Aviation General Batteries

What instrument is used to measure the specific gravity of the electrolyte in a lead-acid battery?

A hydrometer.

What electrolyte is used in a lead-acid battery?

A mixture of sulfuric acid and water.

What is used to neutralize spilled electrolyte from a lead-acid battery?

A solution of bicarbonate of soda and water.

What is used to neutralize spilled electrolyte from nickel-cadmium battery?

A solution of boric acid and water.

What is the specific gravity of a fully charged lead-acid battery?

Between 1.275 and 1.300

What is the range of temperatures of the electrolyte in a lead-acid battery that does not require a correction when measuring its specific gravity?

Between 70F and 90F.

How may thermal runaway be prevented?

By carefully monitoring the temperature of the middle cells and controlling the charging current to prevent an excess of current flowing into the battery.

How is it possible to know when a nickel-cadmium battery is fully charged?

Completely discharge the battery and give it a constant-current charge to 140% of the ampere-hour capacity.

How high should the electrolyte level be in a properly serviced lead-acid battery?

Only up to the level of the indicator in the cell.

How do you treat a lead-acid battery compartment to protect it from corrosion?

Paint it with an asphaltic (tar-base) paint or with a polyurethane enamel.

What is the electrolyte used in a nickel-cadmium battery?

Potassium hydroxide and water.

What is the open -circuit voltage of a lead-acid battery cell?

2.1 volts

How many cells are there in a 24-volt lead acid battery?

12 cells

Is the electrolyte level of a nickel-cadmium battery lowest when the battery is fully charged or discharged?

Fully discharged.

What gases are released when a lead-acid battery is being charged?

Hydrogen and Oxygen

In what units is a battery capacity expressed?

In ampere-hours.

Does the specific gravity of a the electrolyte in a lead-acid battery increase or decrease as the battery becomes discharged?

It decreases.

Why is a hydrometer not used to measure the state of charge of a nickel-cadmium battery?

The electrolyte of a nickel-cadmium battery does not enter into the chemical changes that occur when the battery is charged or discharged. Its specific gravity does not change appreciably.

What is the thermal runway?

The large current flow allowed by the low internal resistance causes the middle cells to produce more heat than they can dissipate. The heat further lowers the internal resistance so more current can flow; this continues until the battery destroys itself.

What is a result of a cell imbalance in a nickel-cadmium battery?

The low internal resistance allows current to flow between the unbalanced cells and generate heat.

What is meant by the capacity rating of a lead-acid battery?

The number of hours a battery can supply a given current flow.

What precautions should be taken in the maintenance shop where both lead-acid and nickel-cadmium batteries are serviced?

The two types of batteries should be kept separate, and the tools used on one type should not be used on the other.

Why is the closed-circuit voltage of a lead-acid battery lower than its open-circuit voltage?

Voltage is dropped across the internal resistance of the battery.