This document discusses aircraft batteries. It covers the sources of electricity on aircraft, battery usage during transient conditions or to power heavy loads when other power sources are unavailable. It describes the principle of batteries, which involves a chemical reaction that produces electrons. It details the construction of batteries as well as the types of cells, including lead-acid and nickel-cadmium batteries. It also addresses capacity rating, battery location and venting, charging and discharging processes, and methods to indicate the state of charge.

1. Batteries
(Accumulators)
EgyptAir
Technical Training Center
By Engineer: Amr Eissa

2. Batteries EgyptAir Training Center 2
Battery Outlines
 Sources of Electricity on Aircraft.
 Battery Usage.
 Battery Principle of Operation.
 Battery Construction.
 Types of Cells.
 Lead Acid Battery Construction and
Chemical Action.

3. Batteries EgyptAir Training Center 3
 Ni-Cd Battery Construction and Chemical
Action.
 Capacity Rating.
 Battery Location and Venting.
 Battery Charging and Discharging.
 Method to Indicate The State of Charge.
 Typical Battery System Circuit.
Battery Outlines Cont.

4. Batteries EgyptAir Training Center 4
Sources of Electricity

5. Batteries EgyptAir Training Center 5
Batteries usage at
1. Transient conditions.
(At starting large D.C motor…).
2. Supplying power for short term to heavy loads.
(when generator or ground power is not available, at
Engine, APU starting).
3. Emergency conditions.
(to operate flight instruments…For 30 min as the
capacity of the batteries allow).

6. Batteries EgyptAir Training Center 6
Batteries Principle of Operation
Principle based on:
Change Of Chemical Energy To Electrical Energy.
The exchange of electrons between the Electrodes
through an Electrolyte due to chemical reactions.

7. Batteries EgyptAir Training Center 7
Battery Construction
 An aircraft battery consists of a number of individual
cells interconnected together.
 It contain separators between plates.
 Each cell consists of an odd number of -Ve plates and
even number of +Ve plates.
 the plate assemblies are supported
in acid-proof container.
R

8. Batteries EgyptAir Training Center 8
Battery Construction Cont.

9. Batteries EgyptAir Training Center 9
 Terminal posts are connected by cell straps and
brought out to a main receptacle for connection into
the aircraft’s main wiring.
- +
-
+ -
+ -
+
- +
- +
Cell Strap
Cell
Main Receptacle
Battery Construction Cont.

10. Batteries EgyptAir Training Center 10
Types of Cells
Primary Cell Secondary Cell

11. Batteries EgyptAir Training Center 11
Types of Cells
Primary Cell Secondary Cell
Output
Power
Charging
Active
Material
Life Time

12. Batteries EgyptAir Training Center 12
Types of Batteries
 Lead Acid Battery.
 Nickel Cadmium Battery.
Battery type is derived from the plate material
(electrodes) and liquid (electrolyte) that is used
during construction.

13. Batteries EgyptAir Training Center 13
Lead Acid Battery
Construction:
 @ Charging it Consists of
 @ Discharging it Consists of
 Relative Density

14. Batteries EgyptAir Training Center 14
Nickel Cadmium Battery
Construction:
 @ Charging it Consists of
 @ Discharging it Consists of
 Relative Density

15. Batteries EgyptAir Training Center 15
Capacity Rating
 The maximum current, in amperes, which the battery
will deliver for a known time period, in hours, until
the output voltage has fallen to minimum value,
measured in
AMPERE-HOURS (AH).
 What’s the factors The Battery capacity Rating depend
on ???

16. Batteries EgyptAir Training Center 16
Capacity Rating Cont.

17. Batteries EgyptAir Training Center 17
Nickel Cadmium Lead Acid
Lead Acid Vs. Ni-Cad Batteries

18. Batteries EgyptAir Training Center 18
Battery Location
Batteries located within the aircraft's main
electrical equipment bay where “Adequate heat
dissipation, ventilation and protection is
provided”.

19. Batteries EgyptAir Training Center 19
Battery Location & Venting

20. Batteries EgyptAir Training Center 20
Battery Charging & Discharging
 Battery will be CHARGING when
 Battery will be DISCHARGING when
Discharge Rate
It is the time taken to discharge until a permissible
minimum voltage.

21. Batteries EgyptAir Training Center 21
Battery Charging
The two methods of battery charging are:-
 Constant Voltage.
 Constant Current (used).

22. Batteries EgyptAir Training Center 22
Constant Voltage Charging Method

23. Batteries EgyptAir Training Center 23
Constant Current Charging Method

24. Batteries EgyptAir Training Center 24
Thermal Runaway
It is the condition which causes violent gassing,
boiling of electrolyte and finally melting of plates.
Increase
Charging
Current
Increase
Battery
Temperature

25. Batteries EgyptAir Training Center 25
Methods To Indicate State Of Charge
For Lead Acid battery:
 The Terminal Voltage reaches max. value and remain
steady (used to determine full charged state only).
 The Relative Density of the electrolyte ceases of rise
and remain constant, it is measured by hydrometer
(can’t be used neither in batteries has Absorbed
electrolyte nor in Ni-Cd battery).
For Ni-Cd battery:
 Formation of White Crystals of potassium Carbonate
”Reaction Between electrolyte vapor and CO2 “
(used to indicate an overcharged condition)

26. Batteries EgyptAir Training Center 26
Battery Charger System