Solar Glossary

AGM (Absorbed Glass Mat)
It is a type of battery construction that uses saturated absorbent glass mats in replacement to liquid or gelled electrolytes. These are more reliable when compared to flooded (liquid) and in terms of price.

Alternating Current (AC)
It is an electrical current that reverses the direction of flow. It usually powers electronic devices or appliances in the homes.

Alternator
A device used for producing alternating current electricity.

Amorphous Silicon
It is a thin-film solar PV cell material with structures made of glass instead of crystalline.

Ampere (A) or amp
Refers to the flow of electrons; a unit of electric current.

Array
Refers to a number if solar modules connected as a group to a single structure.

Array Current
Refers to an electrical current output of a PV array exposed to the sunlight.

Battery
A system that stores chemical energy and converts it directly to produce electrical energy.

Battery Capacity
Refers to the total number of ampere hours or Ah that can be outputted by a fully charged battery.

Battery Cell
The individual unit of battery that stores electrical energy. It is capable of furnishing a current to the external load.

Battery Charger
A device used to charge batteries by converting the AC voltage to DC voltage.

Battery Cycle Life
Refers to the capability of a battery to undergo a cycle of discharge and recharge several times before failing.

Battery self-discharge
Refers to the energy loss of a battery that is not placed under load.

Capacity
Refers to the maximum volume of TF cells or c-Si cells produced at a given period of time.

Cell
It is basic unit of a PV battery or module that contains electrolytes and electrodes found in a battery to generate electricity.

Cell Efficiency
It is the ratio of electrical energy that is generated by a photovoltaic cell placed under the full sun conditions to the energy sourced from the sun that falls upon the photovoltaic cells.

Charge
Refers to the process of inputting the electrical energy to the battery.

Charge Controller
It is a component that can control the flow of current from the battery subsystem and vice versa to protect that unit from overcharge and discharge. It is important that the battery gets the maximum state of charge and the most sustainable life. It may also be used to monitor the system’s performance and in providing your system protection. It is also referred to as the regulator.

Charge Rate
It is the measure of the current that is used in charging the battery as a proportion of its total capacity.

Crystalline Silicon
It is a type of material used in PV cells that is made from single crystal or polycrystalline ingot of silicon.

Current
Refers to the flow of electricity charge found in a conductor between two points with differences in electrical potential or voltage. It is usually measured in Amps.

Deep Cycle Battery
A type of battery designed with the purpose of regularly discharging 80% of its total capacity before it recharges.

Direct Radiation
It is light that traveled in a straight path from the sun’s direction. This is also referred to as the beam radiation. Any object that is in the path of direct radiation will cast a shadow on a clear day.

Discharge
The withdrawal of electrical energy from a battery.

Distributor
Refers to an individual or a company that offers wholesale PV products.

Efficiency
Refers to the ratio of output energy/power to input energy/power that is expressed in percentage.

Electric Current
It is the flow of electrons that is usually measured in Amps.

Electrical Grid
It is a network for distributing electricity in a large area.

Electricity
It is the movement of sub-atomic particles called electrons that is produced by a voltage that passes through a conductor.

Electrode
It is an electrically conductive material. It forms a part of an electrical device that is used in leading current into or out of a gas or liquid. In batteries, the electrodes are also commonly known as plates.

Energy
The power that is consumed multiplied to the duration of use.

Energy Density
It is the ratio of energy made available from a storage device for energy such as a battery to its volume with the unit Wh/m3 or weight with the unit of Wh/kg.

Fixed Tilt Array
It is a solar PV array that is set at fixed angles to the horizontal.

Flooded Cell Battery
It is a type of rechargeable battery. The plates of the flooded cell battery where the plates are immersed completely in liquid electrolyte. This type of battery is commonly used for cars or for independent and remote areas.

Gel-type Battery
The gel-type battery is a lead-acid battery where the gel immobilizes the electrolyte. It is commonly used in mobile installations and in instances when batteries will be exposed to high levels of vibration.

Generator
It is a mechanical device that is used in producing DC electricity. Electricity is produced by the coils of wire that passes through the magnetic fields found inside the generator. Generators may also refer to most alternating current generating sets.

Grid
It is a distribution network for an electrical utility.

Grid-Connected
It is a system that produces energy that is connected to the utility transmission grid. It is also referred to as grid-tied.

High Voltage Disconnect
An instance when the charge controller disconnects from the array in order to prevent the batteries from overcharging.

Incentive Programs
Refers to programs that give a project entitlement to profits.

Install Date
Refers to the period a manufacturing equipment installation is done whether it is a fab or a fab phase.

Installer
This refers to markets and customized PV systems for installation.

Inverter
The inverter acts as the converter for the DC power from the PV battery or array to AC power. These are used usually for stand alone systems or for grid-connected systems.

Irradiance
Refers to the solar power incident that occurs on a surface and is usually expressed in kilowatts per square meter. Irradiance is multiplied by time to get insulation.

Kilowatt (kW)
It is a unit for electrical power that is equal to 1000 watts.

