AA and AAA battery capacity - what does it depend on? How to choose the highest capacity batteries?

Battery capacity and measurements

The capacity of a battery actually determines the amount of electrical charge that a given cell can provide until it is discharged. This parameter is expressed in mAh, i.e. milliampere-hours. With this unit, you can determine the amount of current that the battery is capable of supplying for a certain period of time. Its value depends on the technology and design of the cell. In the case of AA and AAA batteries, the capacity usually ranges from several hundred to even several thousand mAh. Its value has a direct impact on the operating time of the device. The higher the capacity of the battery, the longer it can power the equipment. However, it is worth remembering that there are also other important parameters. When choosing a battery, you should therefore be guided not only by the capacity itself, but also by its internal resistance or efficiency in terms of power demand. The problem, however, is that these parameters (including capacity) are not given on the batteries themselves. However, you can choose the ones that should have the highest capacity based on the information about the design and technology of the battery.

Cell technology

The capacity of the battery is largely influenced by the type of technology in which it was made. For devices with medium and low energy requirements, alkaline cells are most commonly used. Their capacity is on average 1500-3000 mAh (AA batteries average 2500 mAh), depending on the manufacturer or intended use. Batteries of this type can be stored for a long time. For this reason, they are perfect for devices that do not require frequent replacement of energy sources.

Another solution is lithium batteries. Their capacity is higher, as is their current capacity. As a rule, a lithium AA battery has a capacity of about 3000-3500 mAh. This technology provides high resistance to extreme temperatures and a long service life, which is important for devices that need a stable power supply in harsh environments.

Nickel-metal hydride (NiMH) batteries have a capacity of around 600-2500 mA, depending on the model (lower values for AAA batteries and higher for AA batteries). Their advantage is that they are rechargeable, which is why they are very economical in the long run. In addition, lower capacity also means greater durability of the cell, i.e. the ability to charge more times. Remember that for applications with low power consumption, such as solar lamps, it is better to choose more durable rechargeable batteries with a lower capacity.

Size and materials

The capacity of the battery can also be determined by its physical size. For example, an AA battery is larger than an AAA battery. As a result, it also has a higher capacity because it has more space for the active material. Devices that require longer operating time are therefore usually based on AA batteries, and those with lower needs - AAA.

The materials from which the product is made can also be taken into account in the capacity assessment. Electrodes, electrolyte or separator are important, for example. In the case of lithium cells or NiMH batteries, the materials are usually more energy efficient. Therefore, they can store more energy than alkaline cells. It is worth remembering that the manufacturing solutions used also directly affect the voltage stability.

Choosing the right capacity

Many factors influence the choice of a battery with the right capacity, such as the type of device, energy demand or operating conditions. It is worth remembering that the parameter related to capacity does not always have to be the highest. This is because not all devices require cells with the maximum available capacity. In the case of devices with low power consumption, standard alkaline R6 batteries with a capacity of 1500-2000 mAh will be a sufficient solution. This applies, for example, to watches, remote controls or wireless keyboards and mice. Slightly higher requirements are placed on devices with high power consumption, for which lithium batteries with a capacity of 3000 mAh or higher may be necessary. Their use guarantees the supply of optimal amounts of energy in a short time, which translates into greater stability of the equipment. It is worth choosing lithium batteries, for example in the case of specialized cameras or flashlights.