Alternative Energy Glossary

A

AC:
Acronym for: Alternating Current: See Alternating Current

AGM Battery:
Acronym for: Absorbed Glass Mat Battery:
GM batteries are sealed batteries that have the electrolyte permeated in a fiberglass material rather than suspended as a liquid. The advantage of the permeation design is that there is no out gassing of hydrogen and oxygen. The disadvantage of AGM Batteries is fewer charging, meaning they don't last as long as flooded batteries. AGM Batteries are one of two types of “Sealed” or Valve-Regulated Lead-Acid (VRLA) batteries.  See Alternating Current

Alternating Current:
Acronym: AC or also known as VAC.
Alternating Current has a regular, change of the flow direction or an alternating direction of the flow of electrons. The rate of this change of alternating direction is known as frequency. In the U.S., AC is standardized at a Frequency of 60 Hertz (cycles per second), meaning the direction of the electron flow changes 60 times per second. In Europe, AC is standardized at a Frequency of 50 Hz.


Altitude Angle:
The angle created between the horizon and a line drawn through the center of the sun. This angle is expressed in degrees (°) between 0 and 90. The angle changes constantly at a constant rate throughout the day as the sun arcs across the sky. The optimum tilt angle for a solar array at any given moment is factored on the altitude angle. See TILT ANGLE.


Amorphous Silicon Photovoltaic cell:
Synonymous with Thin-Film Cells:
A Silicon Photovoltaic (PV) Cell type that is non-crystalline and not based on individual cells. Less efficient than crystalline cellular types, amorphous cell types are usually less expensive to manufacture. They can be made into non-flat or even flexible, modules. See also Photovoltaic Cell, Thin Film.

Ampere or Amp:
Unit of measure for electrical current. The Amp is a rate of current flow.

Amp-Hour Capacity:
The measurement of stored energy in a battery. This rating is based on the ability of a fully charged battery to deliver current at a specified rate (Amp, A) over a specific period of time (Hour). A battery with a capacity of 1 amp-hour should be able to continuously supply a current of 1 amp to a load for exactly 1 hour, or 2 amps for 1/2 hour, etc., before becoming completely discharged. The actual capacity of a battery depends upon many factors, including type and construction of the battery, discharge rate, temperature and age of the battery. See Ampere

Array:
Synonymous with PV Array:
A solar Photovoltaic (PV) array is a collection of one or more solar modules combined to form a single electrical output. Photovoltaic array modules are wired in SERIES and/or PARALLEL to produce a specified total VOLTAGE and AMPERAGE. See PV ARRAY.

Array Mount:
The mounting structure used to support a PV ARRAY. Usually consisting of a stiff frame made of aluminum and/or steel. Common types include TOP-OF-POLE or SIDE-OF-POLE, rooftop FLUSH-MOUNT, ground or roof TILT-UP mounts.

AWG:
Acronym for American Wire Gauge:
This is a set standard for wire and cable diameter measurement. The higher the AWG number, the smaller the wire diameter. This wire gauge standard is based on No. 36 AWG being 0.005 inches in diameter, and No. 0000 (4/0 or four aught) being 0.46 inches in diameter. The ratio of these diameters is 92, and there are 40 gauge sizes from No. 36 to No. 0000 (4/0 or four aught), or 39 steps. In the U.S electrical industry, conductors larger than 4/0 AWG are generally identified by the area in thousands of circular mils.

Azimuth:
Refers to the angle of a PV ARRAY from a given point calculated on a vertical axis. This orientation is expressed in degrees (°). Azimuth is the left or right angle formed from a given point. Since the sun arcs across the sky, the most common Azimuth orientation in the Northern hemisphere is to aim the PV array toward TRUE SOUTH.


B

Ballast Mount:
A type of PV ARRAY MOUNT that does not use penetrating anchors (screws, etc.) for attachment, but instead utilizes weight or ballast to hold the PV ARRAY in place. Ballast mounts are most commonly used on flat-roof commercial installations where there’s no protruding structure to attach to and attaching to the flat roof itself might be prohibited because of potential leaks. See also GROUND/ROOF MOUNT.


Battery:
Synonymous with storage cell or wet cell:
 A device used for chemical storage of electrical potential energy. Most batteries are commonly constructed of two compounds or elements of opposing electrical properties. Batteries release their potential energy as DC electricity. Batteries used in most renewable energy systems are generally DEEP CYCLE batteries.

Battery Separator:
Synonymous with Separator:
A divider made of a non-conducting porous material that is placed in between the positive and negative plates in a battery cell, allowing current to flow through it while preventing direct contact between the plates which would create a short circuit.

#BEV:
Acronym for Battery Electric Vehicle

Booster Pump:
A pump used to increase pressure in a water line.

Bulk Charge:
The first stage of battery charging. Current is applied to the batteries at the maximum rate they will accept until voltage rises to full charge level.

