Alternating Current (AC) The flows of electricity that constantly changes direction between positive and negative sides. Almost all power produced by electric utilities in the United States (and used by homes and business) is AC current that shifts direction at a rate of 60 times per second.
Ampere (Amp) The unit of measure that indicates how much electricity flows through a conductor. It’s like using cubic feet per second to measure the flow of water.
Amp-Hour Meter This meter measures the cumulative energy going into or out of a system’s batteries, in order to provide an estimate of the state-of-charge.
Battery Box A battery box may be a safety requirement for wet cell batteries and functions to contain hydrogen gas which is then vented to the outdoors. A battery box also protects the battery from the environment in outdoor remote or industrial applications.
Charge Controller A charge controller is an electronic device which regulates the voltage from the solar panels to the correct voltage for a system’s batteries. A charge controller also lowers the voltage and current as the batteries become full. Systems without batteries do not require a charge controller.
Combiner Box An electrical junction box where small output wires from solar panels are combined into pairs of feeder wires leading to the batteries or power inverter. May include circuit breakers or fuses.
Direct Current (DC) Electricity that flows continuously in one direction. Solar panels produce and batteries store DC electricity. Because most homes and businesses use AC electricity, DC electricity must be transformed to AC electricity via an inverter.
Flooded Batteries Flooded batteries (also called “wet cell” are lead-acid batteries that use distilled water as the electrolyte and the water level must be regularly maintained. Like all batteries, their capacity is measured in amp-hours. Lead acid batteries perform better if protected from extreme cold. Flooded batteries are the most economical battery choice for solar power systems.
Inverter A device that converts direct current (DC) electricity to alternating current (AC) either for stand-alone (off-grid) solar power systems or to supply power to an electricity grid (grid-tied). We sell a variety of inverters depending on the application (off-grid or grid-tied)and size of the system.
Junction Box or “j-box” Some solar panels come with J-boxes, and other have pre-attached leads. J-boxes are handy for smaller systems where panels are often in parallel. Pre-attached leads (also called MC Cables) are best for quickly hooking many panels in series for high-voltage grid-tie systems, or larger off-grid systems.
Load The amount of power your site uses. Load may be expressed in kilowatts (capacity) or kilowatt-hours (energy). A site’s peak kilowatts generally refers to when electric demand requirements are highest.
Mounting Equipment Mounting equipment refers to the various equipment used to fasten solar (PV) modules to a roof, to the ground, or to a pole. The mounting equipment varies depending on the environment (snow load, wind), roofing material (asphalt shingles, metal, etc.), size of the solar panels or array, as well as aesthetics (color, trim). We sell a wide variety of rails, pole mounts, ground mounts and roof racks that we can tailor to your needs.
Net Metering Net Metering refers to the practice of allowing utility customers to interconnect PV (solar PV systems allow utility customers to run their electric meters backwards, offsetting their normal utility bill. Net Metering laws vary by country and by state.
National Electrical Code (NEC) The NEC is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Codes series published by the National Fire Protection Association (NFPA), a private trade association.Despite the use of the term “national”, it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices. In some cases, the NEC is amended, altered and may even be rejected in lieu of regional regulations as voted on by local governing bodies. The 1984 and later editions of the NEC contain Article 690, “Solar Photovoltaic Systems” which provide standards for installing a solar PV system.
Overcurrent Protection Overcurrent protection is required by code in the form of Fuses or circuit breakers.
Rebate In order to encourage the use of solar power, many utilities and local non-profit agencies offer rebates after the installation of a solar electric system. Usually the rebates are simply based on the number of Watts of solar panels installed. Please consult your local Utility Company for details.
Sealed Batteries Sealed batteries are also lead-acid batteries, but they are sealed and do not lose electrolyte (and therefore do not need to be maintained) like flooded batteries. Examples of sealed batteries included Absorbed Glass Mat (AGM) or Gel Cell batteries. While sealed batteries are more expensive and require more careful charging than wet cells, they take no maintenance and store very well.
Solar Cells (or Photovoltaic Cell) (PV) A device that produces an electric reaction to light, thereby producing electricity Solar cells are the electrical building blocks for solar panels. The blue or black squares are silicon cells producing about 0.5 volts of DC electricity each.
Solar Panels Solar panels (also referred to as Solar Modules) are panels made up of solar cells connected in series to produce DC electricity. We sell a wide range of solar panels, including smaller 12V nominal panels that have 36 cells in series to produce around 17V at Standard Test Conditions (STC) under load; larger 60 cell solar panels that produce 20 volts nominal at STC; and even larger 72 cell solar panels that produce 24 volts nominal at STC.
Solar Array A group of connected solar panels typically mounted on a roof, on the ground or on a pole.
Tax Credit Tax credits are one type of incentive to install solar/renewable energy systems that may be available at the local, state and/or federal levels. The Federal Income Tax Credit was extended in December of 2015 for several years and is available for both homes and businesses which install solar power systems. Please consult your tax advisor for more details.
Volt (V) The amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and offices use 120 volts.(volts – watts/amps) (volts = amperes x resistance).
Watts Electric measurement of power at one point in time, as capacity or demand. For example, light bulbs are classified by wattage. (1,000 watts = 1 kilowatt).