles with an auxiliary battery, allows both batteries to be connected in parallel. The dual battery system provides increased amperage to the starter motor for efficient starting in cold climates. The auxiliary battery assists the primary battery in operating the starter motor to crank the engine at a sufficient speed for efficient starting.
In addition, the auxiliary battery supplies the sensitive loads when the auto stop/start is active.
The PSDB connects or isolates the batteries on receipt of Local Interconnect Network (LIN) bus information from the Body Control Module/Gateway Module (BCM/GWM) assembly.
Dual Battery System - Primary and Auxiliary batteries - Normal state (Engine Running)
A = PRIMARY BATTERY/GENERATOR SUPPLY: B = AUXILIARY BATTERY CHARGING: C = PRIMARY BATTERY CHARGING.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Starter motor/Tandem Solenoid Starter (TSS) motor |
| 2 | Generator |
| 3 | Primary battery |
| 4 | Power and engine management system loads |
| 5 | Power Supply Distribution Box (PSDB) |
| 6 | Battery 1 connection on Power Supply Distribution Box (PSDB) - Connected |
| 7 | Battery 2 connection on Power Supply Distribution Box (PSDB) - Disconnected |
| 8 | Battery 2 connection on Power Supply Distribution Box (PSDB) - Connected |
| 9 | Auxiliary battery |
| 10 | Sensitive loads |
When the engine is running, all electrical systems are powered from the primary battery and the generator. The BCM/GWM assembly and the Power Supply Distribution Box (PSDB) communicate via the LIN bus, and the PSDB isolates the auxiliary battery from the system.
The BCM/GWM assembly monitors the state of charge of both the primary and auxiliary batteries. The BCM/GWM assembly provides that sufficient voltage is available for the next auto stop/start engine start. The BCM/GWM assembly can apply charging to the auxiliary battery via the PSDB, if it is required. If the charging of auxiliary battery is necessary, the PSDB connects the auxiliary battery, and the generator starts to charge it.
Dual Battery System - Primary and Auxiliary Batteries in Parallel for Starting
A = PRIMARY BATTERY SUPPLY: B = AUXILIARY BATTERY SUPPLY.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Starter motor/Tandem Solenoid Starter (TSS) motor |
| 2 | Generator |
| 3 | Primary battery |
| 4 | Power and engine management system loads |
| 5 | Power Supply Distribution Box (PSDB) |
| 6 | Battery 1 connection on Power Supply Distribution Box (PSDB) - Connected |
| 7 | Battery 2 connection on Power Supply Distribution Box (PSDB) - Connected |
| 8 | Auxiliary battery |
| 9 | Sensitive loads |
When the ambient temperature is below a predetermined level and the BCM/GWM assembly receives a start signal the following occurs:
- The BCM/GWM assembly communicates with the PSDB via the LIN bus to keep the primary battery connected, and also connect the auxiliary battery. The power for the starter motor is supplied from both batteries.
Dual Battery system - ECO Engine Stop/Start State with Auxiliary Battery
A = PRIMARY BATTERY SUPPLY: B = AUXILIARY BATTERY SUPPLY.
| ITEM | DESCRIPTION |
|---|---|
| 1 | Tandem Solenoid Starter (TSS) motor |
| 2 | Generator |
| 3 | Primary battery |
| 4 | Power and engine management system loads |
| 5 | Power Supply Distribution Box (PSDB) |
| 6 | Battery 1 connection on Power Supply Distribution Box (PSDB) - Disconnected |
| 7 | Battery 2 connection on Power Supply Distribution Box (PSDB) - Connected |
| 8 | Auxiliary battery |
| 9 | Sensitive loads |
When the auto stop/start is required, the BCM/GWM assembly sends a signal to the PSDB via the LIN bus. The PSDB isolates the primary battery from sensitive loads. The primary battery supplies the starter motor and power loads only, to provide the quick engine start. In same time the PSDB connects the auxiliary battery to supply the sensitive loads, while the auto stop/start in progress.