W DOC AIRBUS | AMM A320F

DC GENERATION - BATTERIES - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL
1. General
The DC generation is provided by two batteries.
Each of them has a nominal capacity of 23 Ah.
The DC generation is provided by two batteries.
Each of them has a nominal capacity of 28 Ah.
They are mainly used to:
  • start the APU in flight and on ground,
  • supply AC/DC essential network in emergency configuration during RAT deployment and when the emergency generator is not available (CSM/G switched off after landing).
Each battery is associated with a Battery Charge Limiter (BCL) and a battery shunt.
It should be noted that, in normal configuration, the batteries are most of the time uncoupled from the network during the flight.
** ON A/C NOT FOR ALL
2. Component Location
F DC Generation - Batteries - Component Location
F DC Generation - Batteries - Component Location
F DC Generation - Batteries - Component Location
F DC Generation - Batteries - Component Location
F DC Generation - Battery Shunt - Component Location
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FIN I FUNCTIONAL DESIGNATION I PANELIZONEIACCESS I ATA
I I I I DOOR I REF.
-------------------------------------------------------------------------------
4PB11 FUSE BAT-1 120VU 212 24-38-00
4PB21 FUSE BAT-2 120VU 212 24-38-00

FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C NOT FOR ALL
1PB1 BCL-1 124 24-38-34
1PB2 BCL-2 124 24-38-34
** ON A/C NOT FOR ALL
1PB1 BCL-1 126 24-38-34
1PB2 BCL-2 126 24-38-34
** ON A/C ALL
2PB1 BAT-1 126 24-38-51
2PB2 BAT-2 126 24-38-51
3PB1 SHUNT-BAT 1 126 24-38-54
3PB2 SHUNT-BAT 2 126 24-38-54
** ON A/C NOT FOR ALL
4PB1 HOLDER-BAT 1 FUSE 120VU 212 24-38-00
4PB2 HOLDER-BAT 2 FUSE 120VU 212 24-38-00
** ON A/C ALL
6PB1 CNTOR-LINE, BAT 1 105VU 126 24-38-55
6PB2 CNTOR-LINE, BAT 2 120VU 212 24-38-55
7PB1 P/BSW-ELEC/BAT 1 35VU 210 24-38-00
7PB2 P/BSW-ELEC/BAT 2 35VU 210 24-38-00
** ON A/C NOT FOR ALL
3. Component Description
A. Batteries FIN: 2-PB-1 FIN: 2-PB-2
Each battery of the nickel-cadmium type is composed of twenty elements housed in a stainless steel case.
Characteristics:
  • nominal voltage: 24 V,
  • nominal capacity: 23 Ah,
  • high instantaneous power,
  • electrolyte reserve: 60 cubic centimeters,
  • two ventilation ducts.
Each battery of the nickel-cadmium type is composed of twenty elements housed in a stainless steel case.
Characteristics:
  • nominal voltage: 24 V,
  • nominal capacity: 28 Ah,
  • high instantaneous power,
  • electrolyte reserve: 55 cubic centimeters,
  • two ventilation ducts.
B. Battery Charge Limiter (BCL)
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! FUNCTION ! THRESHOLD ! TIME DELAY ! ACTION ! No.!
!-----------------------------------------------------------------------------!
! Control of ! - Battery charge ! ! !BAT.CNTOR! !
! battery ! . Charging !VBAT < 26,5 V! 225 ms ! CLOSING ! 7 !
! contactor ! cycle !& V3PP > 27 V! ! ! !
! ! ! ! ! ! !
! ! . end of ! ICH < 4 A ! 10 s ! OPENING ! 6 !
! ! charging ! ! ! ! !
! ! cycle on ! ! ! ! !
! ! ground ! ! ! ! !
! ! ! ! ! ! !
! ! . end of ! ICH < 4 A ! 30 mn ! OPENING ! !
! ! charging ! ! ! ! !
! ! cycle if ! ! ! ! !
! ! aircraft ! ! ! ! !
! ! speed is ! ! ! ! !
! ! greater than ! ! ! ! !
! ! 100 Kts ! ! ! ! !
! ! or after an ! ! ! ! !
