Battery Guide - Primary and Secondary Batteries

There are two types of batteries that all units fall under: Primary Batteries and Secondary Batteries.

Primary Batteries

Without a need to recharge, Primary Batteries are inherently more reliable as they need less upkeep. For this reason, Primary Batteries are a go to resource for many medical purposes, such as for hearing aids and pacemakers. Due to their higher level of reliability, they are incredibly effective for tactical missions as well. In these instances, personnel will carry a variety of spares to replace discharged batteries. They are also great in devices that have a low power drain such as a TV remote. Their low self-discharge rates ensure a long shelf life. However, they do need to be replaced and disposed of after being fully discharged.

Secondary Batteries

A battery built from secondary cells which can be recharged by reversing the flow of the electrical current. This process restores the battery's active materials through a reversed electrochemical reaction after a full discharge.

With the ability to recharge, Secondary Batteries are great for work tools, household appliances, and personal electronic devices. This allows you to power the same device for far longer. They are also well suited for devices that have higher power drains. The reusable nature of these rechargeable batteries makes them more environmentally friendly and recyclable. However, this is not a recommendation; due to their construction, they cannot be safely disposed of like Primary Batteries. Please consult the manufacturer's guidelines for proper recycling methods. Also, please refer to  this link for recycling information and locations.

General Specs

Primary

Secondary

Additional Terms

Terms (A-B)
Ampere-Hour	A unit of electric charge used to measure a battery's capacity
Ampere‐Hour Capacity	A battery's maximum charge and how long it can last on a singular full charge
Anode	The metal electrode that gives up electrons to the load circuit and dissolves into the electrolyte, only in primary and secondary cells
Aqueous Batteries	Batteries which use a saline solution as an electrolyte for lithium ion transfers
Available Capacity	The maximum capacity of battery that can be used to power your devices, typically expressed in ampere-hours or milliampere-hours
Battery	A device which converts chemical energy into electrical energy through a process of oxidation and reduction
Battery Types	Batteries typically come in two different forms. Primary batteries are made to only allow one continuous or intermittent discharge, meaning it cannot be recharged. Secondary (also known as accumulator) batteries can be recharged through a reversed discharge flow
Battery Capacity	The total amount of electrical charge that a battery can hold (usually measured in ampere-hours, watt hours, or some other comparable unit)
Battery Charger	A device designed to supply a battery with more electrical energy after a discharge
Battery-Charging Rate	The rate at which a battery can be recharged after a discharge
Battery Voltage, Final	The voltage at which a battery is considered fully discharged
Terms (C-D)
Capacity	The total amount of electrical charge that a battery can hold, typically measured in ampere-hours
Cathode	The electrode that oxidizes the anode and absorbs electrons
Cell	The basic building block of a battery, an electrochemical device which can store electricity. It is made from positive and negatively charged plates, a separator, and an electrolyte.
Ci	A battery's capacity rating, the ampere-hours that can be delivered through a constant discharge current from the battery over a set period of time (i represents the number of hours, usually between 1-10 hours or 20 hours)
Charge	The process of converting electrical energy into chemical energy in a dead battery by restoring its active materials through a reversed discharge current, which is then stored for future use
Charging	Supplying a battery with electrical energy to restore the active materials of a battery, which converts the electricity into chemical energy
(State of) Charge	The current charge level in a battery's capacity
Charge Rate	The measurement of the current used to fully recharge a battery based on its capacity. This process is measured as multiples of a battery's rated capacity (Example: C/10 means the charge rate in 10 hours, so for a 500Ah capacity battery, this would mean that C/10 = 500Ah / 10h = 50A)
Constant-Current Charge	A charging process in which the current of a storage battery is maintained at a constant value. For some types of lead-acid batteries this may involve two rates called the starting and finishing rates
Constant-Voltage Charge	A charging process in which the voltage of a storage battery at the terminals of the battery is held at a constant value
Cycle	One full sequence of a battery charging and discharging
Cycle Life	The total number of charge and discharge cycles that a rechargeable battery can perform before becoming fully inoperative. A battery is considered to have reached the end of its Cycle Life when it can no longer charge beyond 80% of its total capacity
Deep Discharge	The total withdrawal of a battery's electrical energy before battery has been fully recharged
Depth of Discharge	The amount of power that can actually be used from a battery's total capacity without shortening its lifespan (Example: A battery with a DoD of 80% can only use 80% of its total capacity without damaging itself)
Discharge	The conversion of a battery's chemical energy into electrical energy
Discharge (High-Rate)	Large electrical current withdrawals from a battery which drain it in a short period of time
Discharge (Low-Rate)	Small electrical current withdrawals from a battery which drain it over a long period of time
Drain	The withdrawal of an electrical current from a battery
Dry Cell	A primary battery which absorbs the electrolytes into a porous material to restrain the flow of energy
Terms (E-F)
