Electricity 1: Battery Basics and Lead Acid Batteries

What is a battery?

A portable power source

How does a battery make energy?

It used a chemical reaction to make energy.

What is the basic unit of a battery?

The cell

What are the 3 components of a cell?

2 different metals called electrodes and 1 chemical solution called an electrolyte?

What is an electrolyte?

solution of water and a chemical compound that will conduct electric current within the cell

What are the 2 types of cell?

Dry-cell and wet cell

What are the two classes of batteries?

Primary cell and secondary cell

What is a primary cell?

a cell that convert chemical energy to electrical energy directly, using materials within the cell to start the action.

Can a primary cell be recharged?

NO, it cannot be recharged

What is a secondary cell?

A cell that must first be charged with electrical energy before it can convert chemical energy to electrical energy.

Can secondary cells be recharged?

YES, it can be recharged

How does the electrolyte react with te two different electrodes.

It reacts oppositely. It caused one electrode to develop a positive charge and loose electrons, and the other to build up electrons and develop a negative charge

What are the positive plates made of in a lead acid battery?

Lead dioxide

What are the negative plates made of in a lead acid battery?

spongy/soft lead

What is the electrolyte in a lead acid battery?

70/30 mix of sulfuric acid and distilled water

What is charge of a lead acid cell?

2.2 volts rated at 2 volts

What is the amp hour rating?

a measure for the battery capacity. determined by total effective plate area.

What does connecting batteries in paralell increase?

The amp hour rating

What does connecting the battery in series increase?

the total voltage

What is the life cycle of a battery?

The number of complete charge/discharge cycles a battery can perform before its normal charge capacity falls below 80%

What are 3 factors that can shorten service life of a battery?

Over-charging

too rapid charging

too rapid discharging

What indicates the state of charge in a lead acid battery?

The electrolyte

How do you check the charge of a battery from its electrolyte?

By using a hydrometer to check its specific gravity

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

1.3

When should SG be checked?

Before adding any water to the battery

To charge a battery, charging current must be passed in what direction of discharge current flow?

The opposite direction

When charging the battery the charging source should be a larger amount than the battery OCV

TRUE

What is the constant voltage charge method?

Current flow will be high at the beginning and tapers off as the battery charges

What is the constant current method?

Current remains constant during the charge. This takes longer and increase the chance of overcharging.

During charging of a lead acid battery always...

Loosen the vent caps and remove during charging

In a sealed lead acid (VRLA) battery where does the electrolyte go?

Into a glass mat separator

Do sealed lead acid batteries work the same way as flooded lead acid batteries?

Yes

When a sealed lead acid/VRLA battery charges what happens with the gas process?

The oxygen combines chemically with the lead at the negative plates in the presence of sulphuric acid to form lead sulfate and water. This oxygen recombination suppress generation of hydrogen. There is no water loss and gasses can be vented if the battery is overcharged.

Why are SLAs gaining in use over flooded lead acids or Ni-cads

They perform well in extended standby application, like emergency batteries. They also can be designed to alert technicians if the battery is failing

Why must planes have battery vent systems?

The vent system removes gases and acid fumes from the battery to reduce fire hazards and eliminate damage to the structure.

How does an aircraft vent system work?

Outside air is introduced through a vent tube to the interior of the battery case. After passing over the top of the battery, air, battery gasses, and acid fumes are carried through another tube to the battery sump, then to the outside of the airplane.

What solution should be made to neutralize and clean battery acid?

Baking soda and water