18650 battery vs AA - key differences you need to know

Choosing between using a 18650 battery vs AA can be challenging as it is one of the most confusing battery topics. Modern devices must draw power from the correct type of battery to function correctly. This article provides a comprehensive and in-depth analysis of the specifications, differences and uses of 18650 battery vs AA, aiming to help you make the most appropriate choice between the two. In addition to the comparison of these two batteries, you may also want to know where to buy 18650 batteries. Our article also mentions a detailed answer to this question, and you'll find advice below.

1.What does 18650 mean on a battery? Why are 18650 batteries so popular?

18650 batteries derive their name from the dimensions of that battery - 18mm x 65mm. In other words, it refers exclusively to the size of the battery. All 18650 batteries are lithium rechargeable batteries. The primary reason why 18650 batteries are so popular is because you can recharge them 4,000 times. In addition, 18650 batteries are reliable and have a wide array of uses, for example, flashlights, some electric vehicles, medical equipment, etc.

2.Everything you need to know about the 18650 battery

① What is the highest capacity 18650 battery?

The highest capacity 18650 battery has 3,600 mAh. Consider the following illustration to help you understand its capacity better: Your 18650 battery with a capacity of 3,600 mAh can deliver a current of 3600 mA (or 3.6 A) for one hour.

② How many times can a 18650 battery be recharged?

You can recharge your 18650 battery up to 4,000 times - If your 18650 battery uses lithium iron phosphate cells, it can be used for 10 years (4000/369 ≈ 10.96) on the premise of charging and discharging once a day on average. If you regularly use your 18650 battery under high-drain applications, the cycle life may reduce. Therefore, if you want to extend the cycle life of the 18650 battery, you need to control the battery cycle times and develop good charging and discharging habits.

③ What devices use 18650 batteries?

One of the reasons why the 18650 battery is popular is because of its wide array of applications. You'll find the 18650 battery widely used in flashlights, laptops, cameras, electric vehicles, power banks, and remote-controlled toys, among others.

④ How do I choose an 18650?

• Battery capacity and discharge current - a higher battery capacity means that your battery can providelonger durations;
• Protection (cut-off technology) - a good 18650 battery should be protected because it can become sensitive to charging, discharging, and environmental temperature conditions. Protected 18650 batteries prevent battery damage by monitoring your battery and shutting it down until better conditions are met;
• While unprotected 18650 batteries offer a slightly higher battery capacity, it would be better if you’d consider getting a protected one;
• Buy your 18650 battery from a reputable battery stores- you may find cheap 18650 batteries with a high capacity sold by sellers who have rewrapped batteries. You cannot verify the authenticity of the information provided on the rewrapped batteries, meaning they may be unsafe for use. The professional and trustworthy lithium batteries store is just the opposite. TYCORUN ENERGY is a battery store specializing in selling the best lithium batteries, and our products have undergone strict testing to ensure product quality;
• Flat top or button top (cathode side) - most devices can use either the flat or button top. However, confirming which type your device handles best would be best.

3.What is an 18650 battery equivalent to? Are 18650 batteries bigger than AA?

The nominal voltage of the 18650 lithium battery is 3.7V, which is equivalent to three nickel-cadmium or nickel-hydrogen batteries connected in series. On the other hand, AA batteries are either 1.2V (rechargeable) or 1.5V (disposable), so to get the same voltage as one 18650, you'd need the equivalent of 2.5 AA batteries connected end to end. Yes, there is a clear distinction between the two batteries by just looking at them. 18650 batteries are bigger than AA batteries. Remember, 18650 batteries have 18mm x 65mm as their standard dimensions. On the other hand, AA batteries have 14.5mm x 50.5mm.

4.A complete guide to AA batteries

① Are 3.7 V batteries the same as AA?

3.7V batteries generally use lithium iron phosphate materials, and are usually rechargeable batteries. Unlike 3.7V rechargeable batteries, AA batteries are divided into two categories: rechargeable and non-rechargeable. Rechargeable AA batteries are usually nickel-metal hydride, nickel-cadmium and lithium-ion batteries, while non-rechargeable AA batteries are usually disposable alkaline zinc-manganese dioxide cells. As mentioned above, the biggest difference between 3.7V batteries and AA batteries is the voltage, 3.7V represents the nominal voltage of lithium iron phosphate batteries, while the voltage of AA rechargeable batteries is 1.2V, and the voltage of non-rechargeable AA batteries is 1.5 V

② What are the different types of AA batteries? Which AA battery is strongest?

