Go Power! GP-PWM-25 - Manual (Page 20)

Owner’s Manual | GP-PWM-25 Regulator
20
© 2010 Carmanah Technologies Corporation
Last revised March 2010
10.0 Glossary
Ampere: A unit of electrical current. Designates the number of electrons flowing per second through a
conductive material.
Array: One or more photovoltaic (PV) modules electrically connected to produce a single electrical output.
Battery: Two or more electrochemical cells connected to provide energy storage.
May be used to designate one cell. PV system batteries may be “sealed” or “wet acid”.
Charge Controller: The PV system component that controls the battery’s state of charge. It may also provide
other system control functions. Also referred to as a regulator.
Charge Rate: The current applied to a battery to restore its energy capacity. The battery manufacturer will
usually have a recommended charge rate for their product. The rate is typically 10 –20 percent of the amp hour
capacity at the 20-hour rate.
Current: DC or Direct Current is the type of electron flow provided by a battery or solar cell, which flows in one
direction. The unit for current is ampere or amp for short and designated by the letter A.
Deep Cycle Battery: Batteries that are designed to discharge as much as 80% of their capacity as opposed to
engine-starting or “shallow cycle” batteries which are designed for heavy cranking but will not stand up to
repeated deep discharges.
Equalization: The process that equalizes the specific gravity of all the cells in a battery by means of a
controlled overcharge that breaks down sulfation on the battery plates. Most inverter/chargers and some charge
controllers are equipped with this feature.
Maximum Power: Also referred to as peak power. The point of a solar array, panel or module output where the
product of “Imp” and “Vmp” (“Pmax”, measured in watts) is maximized. The points used to calculate Pmax are
Imp (current @ max power) and Vmp (voltage @ max power).
Solar Module: A number of solar cells electrically connected, and protected from the environment usually by
an aluminum frame covered with a pane of glass. A module is self-contained and not sub dividable, therefore
providing a single electrical output.
Open-Circuit Voltage (Voc): Refers to a photovoltaic device’s voltage potential when it is disconnected from
the rest of the PV system.
Parallel Connection: Electrical connection where the positive terminals of a number of devices are connected
together, as are their negative terminals. The output voltage is usually limited to the device with the lowest
voltage, and the total current is the sum of the current of all the devices.
Photovoltaic (PV): Capable of producing a voltage when exposed to radiant energy, especially light.
Sealed Batteries: Electrolyte will not spill out and gassing is kept to a minimum. A sealed battery is
maintenance free and may be installed in several orientations. GEL and AGM are two common types of sealed
batteries.
Series Connection: Electrical connection where the positive terminal of one device is attached to the negative
terminal of the next in a series string; in this connection, the string voltage is the sum of the device voltages and
the string current is limited to the current of the least productive device in the string.
Short-Circuit Current (Isc): Refers to a photovoltaic device’s current output when the positive terminal is
directly connected to the negative terminal.
State of Charge (SOC): The percentage of energy in a battery referenced to its nominal full capacity.
Sulfation: The formation of lead sulfate crystals on the plates of a lead-acid battery. Normally used to refer to
large sulfate crystals, rather than small crystals formed in normal battery operation. The plates of a battery will
sulfate if left in a partially charged state, causing reduced battery capacity and shortening the life of the battery.
If caught in time, equalization will remove the buildup of sulfation.
Voltage: The electrical potential between two points. Voltage is analogous to water pressure in that it pushes
the electrons or current through a conductor. The unit for voltage is volt and designated by the letter V.
Wet Acid or Flooded Batteries: The most common type of PV battery. Battery caps may be removed to
expose the electrolyte liquid inside the battery. Need proper ventilation due to gassing and may need to be
topped up with distilled water at regular intervals.