GLOSSARY OF TERMS
Absorption Charge
The second stage of three-stage battery charging. Voltage remains constant and current tapers as internal
battery resistance increases during charging. (Ensures complete charging.)
Alternating Current (AC)
The type of electrical power supplied by utilities or made when a generator is run. The unique
characteristic of this form of electricity is that it reverses direction at regular intervals. For example, 240
Vac 50 Hz. power reverses flow 50 times a second, hence the rating 50 Hz. (cycles).
Amp (Ampere)
Measurement of the flow of electrical current. One amp is equal to the electric force of one volt acting
across the resistance of one ohm.
Amp Hour
One amp of electrical current flowing for one hour. Expresses the relationship between current (amps)
and time. (OHMS law A =V/R)
Array
A group of solar electric modules or batteries wired together.
Bulk Charge
The first stage of three-stage battery charging. Current is sent to batteries at the maximum rate they will
accept while voltage rises to full charge level.
Current
The rate of flow of electrical charge. The flow of amps is often expressed as current.
Direct Current (DC)
The type of electricity stored in batteries and generated by solar electric devices. Direct Current flows in
a single direction.
Electrolyte
A conductive medium in which the flow of electricity takes place; this is the liquid found inside storage
batteries.
Float Charge
The third stage of three-stage battery charging. After batteries reach full charge, charging voltage is
reduced to a lower level to reduce gassing (boiling of the electrolyte) and prolong battery life. This is
often referred to as a maintenance charge, since rather than charging a battery, it keeps an already-
charged battery from self-discharging.
Ground Fault Protection (GFP)
A circuit protection device that prevents the flow of electrical current to earth if a short circuit is present.
Usually required in wet locations e.g. for outdoor, kitchen and bathroom circuits.
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