There are four main types of AA batteries:

• Lithium-based (rechargeable) (Li-FeS2)
• Zinc Carbon
• Alkaline
• Nickel-based (NiMH, NiZn)

The lithium-ion AA battery stands out when comparing the strengths of different AA batteries. Li-ion AA batteries produce a current between 3,000 mAh and 3,500 mAh, depending on the manufacturer. Other AA battery types, such as zinc-carbon, alkaline, and nickel-based, produce a current of 400 mAh - 1,500 mAh, 2,000 mAh - 3,000 mAh, and 700 mAh - 1,500 mAh, respectively. Consider the following table as a summary of the differences between the four main types of AA batteries:

③ What is the average life of a AA battery?

A typical AA battery should last for 2 to 3 years if handled correctly. Among them, lithium-ion AA batteries are long-lasting with a cycle life of 3 years even more if properly cared for and charged and discharged on time. However, different factors may affect the average life of AA batteries, these factors include battery usage, temperature, charging characteristics, etc.

④ How do you make AA batteries last longer?

Here’s how you can make your AA batteries last longer:

• It would be best to acquire rechargeable batteries instead of non-rechargeable ones. Rechargeable batteries will serve you for longer durations than non-rechargeable ones.
• Using your AA battery for the right job dictates how long your battery will last.
• Do not leave your batteries in unused devices.
• Some AA battery types, such as the NiCD and alkaline, may last longer by being refrigerated when outside temperatures are high. However, you'll have to warm them up first before reusing them.
• Charging - some AA batteries, such as the alkaline and NiMH, require frequent charging to last for long. The good thing is that they do not consume a lot of electricity to recharge.

5.In-detail comparison of 18650 battery vs AA

This section compares the differences and charging characteristics of the 18650 battery vs AA.

① What is the main difference between 18650 battery vs AA?

There are five main differences between the 18650 battery vs AA:

② Can I charge 18650 battery with AA charger?

No, you cannot charge a 18650 battery using an AA charger. Remember, 18650 batteries have a nominal voltage of 3.7V, while AA batteries have 1.5V. An AA charger will not charge anything with a voltage of 2V and above since its cut-off voltage is 2V.

③ Can I replace AA battery with 18650?

No, you cannot replace (or use) an 18650 battery in place of an AA battery. The differences in their capacities and nominal voltages make it challenging to replace them, even if you connect AA batteries in series to increase their voltage. AA batteries have 1.5V x 3 = 4.5V, while a 18650 battery has a nominal voltage of 3.7V. Simply put, replacing your AA battery with a 18650 battery is not recommended.

④ 18650 battery vs AA, which is better?

You'll need to consider their uses when comparing which battery is a better choice, the 18650 battery vs AA. If you wish to power devices such as flashlights, laptops, cameras, etc., a 18650 battery is a better choice. However, if you wish to power high-drain devices such as remotes, thermometers, and battery-powered hand tools, then AA batteries are most suitable.

6.Conclusion

Choosing between using a 18650 battery vs AA can be challenging as it is one of the most confusing battery topics. The primary reason why 18650 batteries are so popular is because you can recharge them up to 4000 times or more with proper use. There are four main types of AA batteries; Li-ion, zinc-carbon, alkaline, and nickel-based. Li-ion AA batteries are the strongest in that category. The highest capacity 18650 battery has 3,600 mAh. A lithium-ion AA battery has a capacity (highest) of 3,500 mAh. When comparing the sizes of the 18650 battery vs AA, the former is a little bit bigger (18mm x 65mm) while the latter is smaller (14.5mm x 50.5mm) - hence the extra capacity.

Experts strongly discourage replacing 18650 batteries in places of AA batteries. The differences in their capacities, as well as their voltages, make it difficult to switch these batteries. Deciding which is better between the 18650 battery and AA depends on where you want to use the battery. 18650 batteries work best in power electronics such as laptops, cameras, flashlights, etc., while AA batteries work best in high-drain applications such as electric tools, thermometers, remotes, etc. Using your batteries according to their intended purpose and charging them correctly will help you have long-lasting batteries - they'll serve you for a long time.

In addition to the comparison with AA batteries, the difference between 18650 batteries and 4680, a relatively advanced large cylindrical battery technology, has also received widespread attention. Our website summarizes the content of 4680 battery vs 18650 for you, so that you can get more comparative analysis of the two generations of cylindrical batteries.

Related article: lithium vs alkaline batteries, what is an 18650 rechargeable battery