Glossary

Terminology Abbreviation Definition
Amp-hour Ah The unit of measure to show the current storage capacity of a battery. The number of amps that a battery can deliver in 1 hour of time.
Balancing – Active and Passive The act of bringing the voltage of serially connected cells to within a tolerance of each other. The goal of balancing is to equalize discharging between cells and optimize the life of the group. Methods include “active” and “passive”.
Battery – Cell A chemical system that produces DC voltage
Battery – Module A series parallel arrangement of cells including module level battery management controls
Battery – Pack A series parallel combination of modules including pack level battery management controls
Battery Management System A control system governing the charge, discharge, temperature, current, and voltage of a battery module or pack
Constant Current Charge CC The beginning portion of a battery’s charging profile where the charging current is fixed and the charging voltage is dependent on the battery’s state of charge.
Constant Power Charge Mode A fixed kW power charge level.
Constant Power Discharge Mode A fixed kW power discharge level.
Constant Voltage CV The final portion of a battery’s charging profile where the charging voltage is fixed near the battery’s maximum voltage and the charging current is dependent on the battery’s state of charge.
Current Transformer CT An instrumentation transformer used to scale down a large current on the primary side to a smaller current on the secondary side which is measureable by another device.
C Rate C The charge or discharge rate relative to a full charge or full discharge in 1 Hour. For example if a battery is discharged in 30 minutes the C rate is 2.
Electromagnetic Interference EMI A disturbance that affects an electrical circuit
Flicker Utility industry term describing the very short term effect on power quality caused at the start of a load.
Grid Tie Inverter A grid tie (synchronous) inverter changes DC to AC and either sends energy back to the utility company or for immediate use by the home or business owner.
Grid Synchronization While in island mode with the isolation contactor open, the act of aligning the inverter’s output voltage and frequency (point-to-point) with those of the AC utility prior to closing the contactor
Island Mode System could detect abnormal utility conditions, open contactor, and serve customers in an island. When the utility is restored, will re-synchronize and re-connect.
Load Management The active process of balancing the supply of electricity on the network with the load by adjusting or controlling the load.
Peak Shaving The process of utilizing alternative energy sources to meet customer demand during peak-use periods.
Power Factor PF The ratio of real power over apparent power.
Power Factor Correction The process of supplying reactive power to the load in order to bring the power factor of the circuit closer to 1.0.
Rate Arbitrage The practice of profiting through the volatility of energy market prices, brought on by significant changes in daily supply and demand.
Reactive Power The “phantom power” of reactive loads such as inductors and capacitors measured in Volt-Amps-Reactive (VAR)
Smoothing Process to ensure that rapid changes output energy from solar and wind generation can be effectively managed on a utilities grid
State-of-Charge SOC The amount of energy remaining in a battery relative to a full charge.
Watt-hour Wh A unit of measure for energy, the amount of power that can be delivered in 1 hour of time.s