C

Cell Technology:
Monocrystalline: These cells are made from very thin wafers of purified silicon. They offer the highest efficiency of crystalline silicon module types.
Polycrystalline: These cells are made from very thin wafers of purified silicon grown in multi-crystal ingots. They have similar characteristics to monocrystalline cells, they have a slightly lower efficiency and are usually slightly cheaper to produce) price.
String Ribbon: Similar to polycrystalline technology, slightly lower in efficiency. These cells are manufactured by pulling two "strings" (wires) up from a vat of molten silicon, between which a film of the molten material rises, suspended on the wires. String ribbon cells contain less silicon than crystalline cells and tend to be slightly less expensesive. Aorphous-Si (acronym: A-Si): The term "thin-film" is often loosely applied to these cells but can also include elements other than. A-Si. The efficiencies of A-Si, and thin-film cells in general are significantly lower. Copper Indium Gallium di-Selenide: (acronym: C.I.G.S.) a type of a thin-film PV technology that does not use silicon to produce the photovoltaic electric current.

Centrifugal Pump:
A type of pump that moves water by spinning it with an impeller. Water is usually drawn into the middle of the pump and is spun and pushed out by centrifugal force.

Charge Controller:
Synonymous with Charge Regulator or Charger:
An electrical device which charges, monitors and regulates the charge level of the batteries. The device can control electrical CURRENT, from an AC or DC source, into a BATTERY for the purpose of restoring the battery's charge. Charge controllers prevent battery over-charging and prevent battery discharge, in reverse, toward the charging source, like the photo cell modules. They can be designed on various technologies. More advanced charge controllers use Pulse Width Modulation (PWM) or Multiple Power Point Tracking (MPPT). They are sized based on Amperage and Voltage capacities.

Charge Cycles:
The measure of a batteries useful life. One cycle consists of the complete discharge and recharge of the battery. The number of cycles possible from a battery is directly related to the DEPTH OF DISCHARGE, as well as ambient temperature.

Charger:
Synonymous with Charge Controller:
An electrical device which charges, monitors and regulates the charge level of the batteries. The device can control electrical CURRENT, from an AC or DC source, into a BATTERY for the purpose of restoring the battery's charge. Charge controllers prevent battery over-charging and prevent battery discharge, in reverse, toward the charging source, like the photo cell modules. They can be designed on various technologies. More advanced charge controllers use Pulse Width Modulation (PWM) or Multiple Power Point Tracking (MPPT). They are sized based on Amperage and Voltage capacities.

Charging States:
Bulk, Absorb, Float or Trickle and Equalization Charge.

Check Valve:
A type of automatic valve that allows water or any other fluid to flow in only one direction. Check valves are often used in solar water heating systems where the flow of water is to be directed in one direction through the plumbing loop and no reverse in direction of the flow is wanted, like when a pump stops, the water cannot backflow.

Circuit:
Is an electrical pathway of conductors or wires for electrical current.

Cloud Effect:
Synonymous with Edge-of-Cloud Effect:
As a cloud begins to cover the sun or when the sun is emerging from behind a cloud, there is a sudden burst of energy that produces a spike in power which is higher than normal. This is caused by light refraction. This phenomenon must be figured into system design and sizing in order to avoid current spikes that could damage system components.

Combiner Box:
A weather proof enclosure or box used to protect electrical connections between multiple components in the.

Conductor:
Any wire or object designed to carry the flow of electricity

Connector Type:
Various types of connectors for connecting wires from solar modules and other components. Most modules use one of four types: 1. A Junction Box or J-Box.: A user accessible junction box with screw terminals for landing wiring connections. 2. MC1 connector. MC1 connectors are the most common. The MC refers to Multi-Contact. MC1/Solarline 1. These connectors are outdoor rated weather tight connectors, that come as male and female. 3. MC2 Locking Connector. MC2 are similar to MC1 but offer locking tabs to ensure a more secure connection. 4. SAE Plug. SAE is an acronym for Society of Automotive Engineers. These connectors are a snug fitting, male/female, two prong type based on an automotive industry standard.

Converter or Power Converter:
Synonymous with  Switched Mode Power Supply:
An electronic device for that regulates current at a set voltage.

Critical Low Voltage:
Acronym is CLV:
This is the absolute low voltage level that a battery(s) should be discharged. Deep discharging beyond this level could permanently damage the battery.

Crystalline or Mono-Crystalline or Poly-Crystalline Silicon Cell:
A type of PV cell or wafer which is made from a highly purified silicon crystal. Mono-crystalline silicon cells have efficiency ratings between 15-17%; poly-crystalline cells' efficiencies range from 13-16%.
See Cell Technology.

Current:
Is the flow of electricity or electrons through a wire. Current is measured in Amperes or Amps.


D

Dankoff Foot Valve:
Synonymous with Foot Valve:
This is a type of check valve that usually has a built in strainer. This type of valve is placed at the point of liquid intake and prevents the pump from loosing prime. The strainer protects the pump and system from damage caused by debris being sucked into the system. See also: CHECK VALVE

Deep Cycle:
A Battery that is designed to discharge 80 percent of it’s capacity before recharging. Discharge is usually at a even steady rate, as opposed to car batteries that give a quick surge of electricity to turn the starter. This type of battery well designed for use in renewable energy systems.

