Go Power! GP-RV-20 - Manual (Page 9)

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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.
Cycle: One battery cycle equals one discharge and one charge.
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.
Depth of Discharge: A measure of how much energy has been withdrawn from a
battery, expressed as a percentage of full capacity. A 100 Ahr battery from which 30
Ahr has been withdrawn has undergone a 30% depth of discharge (DOD). This term is
the inverse of state of charge (SOC); the example battery would be at 70% SOC.
Diode: A semi-conductor device that allows current to flow in one direction only.
“Blocking diodes” and “isolation diodes” are standard diodes that have specific
applications.
Electrolyte: Battery acid.
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. Usually performed only on flooded batteries.
Flooded or Wet Cell Batteries: The most common type of PV battery. Battery caps
may be removed to expose the electrolyte inside the battery. Need proper ventilation
due to gassing and may need to be topped up with distilled water at regular intervals.
Grid-Connected: A power system interconnected with the grid (or mains) of the local
electric utility. Also referred to as utility-interactive or grid-tie.
Hybrid System: A power system consisting of two or more energy sources (e.g., a
PV array and a wind generator).
Hydrometer: A device used to measure the specific gravity (SG) of the electrolyte in
a flooded battery. A very accurate way to see the true charge of a battery.
Insolation: The solar energy received at a place over a given period. May be expressed
as sunhours per day, watts per square meter per hour, or any number of other units.
Inverter: A device that converts DC electricity to AC.
Isolation Diode: A diode application that prevents one segment of an array from
interacting with another array segment. Usually used in situations where two parts of
an array are facing in different directions therefore one part of an array may experience
shading while the other does not. Prevents array energy from flowing backwards through
a low voltage string of the array. May also serve the function of blocking diode.
Maximum Power (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).
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.
NOCT (Nominal Operating Cell Temperature): the temperature at which PV cells
in a module operate under Standard Operating Conditions (SOC), which are: irradiance
of 0.8 kW/m2, 20ºC ambient temperature, and average wind speed of 1 m/s, with the
wind oriented parallel to the plane of the array, and all sides of the array fully exposed
to the wind.
Open-Circuit Voltage (Voc): Refers to a photovoltaic device’s voltage potential when
it is disconnected from the rest of the PV system.
Panel: A group of photovoltaic modules (or single module) mechanically mounted on
a single frame.