Sierra 1500 2WD V8-5.3L Hybrid (2004)
Battery System, Hybrid Drive: Description and Operation
ENERGY STORAGE BOX (ESB) DESCRIPTION AND OPERATION
ENERGY STORAGE BOX (ESB)
The energy storage box (ESB) subsystem provides the capability to store electrical energy as chemical energy to provide the energy required by the
Energy Management System. The ESB shall monitor the energy exchange along the 42-volt bus internal to the ESB and to provide status information
to the hybrid control module (HCM). The 3 valve-regulated lead-acid batteries provide power for the 42-volt system. The "deep cycle" batteries
employ Absorbent Glass Mat technology, specifically designed for hybrid vehicles, and are tailored to GM performance requirements-Lead-acid
batteries are less costly to replace than nickel-metal hydride batteries or other battery technologies. They have a 50 to 55 amp hour Ahr. capacity and
a projected 4-year life. The batteries are stored in a single energy storage module mounted under the rear seat. They power the electro-hydraulic power
steering (EHPS) and the starter/generator. A conventional under-hood battery powers all the other electrical items, like the lighting, the driver
information center (DIC) and the Infotainment system. The ESB physical content as follows:
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3-Panasonic HV1255V valve regulated lead acid batteries, wired in series.
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Energy storage control module (ESCM)
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Service disconnect switch
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2-120 V AC duplex outlet
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Battery module vent tubing system
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42-volt bus fuse
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12-volt ventilation fan and outlet duct
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Current sensor
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42-volt harness and connector
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12-volt connector and harness
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120 V AC connector and harness
The ESB functional content as follows:
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Store electrical energy into chemical energy
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Receive 42-volt DC energy via the 42-volt bus for charging
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Determine appropriate power mode
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Monitor and calculates energy transfer and status
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Monitor temperature of batteries
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Monitor and control fan speed.
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Monitor and control the battery cut-off (BCO) switch.
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Provide an outlet interface to HVAC ventilation duct
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Provide removal of battery gases
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Provide a side impact 42-volt auto disconnect
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Communicate faults/information via LAN messages
IMPORTANT: The Panasonic HV1255 VRLA batteries used in service will have approximately 80 percent state of charge (SOC) when shipped
from the manufacture. BEFORE battery replacement, both the battery pack and faulty battery must be fully charged at the pack level (together) to
ensure the vehicle battery pack will be equally balanced and charged. The new replacement battery will be charged to 100 percent SOC using the J
42634 Battery Module Charger before installation. Refer to Battery Charging (Non - HP2)Battery Charging (HP2). The Service Charge Procedure
MUST be performed at the pack level if:
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The vehicle is not operated for a period of time.
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The energy storage box (ESB) battery pack is less than 45 percent SOC.
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One or more batteries are diagnosed for replacement.
SERVICE CHARGE PROCEDURE
1. Install a scan tool.
2. Service Disconnect in the ON position.
3. Connect a MANUAL battery charger to the underhood battery positive remote jumper stud refer to engine ground. Turn on the battery charger and
set to 40-amp setting.
4. Turn ON the ignition.
5. Select the SGCM Service Charge Procedure from Special Functions/SGCM Output Controls and select ON.
6. Turn OFF the ignition and disconnect the scan tool.
The starter/generator control module (SGCM) will continue the charging process and control the charging rate with the scan tool disconnected and the
ignition off. The SGCM monitors the battery pack and will stop the Service Charge Procedure when 100 percent SOC is met. The battery charger will
display a low current output when the process is complete and without battery damage. Base voltage for 100 percent SOC is +/-0.2 volts from 13
volts. The procedure is completed in 4-5 hours maximum.
The Panasonic batteries are designed to have a life span of approximately 62,000 amp hours.
If all 3 batteries are replaced, the total Ahrs.must be reset with a scan tool, through BECM Output Controls.
Individual Battery Charging: Replacement of one or more batteries require a unique charging procedure that must be followed for proper vehicle
