Solar energy comes with its own technical language. Whether you are comparing solar inverters, photovoltaic (PV) systems, LiFePO4 batteries or complete energy storage systems, understanding the terminology can make it easier to compare products and identify suitable equipment for a project.
This solar energy glossary explains common terms used in solar PV, battery storage, inverters and renewable energy systems. It covers everything from AC, DC, kW and kWh to MPPT, BMS, hybrid inverters, microinverters and battery energy storage systems.
Solar & Photovoltaic (PV) Terms
Solar Energy
Solar energy is energy obtained from sunlight. Photovoltaic solar panels convert sunlight directly into electricity, while solar thermal systems use solar energy to produce heat.
Photovoltaic (PV)
Photovoltaic, usually abbreviated to PV, describes the conversion of light into electricity using semiconductor materials. Solar PV cells generate direct current (DC) electricity when exposed to sunlight.
Solar Cell
A solar cell, or photovoltaic cell, is the basic electricity-producing component of a solar panel. Multiple solar cells are electrically connected to create a solar module.
Solar Module
A solar module is a group of interconnected photovoltaic cells enclosed and protected from the environment. The terms solar module and solar panel are often used interchangeably.
Solar Panel
A solar panel is a photovoltaic module designed to capture sunlight and generate DC electricity. Solar panels can be connected together to provide the required voltage and power for a PV system.
Solar Array
A solar array is a group of solar panels or modules connected together as part of a photovoltaic system. Arrays can range from a few panels on a home to thousands of modules in a utility-scale solar installation.
Solar Panel Efficiency
Solar panel efficiency describes the percentage of incoming solar energy that a photovoltaic module converts into electrical energy. Higher-efficiency panels can generate more power from a given surface area under equivalent conditions.
Solar Irradiance
Solar irradiance is the amount of solar power reaching a surface per unit area and is normally expressed in watts per square metre (W/m²). Irradiance varies according to factors including location, weather, time of day and panel orientation.
Monocrystalline Solar Cell
A monocrystalline solar cell is manufactured from single-crystal silicon. Monocrystalline technology is widely used in modern photovoltaic modules.
Polycrystalline Solar Cell
A polycrystalline, or multicrystalline, solar cell is made from silicon containing multiple crystal structures. It is an established photovoltaic technology, although monocrystalline modules are now common in many new installations.
Thin-Film Solar
Thin-film solar technology uses thin layers of photovoltaic material deposited onto a supporting surface. Depending on the technology and application, thin-film modules can offer advantages such as low weight or flexibility.
Solar Thermal
Solar thermal technology uses energy from sunlight to produce heat rather than electricity. A common application is solar water heating. It should not be confused with photovoltaic solar panels, which generate electricity.
Concentrated Solar Power (CSP)
Concentrated solar power uses mirrors or lenses to concentrate sunlight and generate heat, which can then be used to produce electricity. CSP is different from conventional photovoltaic solar generation.
Solar Inverter Terms
Solar Inverter
A solar inverter converts direct current (DC) electricity into alternating current (AC) electricity. In a photovoltaic system, this allows electricity generated by solar panels to be used by compatible AC loads or supplied to an electrical grid where permitted.
Hybrid Solar Inverter
A hybrid solar inverter combines solar PV conversion with battery energy storage functionality. Depending on the model and system design, a hybrid inverter can manage energy from solar panels, batteries, the electrical grid and connected loads. Explore hybrid solar inverters.
On-Grid Solar Inverter
An on-grid solar inverter, also called a grid-tied or grid-connected inverter, is designed to operate with an electrical grid. It converts DC electricity from a solar array into AC electricity synchronised with the grid. Explore on-grid solar inverters.
Off-Grid Solar Inverter
An off-grid solar inverter is designed for systems that operate independently of a utility electricity grid. Off-grid systems commonly combine solar panels, battery storage and an inverter, and may also use a generator or another supplementary energy source.
Microinverter
A microinverter is a compact inverter typically connected to one solar module or a small number of modules. Instead of converting the output of a large solar array through one central inverter, microinverters perform DC-to-AC conversion close to the individual panels.
String Inverter
A string inverter receives DC electricity from one or more strings of solar panels connected in series. String inverters are widely used in residential and commercial photovoltaic installations.