! ! APU start ! ! ! ! !
! ! ! ! ! ! !
! ! - Thermal runaway! ! ! ! !
! ! (1) ! ! ! ! !
! ! . -------------! ICH > 10 A ! 3 X 60 s ! OPENING ! 5 !
! ! !& >0,375 A/mn! ! ! !
! ! ! ! ! ! !
! ! ! ! ! ! !
! ! .--------------! ICH > 150 A ! 90 s ! OPENING ! 4 !
! ! ! ! ! ! !
! ! - Starting of APU! ! ! CLOSING ! 8 !
! ! ! ! ! ! !
! ! - Supply on ! ! 75 ms ! CLOSING ! 3 !
! ! ground ! ! ! ! !
! ! ! ! ! ! !
! ! - Transient fault! V3PP < 5 V ! ! CLOSING ! 2 !
! ! conditions ! ! ! ! !
! ! ! ! ! ! !
! ! - Integrity of ! IDECH >100 A! 300 ms ! OPENING ! 1 !
! ! hot bus ! ! ! ! !
! ! ! ! ! ! !
! ! - Electrical ! ! ! OPENING ! 10 !
! ! emer condition ! ! ! ! !
!-----------------------------------------------------------------------------!
! Control of BCL! - Complete ! VBAT < 23 V ! 15 s ! OPENING BCL !
! supply ! discharge ! ! ! SUPPLY !
! ! protection ! ! ! !

-------------------------------------------------------------------------------
! FUNCTION ! THRESHOLD ! TIME DELAY ! ACTION ! No.!
!-----------------------------------------------------------------------------!
! Control of ! - Battery charge ! ! !BAT.CNTOR! !
! battery ! . Charging !VBAT < 26,5 V! 225 ms ! CLOSING ! 7 !
! contactor ! cycle !& V3PP > 27 V! ! ! !
! ! ! ! ! ! !
! ! . end of ! ICH < 4 A ! 10 mins ! OPENING ! 6 !
! ! charging ! ! ! ! !
! ! cycle on ! ! ! ! !
! ! ground ! ! ! ! !
! ! ! ! ! ! !
! ! . end of ! ICH < 4 A ! 30 mins ! OPENING ! !
! ! charging ! ! ! ! !
! ! cycle if ! ! ! ! !
! ! aircraft ! ! ! ! !
! ! speed is ! ! ! ! !
! ! greater than ! ! ! ! !
! ! 100 Kts ! ! ! ! !
! ! or after an ! ! ! ! !
! ! APU start ! ! ! ! !
! ! ! ! ! ! !
! ! - Thermal runaway! ! ! ! !
! ! (1) ! ! ! ! !
! ! . -------------! ICH > 10 A ! 3 X 60 s ! OPENING ! 5 !
! ! !& >0,375 A/min ! ! !
! ! ! ! ! ! !
! ! ! ! ! ! !
! ! .--------------! ICH > 150 A ! 90 s ! OPENING ! 4 !
! ! ! ! ! ! !
! ! - Starting of APU! ! ! CLOSING ! 8 !
! ! ! ! ! ! !
! ! - Supply on ! ! 75 ms ! CLOSING ! 3 !
! ! ground ! ! ! ! !
! ! ! ! ! ! !
! ! - Transient fault! V3PP < 5 V ! ! CLOSING ! 2 !
! ! conditions ! ! ! ! !
! ! ! ! ! ! !
! ! - Integrity of ! IDECH >100 A! 300 ms ! OPENING ! 1 !
! ! hot bus ! ! ! ! !
! ! ! ! ! ! !
! ! - Electrical ! ! ! OPENING ! 10 !
! ! emer condition ! ! ! ! !
!-----------------------------------------------------------------------------!
! Control of BCL! - Complete ! VBAT < 23 V ! 15 s ! OPENING BCL !
! supply ! discharge ! ! ! SUPPLY !
! ! protection ! ! ! !

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! FUNCTION ! THRESHOLD ! TIME DELAY ! ACTION ! No.!
!-----------------------------------------------------------------------------!
! "RAT-CSM/G ! ! ! ! WARNING !
