H8 Flashcards
Cell
basic unit that converts chemical energy to electrical energy
Cells are divided into two fundamental types
Primary cells
Secondary cells
In a primary cell discharge
results in a progressive destruction of one or both of the electrodes and when full discharged the chemical reaction is irreversible.
The most common type of primary cell is the
dry cell
List the most common types of dry cell
Carbon zinc (Leclanche) Zinc Chloride Alkaline Mercury Silver oxide Lithium
Carbon Zinc (Leclanche)
most common because of low cost
1.5 V
optimal temp of 20 degrees C
general purpose
Zinc-chloride
the heavy duty cell up to 50% more energy
1.5 V
Alkaline Cell
10 times more energy that Carbon Zinc
long shelf life but more expensive
1.5 V
Silver-oxide cell
button configuration
1.6 V
Mercury cells
button configuration
poor performance at cold temps
1.35 V
Lithium cells
wide range of working temps
long shelf life
3 V
Three types of secondary storage batteries
lead-acid
Nickel-iron
Nickel-cadmium
Nickel-iron
Edison battery
if stored should be discharged, short-ccted and left in that condition for the storage period.
Fully charged should be about 1.37 V per cell
Nickel-cadmium
electrolyte has a relative density of about 1200 but doesn’t change during charge or discharge
1.2V
uses Constant-current method charging
Battery maintenance and testing
measure the relative density of pilot cells
record hydrometer readings
check electrolyte levels
measure cell voltages with battery on float charge
Clean