Depth of Discharge:
Acronym is DOD or DoD:
The level of energy discharge that a battery is subjected. DoD is expressed as a percent of total capacity. 0% DOD would indicate “No Discharge” or a fully charged battery, a 70% DOD would indicate a battery that has 30% of it’s charge remaining. Batteries have a recommended DOD level which is usually 50%. See STATE OF CHARGE

Diaphragm Pump:
Synonymous with Membrane Pump:
This type of pump uses reciprocating flexible diaphragms and check valves to push the water in one direction. This type of pump is classified as a positive displacement pump.

Direct Current:
Also know as Galvanic Current:
Acronym is DC or VDC:
The electrical current or electrons move in one consistent direction. The direction of the current or polarity is fixed and defined as positive (+) and negative (-). This is type of electrical currnt produced by photovoltaic modules. Batteries also discharge DC current. See VOLTAGE, AMPERAGE. e.g. 12 VDC

Disconnect:
This is an on/off switch, usually considered a safty swith to make sure that the system or device is isolated from the power source. They can be fused or non-fused and come in many different types and amperage ratings. Types include knife-throw, removable link, standard breaker type switch, etc.

E

Edge-of-Cloud Effect:
Synonymous with Cloud Effect:
As a cloud begins to cover the sun or when the sun is emerging from behind a cloud, there is a sudden burst of energy that produces a spike in power which is higher than normal. This is caused by light refraction. This phenomenon must be figured into system design and sizing in order to avoid current spikes that could damage system components.

Efficiency:
Is a measurement as a percentage or ratio of the output to the input of any system or equipment. Example: An example would be an electric motor that is 80% efficient converts 80% of the input energy into useful work. The remaining 20% is lost as heat.

EGS:
Acronym for Engineered Geothermal System:
Originally know as HDR or Hot Dry Rock technology. This geothermal technique involves drilling two wells to depths as deep as 30,000 feet where temperatures can reach 392- 662 degrees Fahrenheit (200-350 degrees Celsius). The first well is called an injection well and is used to pump cold fluid down and the second well is called the production well and is used to bring the heated fluid to the surface. The two wells are not directly connected, but through a process of high pressure fracturing of the basement rock, the fluid passes through these fractures and is heated. Once the heated fluid reaches the surface it goes through a heat exchanger where it transfers the heat to a working fluid with a low boiling point, thus transformed into vapor or (steam) and is used to power turbines and generate electricity.

Electrolyte:
In batteries this is the part that is usually a liquid or semi-liquid, know as an ionic solution. This is a solution of free ions which acts as an electrical conductive medium that carries a charge between the plates of a battery. In lead acid batteries, the plates are made of lead and the electrolyte liquid between them is a dilute solution of sulfuric acid (H2SO4) and water.

Energy:
This is the ability to do work. There are many types of energy, but in reference to electricity. Electricity is a form of kinetic energy. Electrical energy is measured in Watt-hours. 1,000 Watt-Hours = 1 kilowatt-hour (symbol is: kWh). Electrical energy in batteries is measured as Ampere-hours or Amp-hours (Ah).

Engineered Geothermal System:
Acronym is EGS:
Originally know as HDR or Hot Dry Rock technology. This geothermal technique involves drilling two wells to depths as deep as 30,000 feet where temperatures can reach 392- 662 degrees Fahrenheit (200-350 degrees Celsius). The first well is called an injection well and is used to pump cold fluid down and the second well is called the production well and is used to bring the heated fluid to the surface. The two wells are not directly connected, but through a process of high pressure fracturing of the basement rock, the fluid passes through these fractures and is heated. Once the heated fluid reaches the surface it goes through a heat exchanger where it transfers the heat to a working fluid with a low boiling point, thus transformed into vapor or (steam) and is used to power turbines and generate electricity.


Equalization charge:
This is a process where an increased voltage is used to charge a battery for a short interval. This causes gassing that re-mixes the electrolyte solution. This process is most commonly used in flooded lead acid batteries. This process reduces the lead sulphate build up on the plates, thereby extending the life of the battery.

F

Fixed array or Fixed tilt array:
Refers to the tilt angle of a flat-plate solar ARRAY, in relation to the ground, being static and not adjustable. Some mounts, such as pole-top mounts and roof/ground mounts with adjustable legs, allow seasonal tilt adjustment. The rest are installed at a fixed tilt angle, usually equal to the location latitude, in degrees from horizontal.

#FLA:
Acronym for Flooded Lead Acid Battery:

Float Charge or Trickle Charge:
Is a low voltage charge that compensates for the self discharge or leakage of a battery.

Flooded Lead-Acid Battery:
Acronym is FLA:
These batteries chemically store electrical energy utilizing an electrolyte solution, usually consisting of sulphuric acid and water between lead plates. This type of battery is the most common and least expensive. Flooded Lead-Acid Batteries outgas hydrogen and oxygen gasses and must be vented..