! FAULT" ! ! ! ! !
! warning ! - ! - ! 1 s ! LIGHT !
! control ! ! ! ! !
!-----------------------------------------------------------------------------!
! Inhibition of ! ! When ELEC ! 45 s ! APU START !
! APU start ! ! EMER ! ! CNTOR !
! sequence ! !configuration! ! INHIBITED !
! ! !initiated and! ! !
! ! !CSM/G not ! ! !
! ! !available ! ! !
!-----------------------------------------------------------------------------!
! "BAT FAULT" ! - Thermal runaway! ! ! WARNING !
! warning ! (see 1) ! ! ! !
! control ! ! ! ! LIGHT !

C. Battery Shunt
A 400 A/75mV shunt is installed on a base. It is used to read the charging and the discharging currents of a 24 V, 23 Ah battery.
Characteristics:
  • Rating: the shunt supplies a voltage of 75 mV when a 400 A current goes through it.
  • Accuracy: 1% at 20 deg.C in the 0 - 400A range.
  • Overload capacity: 600 A during 30 seconds, 1000 A during 5 seconds.
  • Max. weight: 300 g.
A 400 A/75mV shunt is installed on a base. It is used to read the charging and the discharging currents of a 24 V, 28 Ah battery.
Characteristics:
  • Rating: the shunt supplies a voltage of 75 mV when a 400 A current goes through it.
  • Accuracy: 1% at 20 deg.C in the 0 - 400A range.
  • Overload capacity: 600 A during 30 seconds, 1000 A during 5 seconds.
  • Max. weight: 300 g.
** ON A/C NOT FOR ALL
4. Operation/Control and Indicating
A. Control and Indicating Circuits
F Battery Charge Limiter (BCL1) - Shematic Simplified Cockpit Compartment Controls and Indicating
The operation of each battery charge limiter is controlled from the ELEC panel 35VU in the cockpit by means of BAT1(2) pushbutton switches. These pushbutton switches have two stable positions:
(1) The pushbutton switch is released
The battery charge limiter is not operating and the battery is uncoupled from the network.
The status of this control is indicated by illumination of the white OFF legend on the pushbutton switch. The same indication is displayed on the ELEC page of the lower ECAM Display Unit and generates a warning if one or both engines are running.
(2) The pushbutton switch is pressed
The battery charge limiter is operating and controls the coupling and uncoupling of the battery.
No light comes on on the pushbutton switch in normal operation. However white BAT1 and BAT2 and green indication of voltage and current are displayed on the ELEC page of the lower ECAM DU, as well as the green symbol when battery is charging and the amber symbol when battery is discharging.
FAULT amber legend comes on on the pushbutton switch if a thermal runaway or internal short-circuit is detected. Simultaneously, the ELEC page is displayed on the lower ECAM DU with corresponding warnings (MASTER CAUT light + single chime + amber message on the upper ECAM display unit).
A BAT OVHT fault causes automatic lock out of the battery line contactor.
NOTE: An OFF/ON (Released/Pressed) action on the pushbutton switch allows to reset the BCL.
B. General Operating Principle of the Battery Charge Limiter
The battery charge limiter has a main function which is to control the battery contactor and three auxiliary functions which are:
  • RAT & EMER GEN FAULT warning control,
  • in emergency configuration, inhibition of APU start sequence during RAT deployment,
  • BAT FAULT warning control.
Furthermore, the BCL delivers battery-related parameters and warnings to the ECAM display units, through busses.
C. Battery Charge Limiter Functions
The functions of battery charge limiter are as follows:
(1) Control of the battery contactor:
  • to ensure battery charge,
  • to start or assist starting of the APU,
  • to protect the battery against thermal runaway or short circuit,
  • to control equipment DC supply on ground, when no normal power is available,
  • to prevent complete discharge of the battery, when the aircraft is parked,
  • to supply equipment with DC during transient fault configurations,
  • to ensure integrity of the HOT bus.
(a) Battery charge
When battery voltage is lower than 26.5 V, beginning of the charging cycle.
When battery charge current is lower than 4 A, end of the charging cycle.
