In the world of stationary batteries, terminology is extensive. There are literally hundreds of terms associated with batteries. It is nearly impossible to know and understand them all. I’ve boiled down the list to what I believe are the 17 most important terms and defined them for you today.

1. Ampere-hour rating: The total capacity of a battery or cell assigned by the manufacturer. It is specific to a constant current discharge, electrolyte temperature, end-of-discharge voltage, and duration.
2. Battery: A combination of two or more cells connected together electrically to produce energy. The required operating voltage and current levels are achieved by connecting the cells either in series or parallel or both.
3. Battery monitoring system: A system installed permanently for measuring, storing, and reporting battery operating parameters.
4. Charge controller: An electrical control device that regulates battery charging by voltage control and/or other means.
5. Conductance: Measured in Siemens or Mhos, it is a measurement of the batteries electronic and ionic components to determine how much energy a cell or battery can supply.
6. Float voltage: The voltage that a battery is maintained at after being fully charged. It works to maintain capacity by compensating for self-discharge.
7. Intercell connector (strap): A low resistance current path, either a bar or cable, used to connect cells in series or parallel.
8. Internal ohmic measurement: A measurement of the electronic and ionic conduction paths within a cell or battery that provides state of health information. Output is expressed in terms of conductance, impedance, resistance, or admittance.
9. Parallel strings: The parallel connection of two or more battery strings to achieve higher currents without using cells with larger ampere-hour ratings.
10. Post: A type of terminal used for connections on a cell or battery.
11. State of charge (SOC): It is the measurement of the stored or remaining capacity in a cell or battery expressed as a percentage of its fully-charged capacity.
12. State of health (SOH): A measurement of the general condition of a cell or battery that helps determine the remaining service life.
13. Temperature compensation:   A correction factor based on the temperature deviation from 25°C/77°F.  Employing this temperature correction factor in the percentage of reference value gives the technician an adjusted reading that eliminates the temperature effect on conductance and prevents improper interpretation of the results.
14. Thermal runaway: A condition that is caused by the battery producing more internal heat than the battery can dissipate. If a cell or battery is left in this condition it can cause catastrophic events.
15. Uninterruptible power supply (UPS): A backup power source that kicks in during any period when the normal power source is lost.
16. Valve-regulated lead-acid (VRLA) cell: A type of lead-acid rechargeable cell that is sealed. The only part that is not sealed is a valve that opens to the atmosphere when the internal pressure in the cell exceeds atmospheric pressure by a pre-selected amount.  Hydrogen and oxygen gas recombination occurs inside the container to produce water that keeps the cells hydrated.
17. Vented lead-acid (VLA) cell: A type of lead-acid cell in which the products of electrolysis and evaporation are allowed to escape to the atmosphere as they are generated. It is not sealed like the VRLA.