Flow Rate:
Referring to systems that containing water. This is the rate at which water moves through the system. It is measured in gallon per minutes (gpm) or liters per minute (l/m).

Flush Mount:
A type of PV ARRAY MOUNT used on rooftops. PV Modules are mounted flat or parallel to the roof surface

Foot Valve:
Synonymous with Dankoff Foot Valve:
This is a type of check valve that usually has a built in strainer. This type of valve is placed at the point of liquid intake and prevents the pump from loosing prime. The strainer protects the pump and system from damage caused by debris being sucked into the system. See also: CHECK VALVE

G

Galvanic Current:
See Direct Current.

Gel Cell Battery:
In this type of battery the electrolyte has a compound added, usually silica to thicken or stiffen it from a liquid form to more of a gel. This is one of two types of “Sealed” or Valve Regulated Lead Acid batteries.

Geothermal Energy:
Is energy generated from heat below the Earth’s surface.

GFCI:
Acronym for Ground Fault Circuit Interrupter:
Also know as a RCD or Residential Circuit Breaker or RCCD Residential Current Circuit Breaker outside the United States and Canada. It is an electrical safety device that rapidly turns off a circuit when measured current balance between two conductors is different and exceeds a predetermined value (typically 5- 30 milliamperes). If the current is not equal in both lines, then there is leakage of the current somewhere else and the circuit is automatically shut off almost instantly. Most GFCI’s upon detection of the leakage shut off the circuit within 25-40 milliseconds. This is fast enough to prevent the leaking current from affecting the human heart. These GFCI’s come in different forms: Receptacle types, Circuit Breaker types and portable types.

Glass Mat or Absorbed Glass Mat Battery:
Acronym is AGM:
AGM batteries, are sealed batteries that have the electrolyte permeated in a fiberglass material rather than suspended as a liquid. The advantage of the permeation design, is that there is no out gassing of hydrogen and oxygen. The disadvantage of AGM Batteries is fewer charging, meaning they don't last as long as flooded batteries. AGM Batteries are one of two types of “Sealed” or Valve-Regulated Lead-Acid (VRLA) batteries. See AGM Battery

Grid Connected:
This is an alternative energy or renewable energy source that is connected to the local electrical utility grid. See Grid Interactive System, Grid Tied.

Grid Interactive System:
This is a two way connection to the utility grid, When the alternative energy or the renewable energy source produces more electricity than that which is needed the excess is fed into the utility grid, when the system doesn’t produce enough electricity to meet demand, electricity is fed back into the system from the utility.
See GRID TIED.

Grid Tied or Grid Tied System:
This is an alternative energy or renewable energy source system that is connected to the local electrical utility through some sort of automated switch gear. See GRID INTERACTIVE SYSTEM, ON GRID.

Ground or Earth Ground:
This is a reference point in which voltages are measured. It is also a return path for current or electrons. When referred to in alternative energy or renewable energy systems the ground is usually the negative post on the battery.

Ground Mount:
A type of solar PV ARRAY MOUNT designed for attachment to relatively level flat ground or a nearly flat rooftop. These differ from a flush mount in that they usually have adjustable legs to raise the rear side of the array to better face the sun.

H

#HEV:
Acronym for Hybrid Vehicle

Head or Head Value or Head Pressure:
In reference to hydropower systems, this is the vertical distance the water falls between the inlet and the turbine. The Head Value is used in conjunction with flow rate to determine the power output potential of a hydro turbine location. Turbines are designed with specific head and flow value operating ranges.

HDR:
Acronym for Hot Dry Rock:
See EGS.

Hertz:
Symbol is Hz.:
Is a unit of measurement of the frequency in the directional change of electrical flow or electron flow in alternating current (AC). It is expressed in cycles per second. In the U.S. electrical power from utilities is standardized at 60 Hertz; in Europe and many other countries the electrical power is standardized 50 Hertz.

High Profile Ground Mount:
This is a PV Array mounting structure designed for multiple rows of PV modules. See also LOW PROFILE.

Hydrometer:
A instrument used to measure the specific gravity of a liquid. In lead acid batteries it is used to measure the specific gravity of the electrolyte solution. This electrolytes specific gravity is a direct correlation to the battery's state of charge.

I

Imp:
Symbol for Current at Maximum Power:
This is the current when maximum power is received from the Solar module at peak performance. See Maximum power current, Current at Maximum Power, SHORT CIRCUIT POWER.

Insolation:
Is the measure of the amount of solar energy on a given surface area for a specified time. It is commonly expressed in units of energy per unit of surface area per unit of time. It can be expressed in many forms like: watt-hours per square meter per day (W-h/(m2-day), kilowatt-hours per day ((kW-h/(m2-day). In photovoltaic applications it can be expressed as kilowatt hours per year per kilowatt peak rating (kWh/kWp/y). Other terms sometimes used: "peak sun hours" or "sun hours". To calculate solar energy available and energy potential, Insolation Data is available in tables based on location and other factors such as: array tilt and/or tracking capacity. See PEAK SUN HOURS.