Kilowatt-hour (kWh)
It is a unit used for the amount of energy that is derived from the power of 1000 watts that acts over a given period of 1 hour. A kilowatt-hour is equal to 3600 kJ.

kWh Output
It is estimated as the first year kilowatt hour output of a specific PV system. It is usually the output from which the PPA price is paid.

Liquid Electrolyte Battery
It is a type of battery that contains liquid solution of an electrolyte in a solvent such as sulfuric acid in water. It is also referred to as flooded battery.

Maintenance Free Battery
A type of sealed battery from which water cannot be added.

Maximum Power Point Tracker (MPPT)
The MPPT is a power conditioning unit that operates the PV generator automatically at its maximum power point regardless of the conditions. The Maximum Power Point Tracker usually increases the power delivered to a system by 10-40%. This depends on the climate and the state of charge of the battery.

Megawatt (MW)
It is a measurement of power that is equal to one million watts.

Megawatt-hour (MWh)
It is a measurement of power considering time or energy. A megawatt-hour is equal to a megawatt used over a period of one hour. In other terms a kilowatt used for 1000 hours.

Module Supplier
Individuals or companies that supply modules.

Module Type
Refers to a variety of modules such as c-Si:multi/mono, TF:a-Si/CdTe/CIGS, CPV

Monocrystalline Solar Cell
It is a type of solar cell created from a thin slice of a single large silicon crystal.

Multicrystalline
A type of material solidified at a given rate where many crystallites form. The atoms found within a single crystallite. These atoms are symmetrically arranged with a specific orientation; however the crystallites are arranged differently. Multicrystalline is also called polycrystalline.

MW
Megawatts.

Off-grid Applications
Applications that make use of stand-alone power generation systems. Batteries usually provide continuous power capability.

On-grid Applications
These are applications characterized with the PV system connected to the major electricity supplier; whereas, the excess energy produced is exported to the grid. Should there be a shortfall in PV output, electricity can be drawn from the grid.

Overcharge
Refers to a situation when a fully charged battery receives more current that can damage the battery.

Panel
A term often used in place of module.

Parallel-Connected
Refers to the method of connection; whereas, positive terminals are connected together while negative terminals are connected as well. The current output increases but the voltage remains at a stable point.

Peak Sun Hours
The number of hours in a day when the solar irradiance averages to 1000 W/m2

Photovoltaic (PV)
Any type of device that produces free electrons when given exposure to light.

Photovoltaic (PV) Array
Refers to the number of PV modules that are connected on a single structure.

Photovoltaic (PV) Cell
It is the smallest element of a PV module that converts light into electrical energy which produces DC current and voltage

Photovoltaic (PV) Module
Refers to a single assembled solar cells and ancillary parts which compose of interconnections and terminals that are intended to produce DC power under un-concentrated sunlight.

Photovoltaic (PV) Panel
A term used commonly in replacement for PV module.

Polycrystalline Cell
A silicon wafer developed to create solar PV cells that consist of many crystals when compared to single crystal silicon.

Power
Refers to the rate of doing work. It is usually expressed in the unit Watts (W)

PV
The abbreviation for photovoltaic.

PV Array
Refers to two or more PV panels that are wired in parallels or series.

PV Components
Refers to the individual PV system parts.

PV System
The final result of the combination of the PV components that generates solar electricity.

Renewable Energy
A type of energy produced from a renewable source.

Series-Connected
It is a type of connection where positive terminals of a device is connected to the negative terminals of another device.

Silicon
Bears the symbol Si. It is the chemical element with the atomic number 14. It is characterized by its dark gray semi-metal features.

Solar Energy
Refers to energy sourced from the sun.

Solar Module
A device that uses photovoltaic effect to convert light sourced from the sun into DC electricity.

Solar Power
The electricity produced by the sunlight through direct conversion by using photovoltaic panels or indirect conversion through the solar-thermal process.

Stand-Alone
Refers to a type of PV system that produces electricity without the need to be connected to a grid

Storage
Refers to the act of storing energy in a battery or battery stack.

Storage Density
Refers to the capacity of a battery measured in amp-hours compared to its weight. It is usually measured in watt-hours per kilogram.

Thin Film
It is a layer of semiconductor materials which is usually a few microns thick that are used in making photovoltaic cells.

Tracker
Refers to any type of device that directs a PV array towards the direction of the sun.

Tracking Array
Refers to a PV array moved to follow the direction of the sun to maintain the surface’s maximum incident solar radiation.

Utility-interactive Inverter
A type of inverter that can only be operated when connected to a utility grid an output voltage frequency that is fully synchronized with utility power.

Volt
The electric potential and potential unit difference. It is the amount of work performed per unit charge in a moving charge from one point to another.

Voltage
It is the measurement unit for electrical pressure of electricity. It is uses the unit volts (V).

Voltage Drop
Refers to the voltage lost because of the resistance of a conductor.

Voltage Regulator
A device that regulates the operating voltage of a PV array.

Watt (W)
A unit of measurement for electrical power. 1 watt is equal to 1 Joule.

Watt hour (Wh)
It is a unit of energy equivalent to a watt of power used for a period of one hour.

Watt/kilowatt/megawatt/gigawatt
These are the electrical power units that increases in scale by 1000