Single-Phase Inverter
A single-phase inverter supplies single-phase AC electricity and is commonly used in residential and smaller commercial applications where the electrical installation uses a single-phase supply.
Three-Phase Inverter
A three-phase inverter supplies three-phase AC electricity. Three-phase solar inverters are commonly used in larger residential, commercial and industrial PV systems where a three-phase electrical supply is available.
High-Voltage Hybrid Inverter
A high-voltage hybrid inverter is designed to operate with a compatible high-voltage battery system. Battery voltage ranges vary significantly between manufacturers and models, so inverter and battery compatibility must always be checked.
MPPT – Maximum Power Point Tracking
MPPT stands for Maximum Power Point Tracking. It is a control technology used by solar inverters and charge controllers to obtain suitable power output from a photovoltaic array as operating conditions change.
MPPT Voltage Range
The MPPT voltage range is the DC voltage range within which an inverter's MPPT system is designed to operate. A solar array must be designed so that its operating voltage is compatible with the inverter's specified input and MPPT limits.
PV String
A PV string is a group of solar modules electrically connected in series. Multiple strings may be connected to an inverter depending on its input configuration and MPPT design.
Inverter Efficiency
Inverter efficiency describes how effectively an inverter converts electrical energy from one form to another. Some energy is lost during conversion, so inverter output energy will be slightly lower than the energy entering the conversion stage.
Battery & Energy Storage Terms
Solar Battery
A solar battery stores electrical energy so that it can be used later. In a solar energy system, batteries can store surplus PV generation for use when solar production is lower or when stored energy is otherwise required.
Energy Storage System (ESS)
An Energy Storage System (ESS) stores energy for later use. A solar ESS may include batteries, a battery management system, an inverter or power conversion equipment, monitoring and other control components.
Battery Energy Storage System (BESS)
BESS stands for Battery Energy Storage System. It refers to an energy storage system in which rechargeable batteries are the principal storage technology. BESS installations range from residential battery systems to large commercial and utility-scale projects.
LiFePO4 Battery (LFP Battery)
LiFePO4 stands for lithium iron phosphate and is often abbreviated to LFP. It is a lithium-ion battery chemistry widely used in stationary energy storage applications.
Lithium-Ion Battery
Lithium-ion is a broad family of rechargeable battery technologies. Different lithium-ion chemistries have different electrical, thermal and performance characteristics; LiFePO4 is one example.
Battery Management System (BMS)
A Battery Management System (BMS) monitors and manages a rechargeable battery or battery pack. Depending on the system, it may monitor parameters such as cell voltage, current and temperature and provide protective and communication functions.
Battery Capacity
Battery capacity describes how much electrical charge or energy a battery can store. Energy storage products are commonly specified in kilowatt-hours (kWh), while ampere-hours (Ah) may also be used alongside the battery's nominal voltage.
State of Charge (SoC)
State of Charge (SoC) indicates the approximate amount of energy remaining in a battery relative to its usable or specified capacity. It is commonly displayed as a percentage.
Depth of Discharge (DoD)
Depth of Discharge (DoD) describes how much of a battery's capacity has been discharged relative to a defined capacity. For example, a greater depth of discharge means that more stored energy has been removed from the battery.
Battery Cycle
A battery cycle represents charging and discharging equivalent to a defined amount of the battery's capacity. Partial charge and discharge events can accumulate towards a full equivalent cycle.
Cycle Life
Cycle life is a measure of how many charge/discharge cycles a battery is designed or tested to complete under specified conditions before reaching a defined performance threshold. Actual battery life depends on operating conditions and how the battery is used.
Low-Voltage Battery
A low-voltage energy storage battery operates within a comparatively low DC voltage range. The exact definition and operating range depend on the equipment manufacturer and system architecture.
High-Voltage Battery
A high-voltage battery system uses battery modules configured to operate at a higher DC voltage. High-voltage batteries must be paired with compatible inverters, control equipment and system components.
Battery Module
A battery module is a unit containing multiple battery cells assembled into a larger energy storage component. Several modules may be combined to increase the voltage or storage capacity of a battery system.
Battery Rack
A battery rack is a structure used to house and organise battery modules. Rack-mounted battery systems are common in residential, commercial and larger energy storage installations.
