Battery Terms & Definitions


1. Ampere-Hour/AmpHour (Ah):
One Amp Hour is equal to a current of one ampere flowing for one hour.
A unit-quantity of electricity used as a measure of the amount of electrical charge that may be obtained from a storage battery before it requires recharging.
2. Battery:
A source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices.
When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode.
Cathode = Positive
Anode = Negative
Larger Batteries such as Aegis Batteries, are devices that transform chemical energy into electric energy. These batteries are usually a group of two or more electric cells connected together. Whereas your common “household battery” is just a single cell.
3Battery Charger/Recharger:
A device capable of storing/transferring/supplying energy in a battery by running an electric current through it.
*Please see “Product Categories” for more information regarding our Batteries and their corresponding Chargers.  
4. BMS:
A Battery Management System is any electronic system that manages a rechargeable battery, such as by protecting the battery from operating outside its safe operating area, monitoring its state, calculating secondary data, reporting that data, controlling its environment, authenticating it and/or balancing it.
Additional Terms; BMS Cutoff
5. Charge: The act of charging is to provide electric energy back to the battery for continued use.
6. Current: The current that flows into a capacitor when a voltage is first applied.
7. Cycle:   One sequence of charge and discharge.
8. Cycle Life:
The total number of charge/discharge cycles the cell can sustain before it becomes inoperative.
In practice, end of life is usually considered to be reached when the cell or battery delivers approximately 80% of rated ampere-hour capacity.
9. Discharge:
When the stored electric charge is removed and delivered to an electrical appliance, device, etc.
When the charge moves it is called an electrical current.
*Technically, a battery is always discharging anytime it is not being directly charged.
10. Drain:  Withdrawal of current from a cell.
11. Energy: Output capability; expressed as capacity times voltage, or watt-hours.
12. High Current Discharge:
 Withdrawal of large currents for short intervals of time, usually at a rate that would completely discharge a cell or battery in less than one hour.
13. Internal Resistance: The resistance to the flow of an electric current within the cell or battery.
14. Low Current Discharge: Withdrawal of small currents for long periods of time, usually longer than one hour.
15. Negative Terminal: The terminal of a battery from which electrons flow in the external circuit when the cell discharges.
16. Positive Terminal: The terminal of a battery toward which electrons flow through the external circuit when the cell discharges.
17. Parallel Connection:
The arrangement of cells in a battery made by connecting all positive terminals together and all negative terminals together, the voltage of the group being only that of one cell and the current drain through the battery being divided among the several cells.
*Not Recommended*
18. Short: The current delivered when a cell is short-circuited (i.e., the positive and negative terminals are directly connected with a low-resistance conductor).

Short circuit occurs when the positive and negative terminals come into contact with each other or with a metal object, generating heat. Resulting in current becoming zero.

If the batteries are stacked on top of each other or if the batteries are mixed (resulting in a short circuit), this can lead to heat generation, leakage, bursting and eventually fire.

Please note, it is possible to short circuit Lithium batteries. Therefore, you must avoid causing a short circuit when using Lithium batteries.


19. Terminals: The parts of a battery to which the external electric circuit is connected.
20. Voltage: The rate at which energy, electricity or electromagnetic forces are drawn from a source. The specific amount of electricity available in a circuit is an example of voltage.
 *It is recommended to use a battery with the same voltage as your device.