NOTE: In flight or following APU start, when the battery charge current is lower than 4 A, a 30 mn time delay in the BCL controls the end of the charging cycle.
(b) Thermal runaway and internal short circuit
Battery isolation occurs in case of:
  • charge current increasing with a slope greater than 0.375 A/mn.
  • charge current greater than a threshold (150 A) during 1 minute and 30 seconds.
(c) Starting of the APU
When the APU start sequence is initiated, the two batteries are connected to 28 VDC BAT BUS (3PP) to supply the APU starter motor.
(d) Supply on ground
When IDG's, APU generator or external power are not available on ground, the batteries supply:
  • the 28 VDC BAT BUS (3PP) through the contactors 6PB1 and 6PB2,
  • the 28 VDC ESS BUS (4PP) through the contactor 2XB,
  • the 115 VAC STAT INV BUS (901XP) through the static inverter 3XB.
(the BAT1(2) pushbutton switches are pushed).
(e) Protection against complete discharge
On ground, the batteries are automatically disconnected from the DC network when battery voltage is lower than 23 V during 15 seconds.
NOTE: But the disconnected battery always supplies its related HOT bus.
(f) Transient fault conditions
Battery contactors are closed during 7 seconds when DC network is lost.
(g) Integrity of the HOT bus
Battery isolation in case of failure on DC network through monitoring of the battery discharge current (either I discharge > 400 A for 5 ms or I discharge > 100 A for 300 ms).
(h) Electrical emergency event
Battery isolation in case of AC normal busbars failure (loss of AC main generation) except when APU start sequence is initiated.
(2) RAT & EMER GEN control
In case of AC normal busbars failure (loss of AC main generation) the red FAULT legend of the RAT & EMER GEN pushbutton switch on the ELEC EMER PWR section of the overhead panel 21VU comes on until the emergency generator is available (operational). The FAULT legend is inhibited when the landing gear is compressed.
(3) Inhibition of the APU start sequence
In flight, when the electrical emergency configuration is initiated, the APU start sequence is inhibited during 45 seconds.
NOTE: If the CSM/G comes on line before 45 seconds, the APU start sequence is available as soon as the CSM/G is coupled to the network.
(4) BAT - Fault warning control
When a thermal runaway occurs the FAULT legend of the BAT1(2) pushbutton switch comes on on the overhead ELEC panel 35VU.
The battery contactors are opened but no action is required from the crew.
(5) The control of the battery contactor is used to:
  • Charge the battery
  • Start or help the start of the APU
  • Prevent the battery against thermal runaway or short circuits
  • Control the equipment DC supply on ground when no external power is available
  • Prevent full discharge of the battery when the aircraft is parked
  • Supply equipment with DC during temporary fault configurations
  • Make sure that there is integrity of the HOT bus.
(a) Battery charge
When the battery voltage is less than 26.5 V, the charging cycle starts.
When the battery charge current is less than 4 A, it is the end of the charging cycle.
NOTE: In flight or during the APU start, when the battery charge current is less than 4 A, a 30-minute time delay in the BCL controls the end of the charging cycle.
NOTE: On ground, when the battery charge current is less than 4 A, a 10-minute time delay in the BCL controls the end of the charging cycle.
(b) Thermal runaway and internal short circuit
The operator must isolate the battery when:
  • The battery charge current increases to more than 0.375 A/minute
  • The battery charge current is more than the 150 A threshold for one minute and 30 seconds.
(c) Start of the APU
When the APU start sequence starts, the two batteries are connected to the 28 VDC BAT BUS (3PP) to supply power to the APU starter motor.
(d) Supply on ground
When the Integrated Drive Generators (IDG), the APU generator or the external power are not available on ground, the batteries supply power to:
  • The 28 VDC BAT BUS (3PP) through battery contactors 6PB1 and 6PB2
  • The 28 VDC ESS BUS (4PP) through battery contactor 2XB
  • The 115 VAC STAT INV BUS (901XP) through static inverter 3XB.
NOTE: The BAT1(2) pushbutton switch is pushed.
(e) Protection against full discharge
On ground, the batteries are automatically disconnected from the DC network when the battery voltage is less than 23 V for 15 seconds.