Inverter:
An electronic device that converts typically low voltage DC to a higher voltage AC current. In alternative energy systems, an inverter may take the battery bank's 12, 24, or 48 Volts DC and convert it to 115 or 230 volts AC for use as conventional household current.
Inverter

J

Junction Box:
Is an electrical box for making electrical wiring connections. They can be metal or plastic, they can be hinged or screw down plate lids, they can be made for indoor or outdoor weather tight or weather proof use.

K

Kilowatt:
Symbol is kW:
A unit of power measure equal to 1,000 Watts. See Watts.

Kilowatt Hour:
Symbol is kWh:
A unit of power measurement equal to 1,000 Watt-hours. Commonly used as the unit for electrical energy consumption billing. See Watt hour.

L

Laminar Air Flow:
Undisturbed air flow or air flow without turbulence.
See TURBULENCE.

Load:
A device that consumes electricity.


Low Profile Ground Mount:
This is a PV Array mounting structure designed for primarily a single row of PV modules. This mounting design is intended reduce visibility of the array or to reduce wind loading. See HIGH PROFILE.

Low Voltage Disconnect:
Acronym is LVD:
Circuitry built into some inverters and charge controllers that prevents batteries from being discharged below a specified voltage level. Discharging batteries below the Critical Low Voltage (CLV) can damage the batteries and/or the load. See CRITICAL LOW VOLTAGE.

M

Maximum Power Current:
Symbol is IMP:
This is the current when maximum power is received from the Solar module at peak performance.

Maximum Power Point:
Acronym is MPP:
The highest power output from a given solar module. This value fluctuates depending on the amount of solar radiation and temperature. Maximum Power Point (MPP) is expressed typically in watts.

Maximum Power Point Tracker:
Acronym is MPPT:
This is an electronic device or charge controller that calculates the voltage at which a solar module is able to produce maximum power.

MC Connector or MC:
MC connectors refer to a specialized electrical connector used for connecting low voltage wiring between solar modules to other solar modules and other equipment. MC is a trademarked brand name Multi-Contact. This is part of their Solarline line of outdoor-rated, weather-tight electrical connector systems designed to interconnect PhotoVoltaic panels or modules. Solarline 1 is a non locking connector and Solarline 2’s are locking connectors. These connectors are designated with (+) or (-), to indicate polarity.

Mod Sine:
See Modified Sine Wave

Modified Sine Wave or Mod Sine:
An AC wave form that is a pulse width modified square wave. It consists of the repetition of 3 very small step positive- off - negative. A Modified sine wave is produced by many types of inverters. See SINE WAVE.

N

National Electrical Code:
Acronym is NEC: Also known as NFPA 70:
A set of rules that sets the minimum safety standard in the United States for design and installation of wiring, cabling, conduit and almost all electrical components and Equipment. The National Electrical Code is updated and published by the National Fire Protection Association (NFPA) and on a yearly basis. This code is adopted by most states and municipalities as part of their building. The National Electrical code itself is not law, however it use as the standard is typically mandated by state law or city ordinances. Section 690 of the National Electrical Code sets the standards for solar photovoltaic systems and installation. See NFPA

NEC:
Acronym for National Electrical Code:
See NATIONAL ELECTRICAL CODE

Negative:
This is the point or terminal from which current or electrons flow. This terminal or wire is usually identified by a (-) negative symbol is usually black in color. It also identifies the polarity of a terminal. Designating or pertaining to electrical polarity or direction of current flow. The negative terminal is the point from which electrons flow during discharge of a battery. The negative terminal is the opposite of the “POSITIVE” terminal.

National Fire Protection Association:
Acronym is NFPA:
This is an organization in the United States that creates and maintains the minimum standards for fire prevention, fire suppression techniques, training, equipment and personal gear. An extension or addition to their fire prevention standards are other life safety codes including building codes and the National Electrical Code (NEC).

NFPA:
Acronym for National Fire protection Association:
See National Fire Protection Association

NFPA 70:
See National Electrical Code

Nominal Voltage:
Acronym is NV:
The standard or designed recommended operating voltage of a system or component.

NV:
Acronym for Nominal Voltage:
See NOMINAL VOLATAGE

O

Off-Grid:
It refers to a location that is not connected to a utility electrical grid. Or it can refer just to an electrical generating system that is not connected to a electrical utility grid. See GRID TIED.

Ohm:
The symbol for an Ohm is the Greek letter “Omega” “Ω”:
This is the unit of measurement for electrical resistance. All electrical wiring or electrical conductors, connections and components have a resistance to the flow of current inherit to them. The amount of this resistance to the flow of current is important in the calculations of the design of a system.

Ohm's Law:
Expresses the correlation between Voltage (V) and Current (I) in an electrical circuit. This law is expressed as a mathematical equation: V = I x R. Where (V) is the potential difference in volts, (I) is the current in amperes and (R) is resistance in ohms. If any two of the three values are known, the third value can be calculated by utilizing the formula.

