AAA Battery Equivalents and Replacements

AAA batteries are very popular household and industrial batteries, being used for powering smaller devices like remote controls, flashlights, toys, calculators, security systems, medical systems, etc.

AAA batteries are available at stores and online shops and getting new ones should NOT be a problem. However, before getting new ones, it is recommended to read a thing or two about their types, chemistries, and other important details.

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AAA Batteries - Features and Specifications

AAA batteries are cylindrical batteries with physical dimensions of (D x H) 10.5 × 44.5 mm (0.413 × 1.752 inches).

AAA batteries were introduced prior to the First World War and are commonly known as 'AAA' batteries, although other names are in use, too, including AAA, MN2400, MX2400, Micro, LR03, R03, Triple-A, etc.

The nominal voltage of AAA batteries is 1.5 volts, although the actual voltage strongly depends on the battery chemistry. The following comparison chart lists some of the most popular AAA battery chemistries in use today:

Chemistry Common Name Rechargeable Typical Capacity (mAh) Nominal Voltage
Zinc Carbon R03, 24D No 500-600 1.5 V
Alkaline LR03, 24A No (Mostly) 850-1200 1.5 V
Li-FeS2 FR03, 24LF No 1100-1300 1.5 V (1.8 V max)
Li-ion 10440 Yes 350-600 3.6 - 3.7 V
Lithium - Yes 400-600 1.5 V
NiCd KR03, 24K Yes 300-500 1.2 V
NiMH HR03, 24H Yes 600-1300 1.2 V
NiOOH ZR03 No 1000-1200 1.5 V (1.7 V max)

Non-rechargeable Zinc Carbon AAA batteries are a cheap source of power for toys and low-end devices. They are reliable but have relatively low capacity and these days they are not as used as before.

Most popular non-rechargeable AAA batteries are alkaline batteries, featuring good capacity, they tolerate relatively high discharge currents and they come at an acceptable price. Also, their shelf life is up to 5-10 years, making them suitable for low- to medium-drain EDC (Every Day Carry) and standby devices.

Non-rechargeable lithium AAA batteries feature shelf life up to 20(!) years and are used even in high-drain devices. The price of these batteries is getting lower and lower as the technology is being improved.

Nickel Cadmium (NiCd) AAA rechargeable batteries were very popular before Nickel Metal Hydride (NiMH) batteries were improved. NiCd batteries can provide large drain currents easily, can be recharged a few hundred times, but they have a strong memory effect, lower capacity, higher self-discharge rate and they contain cadmium, a heavy metal that is a very dangerous pollutant.

Nickel Metal Hydride (NiMH) batteries are very popular rechargeable AAA batteries, featuring nominal voltage of 1.2 volts and capacity in the 600-1300 mAh range - capacity directly depends on the battery design (high discharge rate/lower capacity, or low discharge rate/high capacity, with many models fitting in-between these 'extremes'.

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1.2 volts NiCd and NiMH batteries may replace 1.5 volts batteries in many devices, but just in case, check the Owner's Manual of the device - some units don't operate properly due to the somewhat lower voltage, although this is rare.

NiMH batteries feature much improved self-discharge rate (sometimes even less than 10% annually), practically no memory effect, improved capacity, lower internal resistance (higher discharge currents), etc. As such, rechargeable NiMH AAA batteries are commonly used in various devices ranging from flashlights, cordless tools, home appliances, photo equipment, and similar.

AAA Battery vs 10440 Battery

Rechargeable lithium-ion AAA batteries are also known as 10440 batteries due to the similarities in physical dimensions - 10.5 x 44.5 mm (AAA battery) vs 10 x 44 mm (10440 battery).

The nominal voltage depends on the actual lithium-ion chemistry, but ranges from 3.2 to 3.7 voltage. Capacity depends on the chemistry, but also battery design - low-discharge design (higher capacity) or high-discharge design (lower capacity).

Labels of lithium-ion AAA batteries often include abbreviations like IMR, INR, IFR, or ICR, which describe actual battery chemistry:

- IMR AAA batteries feature LiMn204 (Lithium Manganese Oxide) chemistry, with the nominal voltage of 3.6 - 3.7 V per cell, and the maximum recommended charging voltage of 4.2 V. IMR batteries commonly have a relatively smaller capacity, but are capable of delivering large currents.