Electrochemical Couple	The battery's system of active materials that store chemical enery and generate electrical energy through electrochemical processes
Electrode	An electrical conductor through which an electric current enters or leaves a conducting medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum
Electrolyte	A chemical compound which conducts an electrical current by producing ions when combined with solvents (usually water)
Electropositivity	The degree to which an element within a galvanic cell can give electrons in order to oxidize
End‐of‐Discharge	The voltage of a battery when it is fully discharged
Energy	A battery's ability to power electrical devices (expressed as capacity times voltage, or watt-hours&rpar'
Energy Density	The ratio of a cell's energy to its weight or volume
Float Charging	A style of recharging in a secondary cell where it is connected to and continuously charged from a constant-voltage charger which will keep it in a fully charged state
Terms (G-I)
Galvanic Cell	A combination of electrodes which are separated by an electrolyte that can produce electrical energy through electrochemical reactions
Gassing	When electrodes of a cell begin to produce gas, which most commonly occurs due to self discharge or from electrolysis of water in the elctrolyte during charging
Internal Resistance	Resistance against the flow of electrical currents within the cell or battery
Terms (M-N)
Memory Effect	When a battery is constantly discharged before being fully charged, causing it to progressively lose some of its maximum capacity
Negative Terminal	The terminal of a battery through which releases electrons during the discharge cycle
Nonaqueous Batteries	Cells and batteries that do not use water
Terms (O-P)
Ohm's Law	The formula that describes the amount of current flowing through a circuit (Voltage= Current x Resistance)
Open Circuit	An electrical circuit which is not complete and is disconnected from any charge
Open-Circuit Voltage	The difference in potential between a battery's terminals of a cell when the circuit is open
Oxidation	A chemical reaction which releases electrons by the electrode's active material
Parallel Connection	When the cells in a battery are all connected by their positive terminals together and their negative terminals together, which generates the voltage of one cell, but disperses the drain amongst all of the cells
Polarity	The type of charge (positive or negative) of the battery's terminals at its ends
Positive Terminal	The terminal of a battery which receives electrons during the discharge cycle
Primary Battery	A battery constructed solely from primary cells, one that cannot be recharged (These batteries should be immediately discarded after being fully discharged)
Primary Cell	A cell which produces an electric current through an irreversible electrochemical reaction, a cell which cannot be recharged (These cells should be immediately discarded after being fully discharged)
Terms (R-S)
Rated Capacity	The amount of ampere-hours a cell delivers under specific conditions, usually determined by the manufacturer
Rechargeable	Capable of being charged after fully discharging
Recombination	When the gases in a battery recombine to form water during use
Reduction	The chemical process by which the active material of a battery's electrode accepts electrons
Seal	Part of a galvanic cell that restricts the solvent and electrolytes from escaping the cell while preventing air from entireing the cell
Secondary Battery	A battery built from secondary cells which can be recharged by reversing the flow of the electrical current
Secondary Cell	A cell which can be recharged by reversing the flow of the electrical current to restore the active chemical materials
Self Discharge	Discharge that occurs to a battery while in an open-circuit condition
Separator	The permeable membrane that allows ions to pass through the cell without causing short-circuiting
Series Connection	When cells are arranged to connect their positive terminals to the negative terminals of other batteries to create a cumulative voltage
Shelf Life	The period of time that a dry cell can maintain its original energy content (usually 90%) while in optimal storage temperature (21°C or 69°F) from the date it was manufactured
Short-Circuit	When an abnormal connection between a battery's cathode and anode causes the electric current to become limited by creating an unintended traveling path
Short-Circuit Current	The current that is delivered when a cell short-circuited
Starting-Lighting-Ignition (SLI) Battery	A battery designed to start internal combustion engines, usually used to power vehicles when the engine is shut off (In case of emergencies, this battery can be used to power other items)
Stationary Battery	A secondary battery meant to be used in a fixed location
Storage Battery	Economically rechargeable batteries, synonymous to Secondary Batteries
Storage Cell	Economically rechargeable cells, synonymous to Secondary Cells
Terms (T-W)
Taper Charge	A method of charging in which recharging starts with a high current, but as the battery's charge increases from a low charge level, the charging current will decrease
Terminals	The ends of the battery that the external electric circuit connects to
Thermal Runaway	When a lithium-ion battery destroys itself due to overheating caused by overcharging, excessive discharge, or other dangerous conditions (This condition can produce gas, an explosion, excess heat, smoke, and fire)
Trickle Charging	Charging a battery at the same rate as its self-discharge rate
Vent	A mechanism of some batteries that allows gas to escape the cell in a controlled manner to preserve its health
Voltage, Cutoff	A batteries voltage level at the end of a discharge
Voltage, End-Point	A cell's voltage level in which the connected equipment will no longer function and should no longer be used until the cell is recharged
Voltage, Nominal	The voltage of a fully charged cell while it delivers a rated current
Wet Cell	A cell that uses liquid for the electrolyte to flow freely through