On-Grid:
Referring to a location or an alternative energy or renewable energy source system connected to utility grid power. See UTILITY GRID, GRID TIED, OFF GRID.

Open Circuit Voltage:
Acronym is OCV or Voc:
This is the Voltage between two terminals when there is no load. When referring to Photovoltaic Panels the “open circuit voltage” is measured when the module is exposed to full direct sunlight and with no load connected. This is the highest voltage rating for a Photovoltaic Panel and is used in calculating system size. A photovoltaic panel with a 12V "nominal voltage" will have a Voc rating of about 20V. When referring to a battery, “open circuit voltage” is measured when there is no load connected to the battery.

P

Parallel:
A parallel connection is made by connecting or daisy chaining the positive of one Solar Photovoltaic Panel or Battery to the positive of the next Solar Photovoltaic Panel or Battery. As the Solar Panels or Batteries are connected in parallel, the amperage of this part of the system becomes the sum of all the components (Solar Photovoltaic Panels or Batteries) connected in parallel. The voltage remains the same.

Peak Power Voltage:
Symbol is Vmp:
The voltage at which a solar photovoltaic panel produces the greatest amount of POWER expressed in WATTS.

Peak Sun Hours or Sun Hours:
An approximate unit of measure of solar radiant energy expressed in hours. It is the number of hours per day that solar energy is equal to 1 KILOWATT of POWER per square meter of surface receiving the sunlight or the amount of energy received from sunlight equal to 1 KILOWATT of POWER for 1 Hour over 1 square meter. Peak Sun Hours are used to compare available solar energy at different locations. See INSOLATION.

PHEV:
Acronym for Plug-In Hybrid Electric Vehicle:
This is a conventional hybrid electric vehicle with a backup internal combustion engine for back up power that can be plugged-in to recharge the batteries.

Photovoltaic:
Acronym is PV:
Derived from photo meaning “light” and voltaic meaning “electricity”. The process of converting light into electricity.

Photovoltaic Cell or PV Cell:
This is the device that converts sunlight into electricity. Some materials have a property that causes them to adsorb photons of light and in the process give off electrons or electricity. Individual cells are connected together to form solar panels or modules, these solar panels are connected together to form solar arrays. These cells are manufactured from a semiconductor like CRYSTALLINE silicon. These cells or wafers are thin slices of highly purified silicon and coated with specific VOLTAGE inducing impurities.

Photovoltaic Effect:
This is the process through which a solar cell converts sunlight into electrical current. is produced by (sun)light's interaction with certain elements and chemicals.

Photovoltaic Module:
Synonymous with PV Panel:
See PV Module

Positive:
This is the point or terminal to which current or electrons flow. This terminal or wire is usually identified by a (+) positive symbol and is usually red in color. It also identifies the polarity of a terminal. Designating or pertaining to electrical polarity or direction of current flow. The positive terminal is the point to which electrons flow during discharge of a battery. The Positive terminal is the opposite of the “NEGATIVE” terminal.

Power or Electrical Power:
This is a term for the rate at which work is done or another way of saying it: the rate at which electricity is converted to another form. It is the product of Voltage and Current, it is measured in Watts. See WATTS, KILOWATTS

Primary Battery:
A type of electrical battery that delivers energy but is not designed to be recharged. Alternative Energy and Renewable Energy systems do not use primary batteries for energy storage because they are not designed to be recharged. See Secondary Battery

PV Array or Photovoltaic Array:
Synonymous with Array. A solar Photovoltaic (PV) array is a collection of one or more solar modules combined to form a single electrical output. Photovoltaic array modules are wired in SERIES and/or PARALLEL to produce a specified total VOLTAGE and AMPERAGE.

PV Array Direct:
This is an application of Solar Power where the electricity generated from the Photovoltaic Panel or Array is connected directly to the device utilizing the electricity, without storage batteries to store the electricity. A common application of this type of Photovoltaic System is utilized by most solar water pumps.

PV Cell or Photovoltaic Cell:
See Photovoltaic Cell

PV Module:
Synonymous with Photovoltaic Module, Photovoltaic Panel, PV Panel:
A term for a set number of Solar Photovoltaic (PV) cells interconnected and enclosed in a weatherproof unit. See also PANEL, ARRAY, PHOTVOLTAIC CELL.

PV Panel:
Synonymous with Photovoltaic Module:
See PV Module.

R

# RCD:
Acronym for Residential Circuit Breaker.
See GFCI

# RCCD:
Acronym for Residential Current Circuit Breaker.
See GFCI

S

SAE Connector:
Acronym for Society of Automotive Engineers Connector:
These connectors are a snug fitting, male/female, two prong type based on an automotive industry standard. See Connector Type.

Sealed Lead Acid Battery:
Acronym is SLA:
This is a lead acid battery that is sealed. The electrolyte cannot be replenished. See FLA or Flooded Lead Acid Battery. One advantage of a sealed lead acid battery is the being sealed it prevents the spillage of the acid electrolyte solution.

