Batteries
A new, fully charged, battery will have
70% water, 30% acid (by volume), and a specific gravity of 1.300
What is a storage battery?
A battery with multiple secondary cells
When is a mercury battery useful?
When size and weight outweigh the costs
Is it possible to recharge a lead-acid battery many times before it deteriorates?
Yes
Carbon-zinc battery negative pole is made of....
Zinc
What tends to dissolve away as a carbon-zinc battery is dissipated?
Zinc electrode
What produces more current, an alkaline cell or a carbon-zinc battery?
Alkaline cell, although both produce the same voltage
What are lead acid batteries used in aircraft similar to?
Automobile batteries
Why. Are common batteries sealed in a steel jacket?
Because as a battery expands energy, it tends to leak
Carbon-zinc battery positive pole is made of....
Carbon
The common flashlight has a.....
Carbon rod and an electrolyte made of ammonium chloride, manganese dioxide, and granulated carbon and in a zinc canister
A battery converts.....
Chemical energy into electrical energy
When a lead-acid battery discharges, what kind of energy does it convert?
Chemical into electrical
What does an alkaline cell use as an electrolyte?
Potassium hydroxide
The common flashlight uses a......
Primary cell
During battery discharge, the acid content is
decreasing and the water content is increasing
The state of charge is indicated by the
density of the electrolyte measured with a hydrometer
how should vent caps be left during charging?
loosened but left in place
The endplate in each cell is a
negative plate
Between a nickel-cadmium battery and a lead-acid battery, what has higher initial costs?
nickel-cadmium
What type of brush should be used when cleaning a battery?
non-conductive type brush
What is the electrolyte in a Ni-Cad battery?
30% potassium hydroxide and distilled water
How many amperes does a 35 amp hour battery produce for one hour?
35
What is the standard discharge rate for an aircraft battery?
5 hours
How many amperes does a 25 amp hour battery produce for a 1/2 hour?
50
A battery in a state of charge less than ___ needs immediate recharging
50%
A 12 volt battery has how many cells?
6
How many volts per cell does a freshly charged battery have?
2.2
Name two common high discharge rates for an aircraft battery
20 minute and 5 minute
What is the freezing point of a fully charged lead-acid battery?
-90°F
The range markings of a battery hydrometer are
1.100 to 1.300
A specific gravity reading between ___ indicates a low state of charge
1.200 and 1.240
A specific gravity reading between ___ indicates a medium state of charge
1.240 and 1.275
When charged, a lead-acid battery electrolyte density is
1.275 - 1.300
A specific gravity reading between ___ indicates a high state of charge
1.275 and 1.300
You are reading a hydrometer at 40°F and your actual reading is 1.295, what is your actual specific gravity?
1.279
You are reading a hydrometer at 38°C and your actual reading is 1.285, what is your actual specific gravity?
1.293
How many volts per cell in a carbon-zinc battery?
1.5 volts
A 24 volt battery has how many cells?
12
How many volts does a freshly charged battery drop to due to internal resistance?
2.0
When recharging a battery, what is changed and stored?
Electrical energy supplied to the battery is changed to chemical energy
The framework of a lead-acid battery is made of.....
Lead and antimony
In a lead-acid battery, what is the positive plate made of?
Lead peroxide
How does current flow in a carbon-zinc battery?
Negative to positive
Primary cells
Non-rechargeable cells
Secondary cells
Rechargeable cells
Why cant a carbon-zinc battery be recharged?
Recharging cannot replace the zinc
What type of battery cells are used in aircraft?
Secondary
Which can be recharged, a primary cell or a secondary cell?
Secondary cell
Cells
Smaller power producing units that make up a battery
In a lead-acid battery, what is the negative plate made of?
Spongy lead
The active material attached to the framework is.....
Spongy lead and lead peroxide
In a lead-acid battery, what is the electrolyte made of?
Sulfuric acid and water
In a carbon-zinc battery, what are hydrogen ions attracted to?
The carbon rod
What may batteries provide in the event of a primary source failure?
The only source of power or reserve/standby
What does the amount of current in a carbon-zinc battery depend on?
The size of the cell
Mercury pellet
Used by a mercury battery in place of a carbon rod as an electrode
A Ni-Cad battery state of charge cannot be determined by what?
a hydrometer
What is a Ni-Cad battery positive plate made of?
a porous plaque on which nickel-hydroxide has been deposited
What is a Ni-Cad battery negative plate made of?
a porous plaque with cadmium-hydroxide deposits
The state of charge of a lead-acid battery depends on the condition of the
active material, primarily the plates
Connecting batteries in parallel increases the
ampere-hour capacity
What is the capacity of a battery rated in?
ampere-hours
What are batteries frequently used as in an aircraft?
as a dc power source
When should you do a hydrometer reading?
before adding water
The best range for reading a battery hydrometer is when the temperature is
between 70°F and 90°F degrees F
What can be used to clean lead-acid batteries?
bicarbonate soda, commonly known as baking soda and water
The cell separators are porous with vertical ribs that allow the electrolyte to
circulate freely and sediment to settle to the bottom.
Name two methods of charging a lead-acid battery
constant-current and constant-voltage
What should a lead-acid electrolyte level be at?
depending on the battery manufacturer, slightly above the top of the plates or up to the bottom of a ring in the cell filler neck
A lead-acid battery that is heavily discharged is
difficult to recharge due to high resistance caused by sulfate coating
What would you add to the electrolyte if it is found to be low?
distilled water
If baking soda is allowed into the electrolyte, what would happen?
it would neutralize the electrolyte
The negative plate of a lead-acid battery is coated with:
lead (Pb)
The positive plate of a lead-acid battery is coated with:
lead peroxide (PbO2)
A nearly totally discharged lead-acid battery is of
little use due to high internal resistance of the sulfate coating on the plates.
When charging a lead-acid battery, how is DC current passed?
opposite that of discharge current
When charging a lead-acid battery....
oxygen and hydrogen gases are produced in an explosive mixture
Hydrometer tests are made how often on aircraft batteries?
periodically
What is the purpose of the "vent plug"?
permits gasses to escape with the minimum of leakage, regardless of the aircraft's attitude
What keeps the positive and negative plate from touching and shorting the cell?
porous separators
What should you check for in battery vent lines?
proper attachment, cuts, kinks, or blockages
When charging the water content of the electrolyte is
reduced
What will a lead-acid battery do if it isnt kept clean?
self-discharge
How do you store Ni-Cad and lead-acid batteries?
separately
what are the advantages of a Ni-Cad battery?
short recharge time, excellent reliability, and good starting capability
The electrolyte density is measured as
specific gravity
A hydrometer measures the
specific gravity of a liquid
The liquid electrolyte is made of:
sulfuric acid (H2SO4) and water (H20)
Hydrometer readings may vary from actual specific gravity due to changes in
temperature
The non-spill vent cap on top of each cell is for:
testing the electrolyte and servicing the battery
The voltage of a lead-acid battery is dependant on
the cells that are connected in series to form a battery
The more dense the electrolyte
the higher the float in the hydrometer will be
During charging the lead sulfate is removed from the plates and
the sulfuric acid is again formed
During discharge, the lead sulfate on the plate becomes too
thick to allow a weakened electrolyte to reach the active material
The ampere-hour capacity depends on
total effective plate area
Connecting batteries in series increases the
total voltage
When assembled, a lead-acid battery positive plate is placed between:
two negative plates
What should you do if electrolyte from the lead-acid battery makes contact with your skin?
wash the area thoroughly with water and then apply baking soda
Can Ni-Cad and lead-acid batteries be interchanged?
yes
