Ampere: A unit of measurement for electrical current.
Ampere Hour (Ah): The quantity of electrical energy corresponding to the flow of current of one ampere for one hour. This term is used to signify the energy stored in the battery.
Battery Capacity: The total number of ampere hours (Ah) that a fully charged battery can output.
Cycle: One sequence of charge and discharge.
Discharging: When a battery is delivering a current.
Over Charge: The process of continued charge of cell / battery after the point of 100% charge capacity.
Over Discharge: The process of discharging a cell / battery beyond its cut off voltage.
Volt: A unit of measurement of electrical energy within an electrical circuit.
Most Lithium batteries come as 12, 14.4, 18, 20, 24, 36, 48, 52, 58, or 72 volt , with each cell as 3.7 volts.
State of Charge (SOC)(%): An expression of the present battery capacity as a
percentage of maximum capacity. SOC is generally calculated using current integration to
determine the change in battery capacity over time.
Depth of Discharge (DOD) %: This expresses the percentage of battery capacity that has been discharged expressed as a percentage of maximum capacity. A discharge to at least 80 % DOD is referred to as a deep discharge.
BMS: Battery Management System, is an electronic system designed to monitor and manage battery performance, protecting it from damage and optimizing its lifespan.
Cell: A cell is the basic building block of a battery, consisting of an anode, a cathode, and an electrolyte. The voltage of a cell in an 18650 Lithium Ion battery is 3.7 volts, whereas the voltage of a LiFePO4 cell is a nominal 3.2 volts.
Closed Circuit Voltage Test : Closed Circuit Voltage Test is a method for testing battery performance by measuring voltage while the battery is connected to a load and discharging.
Watt Hours: This is usually stated on the battery itself. If not, you can calculate it as Volts x amp hours (Ah).
- example 1: an 18 volt 5000 mAh battery – first divide the mAh rating by 1,000 to get the Ah rating – 5000/1,000 – 5.0ah. You can now calculate as – 5Ah x 18 volts = 90Wh
- example 2: a 36 volt 17.0Ah battery – 17Ah x 36 volts = 612Wh
Memory effect: This commonly associated with Nickel-Cadmium batteries, is a
phenomenon where a battery appears to “remember” previous partial
discharge levels, causing reduced capacity over time.