All About Battery Energy

Contributing towards global net zero

Glossary of battery related terminology

Here are some battery specifications and their meaning, along with the relevant terminology which is useful to know when comparing batteries for any application:

Table of Contents

Alternating Current (AC)

In an alternating current, the flow of electric charge goes changes direction periodically. Alternating current is the type of current used in most household electrical systems and is typically supplied by power grids.

Battery terminal

The connection point on a battery where electrical current flows in and out of the battery. Each battery typically has two terminals, one positive (+), usually in red colour, and one negative (-) usually in black.

Capacity

The amount of electrical charge a battery can store, usually measured in ampere-hours (Ah) or milliampere-hours (mAh)

Charge

The process of replenishing the stored energy in a battery by applying an external electrical current. Not all batteries are rechargeable, and it is very important to never connect a non-rechargeable battery to a charger, to prevent leakage, rupture, gas generation, overheating (fire hazard) or even an explosion.

Closed Circuit Voltage (CCV)

The voltage of a battery when it is connected to a load or a circuit.

Cold Cranking Amps (CCA)

The Amps an automotive battery can provide to crank (start, rotate) an automotive engine. They are called “Cold” because the Amperage is measured when the battery is cold, meaning not operating for a while, as would be typical in a car that’s parked and we need to start its engine.

Current

The flow of electric charge through a circuit or cable. It is measured in Amperes (A).

Cycle Life

The number of charge-discharge cycles a battery can undergo before its capacity drops to a specified level.

Direct Current (DC)

In a direct current, the flow of electric charge goes runs continuously in one direction through the circuit. Batteries and many electronic devices produce direct current.

Discharge

The process of releasing stored energy from a battery by allowing current to flow from the battery to a connected device or circuit. Also, the process of actively discharging a battery, for example to prevent Memory Effect, to calibrate it, to balance individual cells of Li-ion batteries in a multi-cell lithium-ion battery pack or to prepare a battery for long-term storage.

Inverter

An inverter is an electronic device that converts direct Direct Current (DC) into Alternating Current (AC).

Memory effect

A phenomenon where a battery appears to have reduced capacity due to incomplete discharge and recharge cycles. This effect is more common in older nickel-based rechargeable batteries.

Open Circuit Voltage (OCV)

The voltage of a battery when it is not connected to a load or a circuit.

Rechargeable or Non-rechargeable

The ability of a battery to be recharged using a charger, or not

Self-discharge

The loss of battery capacity over time due to internal chemical reactions, even when the battery is not in use or connected to an appliance or circuit.

Shelf Life

During storage, batteries can undergo self-discharge, which is the gradual loss of capacity over time even when not in use. Factors such as temperature, battery chemistry, and the specific design of the battery can influence the rate of self-discharge. The shelf life specification of a battery states how long a battery can be stored without significant capacity loss or deterioration. This is particularly important for batteries that may be kept in storage for extended periods. The shelf life is typically measured from the date of manufacture.

Temperature Range

The range of temperatures under which a battery can work optimally without losing charge too quickly.

Trickle charger

A trickle charger is a type of battery charger designed to provide a low and constant charging current to a battery over an extended period of time. It is commonly used to maintain the charge of a battery that is not regularly used, such as during long-term storage or for vehicles or equipment with low power demands. Trickle chargers are typically designed to deliver a low charging current, often below 1 ampere, which is significantly lower than the charging rates of standard battery chargers. The purpose of this low current is to provide a slow and steady charge to the battery, compensating for the self-discharge that occurs over time.

Voltage

The electrical potential difference between the positive and negative terminals of a battery, measured in volts (V). All batteries have a voltage rating, and using the correct battery for your application is crucial as a wrong battery can cause serious damage to your appliance.