Secondary Battery:
A type of electrical battery that delivers energy and is designed to be recharged. Alternative Energy and Renewable Energy systems use secondary batteries for energy storage because they are designed to be recharged.  See Primary Battery

Separator:
Synonymous with Battery Separator:
A divider made of a non-conducting porous material that is placed in between the positive and negative plates in a battery cell, allowing current to flow through it while preventing direct contact between the plates which would create a short circuit.

Series:
A series connection is made by connecting the positive to the negative in a series string which causes an increase in voltage. The increase in voltage is the sum of the output of the PV modules or batteries connected together in series

Series-parallel Connection:
PV modules or batteries are wired together, using a combination of SERIES and PARALLEL connections, in order to achieve a particular output voltage and amperage.

Short Circuit Current:
Symbol is Isc:
The current measured from a PV module which is not connected to a load or any other resistance. The value for a particular Solar Module can be found on the specification plate on its back. Measured in Amps.

Side of Pole Mount:
A type of ARRAY MOUNT for attaching a small number of Solar Panels to a vertical pole using clamps or other hardware.

Sine:
Synonymous with Sine Wave:
See Sine Wave

Sine Wave:
Synonymous with Sine, Sinusoid:
An AC electricity waveform characterized by smooth sinusoidal oscillation between equal positive and negative values. See MODIFIED SINE WAVE. Sine wave current is utilized in most utility grid systems. In the United States frequency of the oscillations is set at a standard 60 hertz. See Hertz.

Sinusoid:
See Sine Wave.

SLA Battery:
Acronym for Sealed Lead Acid Battery:
This is a lead acid battery that is sealed. The electrolyte cannot be replenished. See FLA or flooded Lead acid Battery. One advantage of a sealed lead acid battery is the being sealed it prevents the spillage of the acid electrolyte solution.

Solar Panel:
Synonymous with PV Panel:
See PV Panel

Solar South:
Synonymous with True South:
See True South.

Solar Tracker:
A device or mounting rack with motion hardware that keeps a Solar Photovoltaic Array pointed towards the sun. It automatically tilts and/or pans to follow the daily path of the sun across the sky providing for optimum performance. There are two types of tracking technology: "active", using electric motors or "passive" using gas phase change weight transfer. There are Single Axis Tracking and Two Axis Tracking Units.

Solarline:
Is a trademarked name of a connector that is used by some solar photovoltaic panels.
See Connector Type

Specific Gravity:
The ratio of the density of a solution compared to the density of water. In reference to batteries, it is the density of the electrolyte in the battery. Specific Gravity is measured with a hydrometer. In Batteries the Specific Gravity of the electrolyte isdirectly related to the state of charge of the battery.

State Of Charge:
Acronym SOC or SoC:
Is the level of charge in the battery. With 100% indicating a full charge and 30% indicating that 70% of the battery’s charge has been discharged.

STC:
Acronym for Standard Test Conditions:
The rating a manufacturer puts on a nameplate on a Solar Panel is the power that the panel will produce under perfect conditions or Standard Test Conditions.
See STC Watts, Watts Of Solar

STC Watts:
Acronym for Standard Test Condition Watts:
The is the power rating a manufacturer puts on a nameplate on a Solar Panel, it is the power that the panel will produce under perfect conditions or Standard Test Conditions.
See STC, Watts Of Solar

Stratification:
Synonymous with Battery Stratification:
This is a common cause of battery failure. A condition in lead acid batteries, where the concentration of acid is greater at the bottom, than the concentration at the top. The greater concentration at the bottom can promote sulphation and lead to premature battery failure. This condition is caused by undercharging. Stratification can be prevented by periodically performing an equalization charge. See Sulphation.

Sulphation:
In a lead acid battery, during the discharge cycle, lead sulfate crystals form on both the positive and negative plates. If the battery is allowed to remain in a discharged state for a prolonged period of time, the sulfate crystals continue to grow. This build up of sulphate crystals reduces the effective plate area. This heavy build up of sulphate crystals is difficult to dissolve back into the electrolyte solution with normal charging, but can be somewhat reversed by periodically performing an Equalization Charge on the battery. Sulphation can be prevented or at least slowed by fully recharging the battery immediately following a discharge

Sun Hours:
See PEAK SUN HOURS.

System voltage:
This is the NOMINAL VOLTAGE of a renewable energy system as a whole. System voltage is the same as the of the battery bank voltage.

T

Thin-Film:
A broad term for a type of photovoltaic cell or wafer that is based on non-crystalline technology. The manufacture of these cells may or may not use Silicon as their base. Thin-film modules are can be manufactured utilizing a variety of techniques including printing, spraying, or other processes. They can be flexible and can also be manufactured into irregular surfaces.

Temperature Sensitive Charging:
Acronym is TSC:
Battery Charging voltage based on battery temperature. As the temperature of a battery falls, voltage must be increased to achieve optimum charging and the opposite is true, as battery temperature increase, charging voltage should decrease.


