Important Battery Terms & Characteristics Explained (with Examples)

The battery has an essential function in our everyday existence. However, many of us don’t understand the basics of battery terms and characteristics. In this blog post, we will discuss the different characteristics of batteries and explain some common battery terminology. We will also provide some tips that will help you in keeping a battery in optimum condition. So, let’s get started!

Fundamental Terminologies

Let us start with some basic terminologies of the battery. Though, there may be a chance that you might know them very well, what would be a better way to revise the terms.


An anode is the negative terminal of a battery. It releases electrons to the load and thus performs reduction. This is the normal case where the battery discharges. If the battery is charging, the anode accepts electrons and acts as a positive terminal.


A cathode is the positive terminal of a battery. It accepts electrons and thus performs oxidation. This is the normal case where the battery discharges. If the battery is charging, the cathode releases electrons to the load and acts as a negative terminal.


Representation of a cell
Representation of a cell

A cell is a single unit that stores electrical energy. It basically has positive and negative terminals and an electrolyte. When it is connected to a circuit, a chemical reaction happens through the terminals and the electrolyte to discharge electrical energy.


Representation of a battery
Representation of a battery

A battery is a group of two or more cells connected in a specific pattern(either series or parallel) that depends on the purpose. Thus the battery is used at larger power requirements.


A battery is connected to an external circuit at its terminals. Every battery has a positive and negative terminal.


An electron is a negatively charged particle in an atom. It revolves around the nucleus of the atom. The electrons are released, acquired, or shared during the chemical reactions.


An electrode is a conductor through which electrons flow in a cell to produce electric energy. Every cell has a positive and negative electrode.


An electrolyte is a solution of chemical compounds that facilitates ions to react with cathode and anode.


Current is the rate of flow of electrons. It is expressed in Ampere(A).

Voltage Drop

A voltage drop is a net difference in potential when measured across two ends of a conductor. It is expressed in volts (V).


It is basically the amount of power released. In the case of a battery, the energy is the amount of electrical energy released. The equation to find the energy of a cell is

E = Voltage x Discharge Rate x Discharge Time

Cell energy is usually expressed in milli-Watt hours (mWhr).

Terms Related to Battery Operation

Now let us discuss some terms related to the operation of a battery. It also includes the terminologies that mention various stages of battery operation.

A representation of Battery Capacity
A representation of battery capacity


A rechargeable battery is technically called an accumulator.

Ambient Temperature

It is the average temperature of the surrounding medium of a battery. In general, higher temperatures tend to accelerate chemical reactions within the battery, which can lead to increased power output. However, if the temperature gets too high, it can cause the battery to overheat and become damaged.

Conversely, low temperatures can slow down chemical reactions and reduce power output. Additionally, extremely cold temperatures can cause the battery fluid to freeze, which can damage the battery cells. As a result, it is important to take ambient temperature into account when operating a battery-powered device.


Battery capacity
Battery capacity

The capacity of a battery refers to the amount of energy that it can store. This is typically measured in terms of the number of hours that the battery can power a particular device, such as a flashlight or a laptop.

The capacity of a battery is affected by a number of factors, including its size, its chemistry, and its design. For example, batteries with a higher capacity will typically be larger in size than those with a lower capacity.

Charge Rate or C-Rate

C-rate of a battery
C-rate of a battery

C-rate is a measure of the rate at which electrical current is drawn from a battery. It is expressed as a multiple of the battery’s capacity, which is the amount of current that can be delivered for one hour.

For example, if a battery has a capacity of 1,000 milliamp-hours (mAh), a C-rate of 0.5 would indicate that the current draw is 500 mA or half the capacity of the battery. A C-rate of 2 would indicate that the current draw is 2,000 mA or double the capacity of the battery.

Constant Current Charge

It is the process of charging where the current is maintained constant throughout regardless of the voltage of a cell. Constant current charging is typically used for fast-charging applications, as it allows for a higher rate of charge than constant voltage charging.

There are several advantages to constant current charging, including improved safety and a lower risk of overcharging. However, it is important to note that constant current charging must be carefully monitored, as it can damage batteries if not done correctly.

Constant Voltage Charge

It is the process of charging where the voltage applied is maintained constant throughout regardless of the current drawn. This technique is often used for lead-acid batteries, as it helps to extend their lifespan by preventing them from being overcharged.

The main disadvantage of constant voltage charging is that it can take longer to charge a battery than other methods, such as constant current charging. However, this method is generally considered to be safer for both batteries and chargers, making it a good choice for many applications.