NOTE: The disconnected battery always supplies power to its related HOT bus.
(f) Temporary fault conditions
The battery contactors close for seven seconds when the DC network is lost.
(g) Integrity of the HOT bus
The operator must isolate the battery when there is a failure on the DC network with the monitoring of the battery discharge current (I discharge > 400 A for five ms or I discharge > 100 A for 300 ms).
(h) Electrical emergency
The operator must isolate the battery when there is a failure of the AC busbars (loss of AC main-power generation) but not when the APU start sequence starts.
(6) RAT & EMER GEN control
If there is a failure of the AC busbars (loss of AC main-power generation), the red FAULT legend of the RAT & EMER GEN pushbutton switch (on the ELEC EMER PWR section of overhead panel 21VU) comes on until the emergency generator is available (serviceable).
The FAULT legend is inhibited when the landing gear is activated.
(7) Inhibition of the APU start sequence
In flight, when the electrical emergency configuration starts, the APU start sequence is inhibited for 45 seconds.
NOTE: If the Constant Speed Motor/Generator (CSM/G) operates before 45 seconds, the APU start sequence is available immediately after the CSM/G is connected to the network.
(8) BAT - fault warning control
When a thermal runaway occurs, the FAULT legend of the BAT1(2) pushbutton switch comes on, on overhead ELEC panel 35VU.
The battery contactors are open but no step is necessary from the crew.
** ON A/C NOT FOR ALL
5. BITE Test
Built-In Test Equipment (BITE) allows two types of test:
  • tests at each power up on ground,
  • tests on ground from the Centralized Fault Display System (CFDS).
Furthermore, the BCL system is monitored when the BCL is in operation.
A. Power up Test
On the ground, when the equipment is switched on, the following tests are performed:
  • EPROM test (checksum),
  • RAM test,
  • timer test,
  • discret inputs test,
  • acquisition current test,
  • test of the output stage of the battery contactor control,
  • test of the output stage of the BAT FAULT warning control,
  • test of the output stage of the RAT & CSM/G warning control,
  • test of the output stage of the APU start inhibition control,
  • test of specific external wiring of the BCL,
  • watchdog test.
B. Test from the CFDS
The same tests as those applicable to power up are performed, plus a test for correct operation of the FAULT legend of BAT1(2) pushbutton switches and of RAT & EMER GEN annunciator which lasts 6 seconds.
C. Monitoring of the BCL System
When the BCL is supplied, the peripheral circuits are monitored through validation of the inputs (for example the position of the auxiliary contact of the battery contactor shall be coherent with the order).
D. Communication with the MCDU and/or ECAM
When a class 1 failure occurs, a BITE message is transmitted to the MCDU via an ARINC 429 serial data link and a failure indication is transmitted to the ECAM.
In case of BAT FAULT warning, the crew is informed by:
  • a local amber warning on the overhead panel,
  • the single chime,
  • an amber caution on the main instrument panel.
The warning page is displayed on the upper ECAM display unit and, at the same time, the ELEC page is displayed on the lower ECAM display unit:
F BAT 1 FAULT - Lower and Upper ECAM Display Unit
F BAT 2 FAULT - Lower and Upper ECAM Display Unit
NOTE: For some more information, see ATA (Ref. AMM D/O 31-51-00-00).
In case of BCL FAULT warning, the crew is informed by the BCL FAULT message displayed on the upper ECAM display unit whereas the ELEC page is displayed on the lower ECAM display unit.
Class 3 failures can be read using the CFDS. Maintenance personnel must localize the failures by means of CFDS readouts
F Maintenance Test Procedure for BCL
NOTE: If a BAT pushbutton switch is released (OFF position), the BAT OFF warning is displayed on the upper ECAM display unit whereas the ELEC page is displayed on the lower ECAM display unit.
The BITE messages generated by the BCL's are:
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! ATA REF. ! MESSAGE ! CLASS ! COMMENT !
!----------!----------------------!-------!-----------------------------------!
! 24-38-51 ! BATTERY 1 (or 2) ! I ! Battery thermal runaway or !
! ! ! ! internal short circuit !
