Aircraft Batteries Flashcards
A battery is a device that converts _____contained within its active materials into ______ by means of an electrochemical reaction.
A battery is a device that converts chemical energy contained within its active materials into electrical energy by means of an electrochemical reaction.
Two metals placed in a conductive and reactive chemical solution will produce a difference in potential, called ______. If you own a boat and are constantly battling corrosion on all the metal parts, you know this chemical reaction as electrolysis.
Two metals placed in a conductive and reactive chemical solution will produce a difference in potential, called voltage. If you own a boat and are constantly battling corrosion on all the metal parts, you know this chemical reaction as electrolysis.
The cells in a battery can be connected in series to provide an increase in _____, or in parallel to provide an increase in ______.
The cells can be connected in series to provide an increase in voltage, or in parallel to provide an increase in current.
Batteries are rated by their ability to produce a certain power for a given period of time. This is called the battery’s_____ rating. A battery rated at 1 Ah has the ability to maintain a current flow of _____.
Batteries are rated by their ability to produce a certain power for a given period of time. This is called the battery’s ampere-hour (Ah) rating. A battery rated at 1 Ah has the ability to maintain a current flow of 1 ampere for 1 hour.
A battery rated at 40 Ah can provide 1 amp for_____, 40 amps for _____ hour, or any combination of amps per hour resulting in 40. If 5 amps are drawn by the load, the battery can provide current for ______ hours.
A battery rated at 40 Ah can provide 1 amp for 40 hours, 40 amps for 1 hour, or any combination of amps per hour resulting in 40. If 5 amps are drawn by the load, the battery can provide current for 8 hours.
Notice that the greater the current demand of a battery, the less time is available until discharge. That is why aircraft power distribution systems, in the event of an aircraft power failure, restrict current loads to essential systems only.
A battery with 12 cells rated at 20 Ah will technically provide 4 amps for how many hours?
5
12
20
5
Ah/A=h.
20/4=5
A battery is considered discharged when its terminal voltage equals ____ per cell times _____ in the battery.
A battery is considered discharged when its terminal voltage equals 1.0 volt per cell times the number of cells in the battery. For example, a typical 24-volt, 20-cell battery would be considered discharged when the terminal voltage falls to 20 volts.
Of course, all of these numbers are based on a perfect battery with no internal losses due to high current draw. Actual values will be lower due to the internal resistance of the battery under a load.
To determine the amount of internal resistance of a battery, we need to use ____. First, determine the internal voltage of the battery by subtracting the loaded voltage from the unloaded voltage. Next, using _____, divide the internal voltage by the loaded current. The result is the battery’s internal resistance.
To determine the amount of internal resistance of a battery, we need to use Ohm’s Law. First, determine the internal voltage of the battery by subtracting the loaded voltage from the unloaded voltage. Next, using Ohm’s Law, divide the internal voltage by the loaded current. The result is the battery’s internal resistance.
Batteries can be designed to produce higher voltages by each of the following except _______ .
increasing the number of cells connected in series
selecting higher voltage-producing metals and
electrolyte combinations
connecting the cells in parallel
connecting the cells in parallel
What is the internal resistance of a battery that has an unloaded voltage of 25.2 volts and a loaded voltage of 20 volts? Its load current is 15 amps.
- 35 ohms
- 2 ohms
35 ohms
0.35 ohms
As an aircraft maintenance technician, you will encounter many types of batteries as you service and repair aircraft. Flashlights have _____batteries; emergency locator beacons employ _____ batteries; and aircraft power is usually supplied by _______ batteries.
As an aircraft maintenance technician, you will encounter many types of batteries as you service and repair aircraft. Flashlights have alkaline batteries; emergency locator beacons employ lithium, mercury, or silver-zinc batteries; and aircraft power is usually supplied by lead-acid or nickel-cadmium batteries.
______ batteries are most common in light, general aviation aircraft because they are relatively inexpensive and are easy to maintain.
Lead-acid batteries are most common in light, general aviation aircraft because they are relatively inexpensive and are easy to maintain.
Each cell of a lead-acid battery is constructed of lead plates between a solution of ______. The positive plate consists of a lead alloy grid filled with lead dioxide. The negative plate, which stores the electrons, consists of porous lead. The sulfuric acid is mixed with water and changes in chemical composition depending on the charge of the cell.