Tilt Angle:
This is the angle that the Solar Panel or Solar Array is tilted upward from the horizon. The angle chosen is the angle that provides for maximum Solar exposure and has many variables, including time of day and the season. Solar Tilt Angle is expressed in degrees (°) between 0 and 90. Optimum performance is achieved when sunlight strikes the Solar Panel or Solar Array perpendicularly. The optimum Solar Tilt Angle is calculated based on the Solar Altitude Angle. When installations permit, the Solar Panels or Solar Array tilt angle can be adjusted seasonally to boost production. See ALTITUDE ANGLE.

Tilt Up Mount:
A type of solar ARRAY MOUNT used to attach Solar Panels or Solar Modules to flat surfaces. Typically a tilt up mount has tilt legs that lift up one end of the modules to give the appropriate Solar Panel or Solar Array TILT ANGLE.

Top of Pole Mount:
A type of Solar Panel or Solar Array mount for attaching a Photovoltaic Array to a vertical pole using clamps and other hardware

Transformer:
An electrical device that either increases voltage or decreases voltage. When voltage is increased, current is decreased proportionally and the opposite is also true, when voltage is decreased, currant is increased. Transformers only work with Alternating Current (AC).

True South:
Synonymous with Solar South:
In the northern hemisphere, true south is a line drawn from the south pole to the sun, when the sun is at its at it daily peak.

TSC:
Acronym for Temperature Sensitive Charging:
Battery Charging voltage based on battery temperature. As the temperature of a battery falls, voltage must be increased to achieve optimum charging and the opposite is true, as battery temperature increase, charging voltage should decrease.

Turbulence:
Turbulence is a disturbance in air flow. Moving air or wind that encounters obstacles, like poles, buildings or trees, is disrupted and becomes turbulent. Wind turbine efficiency decrease if the air flow is turbulent. The performance of the Wind Turbine is inversely proportionate to the turbulence in the air flow. Generally the higher the turbine above surrounding terrain and objects the less turbulence that will be encountered. See LAMINAR AIR FLOW.

U

Utility Grid:
A reference to the local Public Power Supply System or Electrical Utility that supplies electricity to the end user or Consumer. In the United States the grid power to most residential consumers is standardized at 240 VAC at a frequency of 60 Hertz (60Hz). Voltages to commercial consumers can vary.

V

VAC:
Acronym for Volts Alternating Current or Alternating Current:
See Alternating Current

Volt or Voltage:
Symbol is V:
The unit of measure of electrical pressure or electrical force. An analogy would be water pressure or Pounds per square inch (PSI).

Voltage or Volt:
Symbol is V:
See Volt

Voltage Drop:
Is the loss of voltage or electrical pressure between the source and the load. This loss is caused by resistance in the wiring, connections and devices that the electricity passes through. The size and length of the wiring can greatly affect voltage drop. The Natioanl Electrical Code has a set standard (NEC) for the proper wire size to minimize voltage drop, over a given distance. Voltage drop is determined by four factors: wire size (guage), length of the wire, (feet), current (Amps), and voltage (Volts). See VOLTAGE.

Voltage Window:
Grid-tied inverters are rated to accept DC voltages from the DC source within a specified ranges or “window”.

W

Water Analogy:
Since water supply is an easier concept for some to understand it is often used as an analogy or example when explaining basic electrical theory. Water is equated with electricity: Where water flow or volume (gallons per minute) is CURRENT (Amps) and water pressure (Pounds Per Square Inch- psi) is VOLTAGE (Volts).

Watt:
Symbol W:
The unit of measure of electrical power consumption. It is the rate of energy conversion. It is equal one amp of current per second. Watts (power) = Amperes (current) x Volts (voltage) or W = A x V.

Watt Hour:
Symbol Wh:
The unit of measure of electrical power consumption used by utilities.. It is the rate of energy conversion. Watt hours are calculated Watts x Hours = Watt hours. Utilities typically bill for electricity based on kilowatt hours consumed or kWh = 1,000 Wh.

Watts of  Solar:
Synonymous with STC:
The is the power rating a manufacturer puts on a nameplate on a Solar Panel, it is the power that the panel will produce under perfect conditions or Standard Test Conditions.
See STC, Watts Of Solar


Wet Cell Battery or Wet Cell:
A type of battery that uses a liquid electrolyte. The most common type is Flooded Lead Acid Battery. Typically these batteries are less expensive and with proper maintenance these batteries have a longer service life (more charge cycles).

Wire Gauge or AWG:
Wire Guage is based on a set standard for wire and cable diameter measurement. The higher the AWG number, the smaller the wire diameter. This wire gauge standard is based on No. 36 AWG being 0.005 inches in diameter, and No. 0000 (4/0 or four aught) being 0.46 inches in diameter. The ratio of these diameters is 92, and there are 40 gauge sizes from No. 36 to No. 0000 (4/0 or four aught), or 39 steps. In the U.S electrical industry, conductors larger than 4/0 AWG are generally identified by the area in thousands of circular mils.
See AWG.