What are the battery sizes, are all the batteries same？

How do I know what size battery to buy

A battery is a device composed of electrochemical cells with external connections to power up electrical devices. Rechargeable batteries come in different shapes and battery sizes.

Whenever you want to buy a battery for your device, the first thing you consider is the battery sizes and shape of the battery and how it fits into the specific device. The battery capacity comes next, after which you check out the voltage then the price.

Which type of battery is best

Different battery types exist worldwide, but we will be considering the three types available for consumer use. The three primary battery types available for consumer use are “Alkaline Battery”, “NiMH Battery”, and the “Lithium Battery”.

Alkaline batteries are single-use, disposable batteries . Do not recharge after all discharge, otherwise there will be safety hazards. They are the cheapest per-unit-basis, and they are very consistent in terms of performance, but they are difficult to recycle.

NiMH batteries, which mean Nickel Metal Hydride Batteries, are more expensive than alkaline batteries. Still, their performance drops with every discharge of the battery, and they also take a long time to charge.

Lithium Batteries have a high charge density with a high cost per unit and are widely used in many long-life, critical devices and portable consumer electronic devices. A rechargeable battery cell with a very high energy density while being extremely stable. The Li-ion battery is used in many consumer electronics and other devices not limited to saws, cordless drills, and hedge trimmers.

Li-ion batteries are also used as backup power in telecommunications applications. The Li-ion battery sizes can store solar energy, wind energy, electrical energy and is used as portable energy in converters and power banks There are many kinds of common lithium batteries.

A polymer battery is a lithium-ion battery classified by packaging, this battery makes use of a polymer electrolyte instead of a liquid electrolyte and is majorly used where weight is a critical feature, such as in some electric vehicles and radio-controlled aircraft.

•Lithium iron phosphate(LiFePO4)
Lithium iron phosphate battery is a kind of lithium ion battery classified by cathode material

The advantages of the lithium battery include:
•It is rechargeable
•Long lifespan
•Zero memory effect
•They require low maintenance
•They come in a wide variety of shapes
•Very low self-discharge
•It comes with high energy density, which reduces the weight and volume of your batteries.

How do I find the correct battery for my device

To find the correct battery sizes for your device, you start by consulting the instruction manual for the battery sizes it uses. Then you decide if to get a rechargeable battery or the single-use one though the rechargeable is advised because it can be used again and again, making them cost-effective. Then the knowledge of how batteries work and their differences will help you find the correct battery sizes for your device.

Are 18650 and 21700 batteries the same size

The lithium-ion battery cell comes in different physical battery sizes, which includes 21700, 18650, 20700 and others.

The 18650 and 21700 Li-ion batteries are not of the same battery sizes because of their different diameters and lengths. The 18650 battery sizes have a diameter of 18mm and a 65mm length (18mm x 65mm) while the 21700 battery sizes comes with a diameter of 21mm and a length of 70mm (21mm x 70mm).

Why are batteries different sizes

Batteries have different sizes because they are not all meant for one single device, as we have different devices with different uses. The same capacity battery, the smaller the volume, the higher the density

The greater the energy density of a battery, the more electricity can be stored per unit volume, or weight.This means more available energy to run your devices, tools and equipment for a longer period.

Batteries with different cells come with different ranges of Ah or mAh. The 18650 cells range from 1200mAh~3600mAh (1.5Ah to 3.0Ah), and most manufacturers settle for 2500mAh. The capacity of 21700 lithium battery can be more than 35% higher than that of 18650.

18650 vs 21700 vs 4680 the difference between them

The 18650 cell measures 18mm in diameter and 65mm in length. At a nominal voltage of 3.7 volts, each cell can be discharged as low as 2.5 volts and charged as high as 4.2 volts, with each cell capable of storing up to 3000mAh.

The 21700 cell is larger than the 18650 and measures 21mm in diameter and 70mm in length. At a nominal voltage of 3.7 volts, each cell can be discharged as low as 2.5 volts and charged as high as 4.2 volts, with each cell capable of storing up to 4800mAh.

The 4680 is a new generation of Li-ion battery cells, and it comes with a 46mm diameter, a length of 80mm, and each of the cell is rated around 9000mAh. It provides five times more energy storage.

Why do 1.5 volts batteries come in different sizes

Depending on the usage of the device, batteries come in different sizes. The larger the battery sizes, the larger the load it can handle. We have different types of 1.5 volts batteries, and they are labeled with alphabets to reflect their battery sizes and the cells they contain. They are generally cylindrical with one positive end and one negative end.

1.5 volts batteries are available in both alkaline and lithium batteries. Lithium makes the batteries powerful with a long-lasting cell type, and they are commonly used for short term use in high drain equipment, but they can also be used in low drain devices as well.

The 1.5 volt batteries include the following:
•AA Battery sizes
•AAA Battery sizes
•AAAA Battery sizes
•C Battery sizes
•D Battery sizes

They all have their different uses due to their varying battery sizes, with the AA battery sizes being the popular cell type and it can be used in almost anything, and they have extensive usage.
The AAA batteries generate less energy and are used by small devices. The AAAA batteries are very small but effective and are used in hearing aid remote controls and more.

The C batteries are heavy duty and are perfect for places where batteries require frequent use, while the D batteries are used for devices that require an extended period of power time.