- INR AAA batteries feature LiNiMnCoO2 (Lithium Manganese Nickel) chemistry, with the nominal voltage of 3.6 - 3.7 V per cell, and the maximum recommended charging voltage of 4.2 V. These batteries are very similar to IMR batteries - they can also deliver large currents, but with slightly lower capacity.

- IFR AAA batteries feature LiFePO4 (Lithium Iron Phosphate) chemistry, with the nominal voltage of 3.2 - 3.3 V per cell, and the maximum recommended charging voltage of 3.5 - 3.6 V. IFR batteries are one of the safest lithium-ion chemistries, often used in electric bikes/scooters and similar vehicles and power tools without protective electronics, despite having somewhat lower voltage and capacity.

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- ICR AAA batteries feature LiCoO2 (Lithium Cobalt Oxide) chemistry, with the nominal voltage of 3.6 - 3.7 V per cell, and the maximum recommended charging voltage of 4.2 V. ICR batteries commonly have a high capacity, but maximum allowed currents are often limited to just a few C.

Note: there are other lithium-ion battery chemistries on the market too, including hybrid technologies like Lithium Nickel Cobalt Oxide (LiNiCoO2), Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2), etc. These lithium-ion chemistries are commonly used in high-end cordless tools and devices, including some Power Stations.

Lithium-ion batteries may be recharged several thousand times, but must be recharged with the battery chargers intended for such batteries, or they can overheat, catch fire or even explode.

In order to avoid such issues, most lithium-ion batteries come with protective electronics also known as Battery Management System (BMS).

Note: 1.5 volts AAA batteries and 3.2-3.7 volts 10440 are NOT interchangeable types of batteries, due to the large voltage difference. Some devices support the use of both battery types, but this MUST be explicitly expressed by the manufacturer of such device. Or the device can end up in smoke, or even fire, with the warranty void due to the use of unsupported battery type.

AAA Battery Chargers

AAA battery chargers are designed to charge AAA and similarly sized cylindrical batteries.

Most modern battery chargers are intelligent battery chargers that are able to distinguish the battery chemistry and charge the battery according to its chemistry and condition, prolonging the operating life of the battery.

Also, to reduce thermal stress, some battery chargers feature small air fans, keeping the batteries cool.

When choosing the battery charger for your AAA battery, it is often the best to buy batteries and charger combo from the same manufacturer - it is very cost-effective solution, especially for people not already having battery chargers.

18650 Battery vs AAA Battery

18650 battery is a rechargeable, cylindrical, lithium-ion battery featuring physical dimensions of (DxH) 18.6 x 65.2 mm.

18650 lithium-ion batteries are available in the same chemistries just as lithium-ion 10440 batteries - IMR, INR, IFR, ICR and comes with similar features, except larger capacity and larger drain currents.

18650 battery

Some devices that are being powered by 18650 batteries allow the use of three AAA batteries using a special battery adapter. Such practice ensures that the users are able to find the batteries for their devices more easily.

Note: 18650 batteries feature nominal voltage between 3.2 and 3.7 volts, while three AAA NiCd/NiMH rechargeable batteries feature a nominal voltage of 3.6 volts (3 x 1.2 volts), allowing the three AAA NiCd/NiMH to directly replace one 18650 battery. However, three non-rechargeable AAA batteries feature nominal voltage of 4.5 volts (3 x 1.5 volts) and three rechargeable 10440 batteries feature nominal voltage of up to 11.1 volts (3 x 3.7 volts) - read carefully if the single 18650 battery may be replaced with three 1.5V AAA batteries (very often 'Yes') and with three 3.7V 10440 battery (very often 'No').

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Rule of Thumb: If your device support both 18650 and three AAA batteries, use 18650 battery if the device is intended for everyday use and use three high-quality alkaline or lithium 1.5V batteries if the device is intended as EDC or standby device.

Long Story Short: If You are looking for a new non-rechargeable AAA batteries, go for high-quality alkaline or even lithium 1.5 volts batteries. They feature long shelf life and are able to provide energy years, even decades (lithium chemistry) after being manufactured.

If You need rechargeable AAA batteries, NiMH AAA batteries are the way to go - they are relatively cheap, easy to charge numerous times, they hold their charge well, etc, and are suitable for devices that are used often, saving time and money.

10440 are lithium-ion rechargeable batteries with nominal voltage of 3.2-3.7 volts and should be used only if recommended by the device manufacturer.