All-in-One Energy Storage System
An all-in-one energy storage system integrates several major components of a battery storage installation into one product or coordinated enclosure. Depending on the design, this can include battery storage, an inverter, battery management, monitoring and energy control functions.
Electrical & Power Terms
Alternating Current (AC)
Alternating current (AC) is electrical current in which the direction of current flow periodically reverses. Electrical grids and many household and commercial electrical systems use AC power.
Direct Current (DC)
Direct current (DC) is electrical current that flows in one direction. Solar PV modules and batteries operate with DC electricity, while an inverter can convert DC into AC.
Watt (W)
A watt is a unit of power. It describes the rate at which electrical energy is being generated, transferred or consumed.
Kilowatt (kW)
A kilowatt is a unit of power equal to 1,000 watts. Solar inverters and photovoltaic systems are commonly described using kilowatts to indicate their power rating.
Kilowatt-Hour (kWh)
A kilowatt-hour is a unit of energy. One kilowatt-hour is the amount of energy used or generated when a power level of 1 kilowatt is maintained for one hour.
kW vs kWh
kW measures power, while kWh measures energy. For example, an inverter may have a 5kW power rating, while a battery may provide 10kWh of energy storage capacity. The two measurements describe different characteristics and should not be used interchangeably.
Volt (V)
The volt is the SI-derived unit used to measure electrical potential difference, commonly referred to as voltage. Solar panels, batteries and inverters all have specified operating voltage ranges.
Ampere (A)
The ampere, commonly shortened to amp, is the unit used to measure electric current. Inverter, battery and PV input specifications commonly state maximum allowable current in amperes.
Rated Power
Rated power is the power level assigned to equipment under specified operating or test conditions. The precise meaning depends on the product and the manufacturer's technical specification.
Peak Power
Peak power generally refers to a higher power level that equipment can provide or withstand for a limited period under specified conditions. For inverters and energy storage systems, peak or surge capability can be relevant when supplying loads with high starting power requirements.
Load
An electrical load is any device, appliance or system that consumes electrical power. In a solar and battery installation, loads can be supplied from solar generation, battery storage, the grid or another source depending on the system configuration.
IP Rating
An IP rating, or Ingress Protection rating, indicates a product enclosure's specified level of protection against the ingress of solid objects and water. Always check the manufacturer's installation requirements even when equipment has an IP rating suitable for particular environments.
Solar System & Grid Terms
Electrical Grid
The electrical grid is the interconnected infrastructure used to generate, transmit and distribute electricity from power sources to consumers.
Grid-Tied / Grid-Connected
A grid-tied or grid-connected solar system operates while connected to an electrical utility grid. The exact rules for connection, energy export and metering vary by country, network operator and local regulations.
Off-Grid
An off-grid energy system operates independently of a utility electricity grid. Solar panels, battery storage and an off-grid inverter are commonly combined to provide electricity, sometimes with a generator or another supplementary power source.
Backup Power
Backup power is electricity supplied when the normal power source is unavailable. Hybrid inverter and battery systems may provide backup functionality, although the available power, transfer behaviour and supported loads depend on the equipment and system design.
UPS / EPS
UPS means Uninterruptible Power Supply, while EPS is commonly used for Emergency Power Supply. In solar and energy storage equipment, these terms may describe backup outputs or functions intended to maintain power to selected loads during a grid interruption. Exact functionality and switching times vary by product.
Self-Consumption
Solar self-consumption means using electricity generated by a solar PV system at the site where it is produced rather than exporting that electricity to the grid. Battery storage can increase self-consumption by storing surplus solar energy for later use.
Energy Export / Feed-In
Energy export occurs when electricity generated by a solar or energy storage system is supplied to the electrical grid. Whether export is permitted and how exported electricity is measured or compensated depends on local regulations and electricity arrangements.
Net Metering
Net metering is an electricity billing or accounting arrangement available in some markets in which exported electricity is credited against electricity drawn from the grid. Rules, eligibility and compensation differ significantly between countries and electricity providers.
Peak Shaving
Peak shaving is the reduction of electricity demand from the grid during periods of high consumption. Battery energy storage can be configured in some systems to supply part of the load during demand peaks.
