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Alternating Current (AC)
An electric current
that reverses direction at regular intervals.
Sources of alternating current are shore
power, generator power, inverter power or
household current.
Ampere (Amp, A)
The unit of measure of
electron flow rate of current through a circuit.
Ampere-hour (Amp-Hr., Ah)
A unit of
measure for a battery’s electrical storage
capacity, obtained by multiplying the current in
amperes by the time in hours of discharge
(Example: a battery which delivers 5 amperes
for 20 hours delivers 5 amperes times 20
hours, or 100 Ah of capacity.)
Ampere-Hour Capacity
The ability of a fully
charged battery to deliver a specified quantity
of electricity (Amp-Hr., Ah) at a given rate
(Amp, A) over a definite period of time (Hr.).
The capacity of a battery depends upon a
number of factors such as: active material,
weight, density, adhesion to grid, number,
design and dimensions of plates, plate spacing
design of separators, specific gravity and
quantity of available electrolyte, grid alloys, final
limiting voltage, discharge rate, temperature,
internal and external resistance, age and life of
the battery (bank).
AGM (Absorbed Glass Mat) Battery
A lead
acid, maintenance-free battery.
AWG (American Wire Gauge)
A standard
used to measure the size of wire.
Circuit
An electric circuit is the path of an
electric current. A closed circuit has a
complete path. An open circuit has a broken or
disconnected path.
Circuit (Series)
A circuit which has only one
path for the current to flow. Batteries arranged
in series are connected with the negative of the
GLOSSARY
first to the positive of the second, negative of
the second to the positive of the third, etc. If
two 6-volt batteries of 50 ampere hours
capacity are connected in series, the circuit
voltage is equal to the sum of the two battery
voltages, or 12 volts, and the ampere-hour
capacity of the combination is 50 ampere
hours.
Circuit (Parallel)
A circuit which provides
more than one path for current flow. A parallel
arrangement of batteries (of like voltage and
capacity) would have all positive terminals
connected to a conductor and all negative
terminals connected to another conductor. If
two 12-volt batteries of 50 ampere-hour
capacity each are connected in parallel, the
circuit voltage is 12 volts, and the ampere-hour
capacity of the combination is 100 ampere
hours.
Current
The rate of flow of electricity or the
movement rate of electrons along a conductor.
It is comparable to the flow of a stream of water.
The unit of measure for current is ampere.
Cycle
In a battery, one discharge plus one
recharge equals one cycle.
Direct Current
(DC) Current that flows
continuously in one direction such as that from
batteries, photovoltaics, alternators, chargers
and DC generators.
