Solar School Glossary

A – E

  • Battery capacity = how much energy the battery can store; for lead-acid batteries it’s typically stated in amp-hours (Ah), but for li-ion it’s stated in kilowatt-hours (kWh) 
  • Battery discharge = the usage of the battery’s stored electricity. It is when the battery’s stored value decreases  
  • Cycle life = a round trip of complete battery discharge followed by full recharge 
  • Continuous power rating = the amount of electricity that can be supplied continuously. It’s measured in kW  
  • Current = measure of electrons flowing through a wire at a particular time. Its unit is the ampere or amps (A).
  • Depth of Discharge (DoD) = refers to the battery % being discharged compared to its overall capacity  
  • Electrical arc = happens when electrical current jumps a gap in a circuit or between two electrodes
  • Electrical grid/power grid = an electrical infrastructure designed to transmit electricity from its generation facilities (power plants) to homes and businesses

F – J

  • Grid-tied = your energy is sourced from the local utility company as well as your PV system  

K – O

  • Maximum Power Point (MPP) = the highest point of the current-voltage of a solar energy system
  • Net Metering =  providing the ‘grid’ with surplus energy (what your Solar system provided, but which your household is not consuming)
  • Off-grid = when you’re 100% self-reliant in your energy production; you are not connected to your local utility company 

P – T

  • Peak power rating = is the greatest amount of electricity that can be released for short bursts. It’s measured in kW  
  • Power = Current x Voltage. Power is the instantaneous rate at which that energy is transferred. Its unit is the watt (W).
  • Power Electronics = branch of electrical engineering that deals with the control and conversion of electric power to support a variety of needs
  • PV technology = Photovoltaics = generate power through energy-absorbing devices, transforming energy from sunlight into electrical energy   
    • They’re also often referred to as solar panels, or PV panels 
  • Solar inverter =  converts direct current (DC) from solar panels to alternating current (AC) that can be used for a home’s energy consumption.
  • Surge Power (in inverters) = Maximum power the inverter can supply, usually for a short period of time
  • Time-of-use (TOU) rates = An electricity rate structure charging based on when the energy is used

U – Z

  • Voltage = measure of electrical force between two points. Its unit is the volt (V).
  • Watt-hours = are units of electrical energy equivalent to 1 watt of output per hour
    • 1 watt-hour = 3,600 joules1 kWh (kilowatt-hour) = 3,600,000 joules 
    • A 20W light bulb running for 6 hours uses 120Wh

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