Energy Management System (EMS)
An Energy Management System (EMS) monitors and controls energy flows within an installation. Depending on the system, an EMS can coordinate solar generation, batteries, loads, grid interaction and other energy sources.
Solar Monitoring
Solar monitoring systems collect and display operating information from solar and energy storage equipment. Depending on the product, monitoring may provide information such as PV generation, battery state of charge, energy consumption, grid import/export and system status.
CAN Communication
CAN (Controller Area Network) is a communication technology used by some batteries, inverters and energy management systems to exchange operating and control information. Compatible communication protocols are important when pairing batteries with inverters.
RS485
RS485 is a serial communication standard commonly used in solar inverters, battery systems, meters and monitoring equipment. The presence of an RS485 interface does not by itself guarantee compatibility between different products; supported protocols must also match.
Solar Installation Terms
Roof-Mounted Solar
A roof-mounted solar system uses mounting equipment to secure photovoltaic modules to a building's roof. System design must take into account factors including roof construction, orientation, shading, loading and local installation requirements.
Ground-Mounted Solar
A ground-mounted solar system installs photovoltaic modules on a supporting structure located on the ground rather than on a building. Ground-mounted systems can range from small private installations to large solar farms.
Solar Farm
A solar farm is a large-scale photovoltaic installation containing many solar panels or arrays, generally designed to generate electricity at commercial or utility scale.
Solar Carport
A solar carport is a structure that supports photovoltaic panels above a parking area, combining electricity generation with a covered or partially shaded parking space.
Solar Canopy
A solar canopy is an elevated structure supporting photovoltaic modules while leaving the area underneath available for another purpose, such as parking, walkways or outdoor facilities.
Balance of System (BOS)
Balance of System (BOS) refers to the components of a photovoltaic installation other than the solar modules themselves. Depending on the system, this may include inverters, cables, mounting equipment, protection devices, monitoring equipment and other electrical components.
Operations & Maintenance (O&M)
Operations and Maintenance (O&M) covers the activities required to operate and maintain a solar or energy storage installation. This can include inspection, monitoring, cleaning, testing, repairs and component replacement.
Balcony Solar & Portable Energy Terms
Balcony Solar System
A balcony solar system is a compact photovoltaic system designed for locations such as balconies, terraces and small residential spaces. Systems commonly combine one or more solar panels with a microinverter, while some configurations also incorporate battery storage.
Plug-and-Play Solar
Plug-and-play solar is a term commonly used for compact solar systems designed to simplify installation and connection. Electrical connection requirements and permitted configurations vary by country, so local regulations and installation requirements must always be followed.
Balcony Solar Storage
Balcony solar storage adds battery energy storage to a compact or balcony photovoltaic installation. Stored solar energy can then be used later rather than necessarily being consumed at the moment it is generated.
Portable Power Station
A portable power station is a rechargeable energy storage device that normally combines a battery, inverter, charging electronics and multiple power outputs in a portable enclosure. Depending on the model, charging sources may include mains electricity, solar panels or vehicle power.
Portable Solar Generator
The term portable solar generator is commonly used for a portable power station combined with, or capable of being charged by, solar panels. Unlike a fuel-powered generator, the power station stores electrical energy in a rechargeable battery rather than generating electricity through combustion.
Renewable Energy Terms
Renewable Energy
Renewable energy comes from sources that are naturally replenished, including sunlight, wind, flowing water, geothermal energy and certain forms of biomass. Solar photovoltaic generation is one form of renewable energy technology.
Zero Net Energy / Net Zero Energy Building
A zero net energy building is generally designed so that its energy consumption over a defined period is balanced by an equivalent amount of renewable energy generation. Definitions and calculation methods can vary between standards and jurisdictions.
Understanding Solar Equipment Specifications
Solar and energy storage products can have similar names while differing significantly in voltage, power, battery compatibility, communication protocols, grid requirements and operating characteristics. Product specifications should therefore be checked as a complete system rather than comparing a single figure such as kW or kWh.
When selecting an inverter or battery, important considerations can include PV input voltage and current, MPPT range, AC output, battery voltage, charge and discharge limits, communication compatibility, backup requirements and the electrical standards applicable to the installation location.
Please contact Keruo Energy for current product availability, technical information and assistance sourcing solar inverters, battery energy storage systems and related solar energy equipment.