Each cell of a lead-acid battery is constructed of lead plates between a solution of sulfuric acid. The positive plate consists of a lead alloy grid filled with lead dioxide. The negative plate, which stores the electrons, consists of porous lead. The sulfuric acid is mixed with water and changes in chemical composition depending on the charge of the cell.
A space is provided under the plates of the lead-acid battery to allow for _____. This prevents the battery from shorting due to any sediment particles touching the plates.
A space is provided under the plates of the lead-acid battery to allow for the collection of sediment. Collecting the sediment in this space prevents the battery from shorting due to any sediment particles touching the plates.
During normal battery operation, electrons flow from the ______ to the _____ plates.
During normal battery operation, electrons flow from the electron-saturated negative plates through the aircraft circuit and back to the positive plates.
A fully charged lead-acid battery will not freeze in moderately cold temperatures because _______. However, as the battery discharges, it is more susceptible to freezing as the percentage of the ______ becomes less.
A fully charged lead-acid battery will not freeze in moderately cold temperatures because its electrolyte is mostly acid. However, as the battery discharges, it is more susceptible to freezing as the percentage of the electrolyte solution becomes less acidic.
Internally in a lead-acid battery, the voltage across each set of plates is approximately ____ volts. A typical aircraft lead-acid battery has 12 cells connected in series to produce 25.2 volts at the terminal with no load. Remember, due to internal resistance, the actual loaded voltage is approximately 24 volts.
Internally in a lead-acid battery, the voltage across each set of plates is approximately 2.1 volts. A typical aircraft lead-acid battery has 12 cells connected in series to produce 25.2 volts at the terminal with no load. Remember, due to internal resistance, the actual loaded voltage is approximately 24 volts.
The charge of a lead-acid battery can be determined by measuring the _______ of the electrolyte in each cell.
The charge of a lead-acid battery can be determined by measuring the specific gravity of the electrolyte in each cell. The electrolyte in a fully charged cell will have a specific gravity of approximately 1.285 or greater, while the electrolyte in a fully discharged cell will have a specific gravity of 1.150 or less.
Name the battery
The gases generated by batteries during the charging cycle are explosive. A proper mechanical ventilation system must be installed in the battery shop. The ventilation system should provide at least _______ complete air changes per hour to prevent the buildup of explosive gas.
The gases generated by batteries during the charging cycle are explosive. A proper mechanical ventilation system must be installed in the battery shop. The ventilation system should provide at least 3 to 4 complete air changes per hour to prevent the buildup of explosive gas.
Temperature affects the charging capacity of batteries. The most efficient temperature for charging batteries is between _______. Charging should never be attempted below 20 °F (-7 °C) or above 120 °F (50 °C).
Temperature affects the charging capacity of batteries. The most efficient temperature for charging batteries is between 60 °F (15 °C) and 90 °F (32 °C). Charging should never be attempted below 20 °F (-7 °C) or above 120 °F (50 °C).
Neutralizers are chemicals that have a pH level which is opposite of the battery’s electrolyte. Each shop should have neutralizer on hand in the event of a spill or splash. The neutralizer for a lead-acid battery shop is _________
Neutralizers are chemicals that have a pH level which is opposite of the battery’s electrolyte. Each shop should have neutralizer on hand in the event of a spill or splash. The neutralizer for a lead-acid battery shop is sodium bicarbonate (baking soda) and water.
The neutralizer for the Ni-Cd battery shop is ________
The neutralizer for the Ni-Cd battery shop is a 3% solution of acetic acid, vinegar, or lemon juice.
Every battery shop must have a fire extinguisher mounted on the wall and free of obstructions. Typically,_____ extinguishers are used in battery shops. Never use a _____ fire extinguisher to cool an overheated battery. When discharged, ______ extinguishers build up static electricity which could result in a spark.
Every battery shop must have a fire extinguisher mounted on the wall and free of obstructions. Typically, Halon fire extinguishers are used in battery shops. Never use a CO2 fire extinguisher to cool an overheated battery. When discharged, CO2 extinguishers build up static electricity which could result in a spark.