Battery Terminal Corrosion
Battery Terminal Corrosion

Corrosion is the chemical process that leads to the degradation of battery terminals. Uncontrolled corrosion results in battery failure. To prevent corrosion in batteries, manufacturers use a number of different materials and coatings, such as zinc and chromate.

However, even with these precautions, it is still important to regularly inspect batteries for signs of corrosion and to clean them if necessary.

Cutoff Voltage

Cut-off voltage is the minimum voltage that a battery can be safely discharged to without damaging the battery. Cutoff voltage is also called End-of Discharge voltage. Most batteries have a cut-off voltage of around 2.5 volts per cell, which means that a battery must not be discharged below 2.5 volts multiplied by the number of cells in the battery.

For example, a typical AA battery has three cells, so the cut-off voltage would be 2.5 x 3 = 7.5 volts. Once a battery is discharged below its cut-off voltage, the chemical reaction that generates electricity will stop and the battery will be unable to hold a charge. Therefore, it is important to ensure that batteries are never discharged below their cut-off voltage.

Cycle Life

A battery’s cycle life is the number of times it can be discharged and recharged before it reaches the end of its useful life. For most consumer applications, a battery’s cycle life is typically between 300 and 500 cycles. Lithium-ion batteries, however, can last up to 1,500 cycles. The cycle life of a battery is directly related to its depth of discharge (DoD).

Number of cycles vs Depth of discharge of a battery
Number of cycles vs Depth of discharge of a battery

For example, a battery with a 50% DoD will have twice the cycle life of a battery with a 100% DoD. In general, the shallower the discharge, the longer the cycle life.

Deep Cycle

A battery’s deep cycle refers to its ability to be repeatedly discharged and recharged without damaging the battery. The depth of discharge (DOD) is the measure of how much charge has been used relative to the battery’s full capacity.

For example, if a 100 amp-hour (Ah) battery is discharged by 50 amps, the DOD would be 50%. A battery that can withstand many deep cycles will have a high DOD.


Discharging is the process in which the battery releases its electrical energy to the circuit.

Energy Density

Energy density is the volumetric estimation of energy stored in a battery. It is the ratio of cell energy to its volume. There are several factors that contribute to the energy density of a battery, including the type of electrodes used, the electrolyte used, and the size and shape of the cell.

Internal Resistance

Internal resistance is the resistance offered by the ionic and electronic components of the cell. Internal resistance can be decreased by using higher quality materials in the construction of the battery, and by keeping the battery’s internal components cool.

Limiting Current

The term “limiting current” refers to the maximum amount of current that can be drawn from a battery without damaging it. This limit is set by the battery’s internal resistance, which regulates the flow of current between the battery’s positive and negative terminals.

When the limiting current is exceeded, the battery’s internal resistance increases, causing the battery to overheat and potentially explode.


The chemical reaction that results in the release of electrons is known as oxidation.

Primary Cell

Non-rechargeable cells are called primary cells. The alkaline and zinc-carbon cells are primary cells.


The chemical reaction that acquires electrons is known as reduction.

Secondary Cell

Secondary cells are rechargeable cells. Most devices including mobile phones use secondary cells.

Self Discharge

When batteries are unused for a long period, the amount of energy that a battery can store begins to decline, and eventually, it will no longer be able to power devices. One way to prolong the life of a battery is to keep it stored in a cool, dry place. This will slow down the self-discharge process and allow the battery to be used for a longer period of time.

Another way to reduce self-discharge is to use devices that are designed specifically for low-power applications. These devices draw less current from the battery, which reduces the amount of energy that is lost over time.


The separator is insulation in the cell that keeps the anode and cathode separate.

Service Life

Service life is the useful lifetime of a battery until it hits its cutoff voltage.

Shelf Life

The shelf life of a battery is the maximum duration in which the battery can be stored in the preferable conditions so that it retains its performance when used. Read more

Specific Energy

It is the amount of energy that can be stored in a battery per unit of mass (in units of watt-hours per kilogram, or Wh/kg). The higher the specific energy, the more energy a battery can store for a given mass.

Trickle Charge

Trickle charge is a low-rate charging of a battery with a constant-current supply to maintain the battery in a fully charged condition.

Tips to keep a battery in optimum condition

If you want to keep your battery in optimum condition, there are a few things you can do.

Don’t discharge a battery completely. This can damage the battery and shorten its lifespan.

Avoid overcharging the battery. It can cause the battery’s electrodes to degrade over time, which reduces the capacity of the battery.

Keep the battery clean and free of debris. This will help to prevent the build-up of corrosion and other materials that can damage the battery.

Avoid extreme temperatures. Extreme cold or heat can also damage your battery. When it’s cold, the battery drains faster and doesn’t charge as well. When it’s hot, the battery can overheat and become damaged.

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