!----------!----------------------!-------!-----------------------------------!
! 24-28-51 ! STATIC INVERTER 3XB ! I ! Failure of static inverter !
!----------!----------------------!-------!-----------------------------------!
! 24-38-55 ! CHECK CONTACTOR ! I ! Failure of battery contactor !
! ! 6PB1 (or 6PB2) ! ! control of status circuit !
! ! BCL1 (or BCL2) ! ! !
! ! CIRCUIT ! ! !
!----------!----------------------!-------!-----------------------------------!
! 24-38-00 ! PUSHBUTTON 7PB1 ! I ! Failure of control P/BSW circuit !
! ! (or 7PB2) / BCL1 ! ! !
! ! (or BCL2) CIRCUIT ! ! !
!--------- !----------------------!-------!-----------------------------------!
! 24-38-00 ! SHUNT 3PB1 (or 3PB2) ! I ! Failure of current acquisition !
! ! /BCL1 (or BCL2) ! ! circuit !
! ! CIRCUIT ! ! !
!--------- !----------------------!-------!-----------------------------------!
! 24-38-00 ! FUSE 4PB1 (or 4PB2) ! I ! Fuse blown !
!----------!----------------------!-------!-----------------------------------!
! 24-38-34 ! BCL1 (or BCL2) ! I ! Failure of: !
! ! ! ! -analogic/numeric converter !
! ! ! ! -battery contactor control !
!----------!----------------------!-------!-----------------------------------!
! 24-38-00 ! CHECK DC BAT BUS ! I ! Failure of BCL BAT BUS supply !
! ! 3PP/BCL1 (or BCL2) ! ! !
!----------!----------------------!-------!-----------------------------------!
! 24-38-34 ! BCL1 (or BCL2) ! III ! Failure of: !
! ! ! ! -WATCH DOG !
! ! ! ! -BAT FAULT control !
! ! ! ! -APU START VALID control !
! ! ! ! -RAT/EMER GEN/FAULT control !
! ! ! ! (internal to BCL) !
!----------!----------------------!-------!-----------------------------------!
! 33-14-00 ! BOARD 5LP/BCL1 ! III ! Failure of BAT FAULT indication !
! ! (or BCL2) CIRCUIT ! ! circuit !
!----------!----------------------!-------!-----------------------------------!
! 24-24-00 ! RELAY 31XE/BCL1 ! III ! Failure of RAT/EMER GEN/FAULT !
! ! (or BCL2) CIRCUIT ! ! indication circuit !
!----------!----------------------!------ !-----------------------------------!
! 32-62-00 ! CHECK LGCIU1/BCL1 ! III ! Failure of nose L/G locked up !
! ! (or BCL2) CIRCUIT ! ! information !
!----------!----------------------!-------!-----------------------------------!
! 24-38-00 ! BCL1 (or BCL2) ! III ! Ground/flight ADIRU or LGCIU !
! ! LGCIU/ADIRU1 ! ! information disagree !
! ! SIGNAL DISAGREE ! ! !
!----------!----------------------!-------!-----------------------------------!
! 24-34-55 ! CHECK CONTACTOR ! III ! Failure of ESS TR contactor !
! ! 3PE/BCL1 (or BCL2) ! ! status circuit !
! ! CIRCUIT ! ! !
!----------!----------------------!-------!-----------------------------------!
! 24-38-00 ! CHECK HOT BUS 701PP ! III ! Failure of voltage from HOT bus !
! ! (or 702PP)/ BCL1 ! ! !
! ! (or BCL2) CIRCUIT ! ! !
!----------!----------------------!-------!-----------------------------------!
! 24-25-00 ! RELAYS 15XC or 16XC/ ! III ! Failure of emergency !
! ! BCL1 (or BCL2) ! ! configuration information !
! ! CIRCUIT ! ! !
!----------!----------------------!-------!-----------------------------------!
! 24-38-00 ! CHECK HOT BUS POWER ! III ! Abnormal consumption on HOT bus !
! ! CONSUMPTION ! ! !
!-----------------------------------------------------------------------------!

[Rev.10 from 2021] 2026.03.31 23:23:46 UTC
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