AA and 18650 batteries are very similar, so many people wonder what the difference is between them. Should I use 18650 batteries or AA batteries? This to these confusions, this article makes a comprehensive analysis of these two types of batteries, designed to help you make the right choice.
What is an 18650 battery?
The 18650 battery measures approximately 18 x 65 millimeters. It is slightly larger than an AA battery and has a nominal voltage of 3.2 to 3.7 volts and a nominal capacity of 1800 to 3500 mAh. In addition, 18650 batteries vary in the physical shape of the anode; some have a flat top on the cathode side, while others have a button top.
All 18650 batteries are rechargeable lithium batteries and must be used with a BMS to prevent overcharging and over-discharging of the battery. 18650 batteries have no memory and can be recharged and used at any time without a full charge. For this reason, 18650 batteries can be very popular.
In addition, the physical shape of the anode varies in 18650 batteries. Some batteries have flat anode tips, while others have pointed anode tips.
Pros
- High capacity: 18650 batteries usually have large capacity, suitable for high power consumption devices and long time use.
- Long Life: With a long charge/discharge cycle life, they can last for a long time.
- Rechargeable: 18650 batteries are rechargeable and reusable, environmentally friendly and economical.
- No memory effect: Users can charge or partially discharge the battery at any time without having to completely discharge and recharge the battery.
- Low internal resistance: This means that the battery can provide higher current output without overheating or being damaged in high power demand situations. Low internal resistance also contributes to the efficiency of battery charging and discharging.
- Wide range of applications: Widely used in various fields due to its excellent performance.
Cons
- Strict production: The production process of 8650 batteries requires strict control and quality assurance to ensure the performance, safety and stability of the batteries, which may result in higher production costs.
- Fixed size and shape: 18650 cells are fixed in size and shape, which may limit their applicability to certain devices or products, requiring the design of special battery compartments.
What are AA batteries?
AA batteries are smaller than 18650 batteries, measuring only about 14 x 50 millimeters. Standard AA batteries have a nominal voltage of 1.5 volts. Capacities range from 1800 to 2700 mAh.
However, rechargeable and non-rechargeable AA batteries have different chemistries. Rechargeable AA batteries are now available in lithium-ion, nickel-metal-hydride, and nickel-cadmium chemistries. However, the typical AA battery that people talk about is usually non-rechargeable.
Pros
- Portability: AA batteries are compact, easy to carry and store, suitable for many household devices.
- Universality: AA batteries are a common and widely used standard battery, easy to find and replace.
- Low cost: AA batteries are also available in rechargeable versions, which can effectively reduce the overall cost of use.
Cons
- Environmentally friendly: Disposable AA batteries can easily pollute the environment if not disposed of properly.
- Cost-effective: If your device requires frequent battery replacement, it can be inconvenient and the cost of purchasing batteries can increase significantly.
- Limited capacity: For devices with high power consumption, AA batteries may not have enough battery life.
Difference between 18650 and AA batteries
Size
You can tell the difference between the two types of batteries just by looking at them. 18650 batteries and AA batteries have a clear difference in size. 18650 lithium batteries have a diameter of 18mm and a length of 65mm, whereas AA batteries (also known as 14500 batteries) have a diameter of 14mm and a length of 50mm, so 18650 batteries are much larger in size and diameter than AA batteries.
Battery chemistry
An 18650 battery is a specific size of rechargeable lithium-ion battery. It is usually made of lithium iron phosphate or nickel cobalt manganese ternary material. AA batteries can be alkaline, zinc-carbon, nickel-cadmium, nickel-metal-hydride (NiMH), and lithium-ion.
Battery voltage
The voltage of 18650 and AA is different, the nominal voltage of 18650 battery is 3.7V, which is equivalent to three NiCd or NiMH batteries connected in series. AA batteries, on the other hand, have a nominal voltage of 1.2V (rechargeable) or 1.5V (disposable), which are not the same voltage level. So to get the same voltage as one 18650, you would have to connect 2.5 AA batteries head to tail.
Capacity
Currently, 18650 batteries have a capacity of 1800~3500mAh, AA lithium-ion batteries have a capacity of 1700~2700mAh, and AA alkaline batteries have a capacity of 600~2700mAh. Overall, 18650 batteries have a larger capacity, so they can store more power and last longer when fully charged.
Amperage
AA batteries have a maximum current of only a few amps, but many 18650 batteries discharge 8-10 times faster than AA batteries.
Rechargeability
All 18650 batteries are rechargeable. You can recharge and reuse them many times. AA batteries are both non-rechargeable (zinc-manganese), which can only be used once, and rechargeable (nickel-metal hydride, nickel-cadmium), which can be used repeatedly.
The main differences
| Attribute | 18650 battery | AA battery |
| Size | 18mm x 65mm | 14.4mm x 50.5mm |
| Capacity | 2000mAh-3500mAh | 1000mAh-3000mAh |
| Vltage | Can power devices longer than AA batteries | Can power devices in less time than 18650 batteries |
| Application | Widely used in high-power devices and applications requiring high-capacity power, such as electric vehicles, mobile power, laptops. | Widely used in consumer electronics such as remote controls, flashlights, toys, watches, etc. |
Which is better? 18650 or AA battery?
Both 18650 and AA batteries have a wide range of uses in their respective fields. When comparing which is better, 18650 batteries or AA batteries, you need to consider their uses. If you want to power laptops, mobile power, balance bikes, 18650 batteries are the better choice. 18650's high performance highlights its advantages, and the emergence of lithium-ion batteries has led to more and more high-tech industries. However, in small devices such as remote controls and thermometers, AA batteries are perfect for this area of devices that do not require high battery performance.
Are 3.7 V batteries the same as AA?
3.7V batteries are generally made of lithium iron phosphate and are usually rechargeable. Unlike 3.7V rechargeable batteries, AA batteries are divided into two categories: rechargeable and non-rechargeable. Rechargeable AA batteries are usually Ni-MH, Ni-Cd and Li-ion batteries, while non-rechargeable AA batteries are usually disposable alkaline zinc-manganese batteries.
The biggest difference between 3.7V batteries and AA batteries is the voltage, 3.7V represents the nominal voltage of Li-Iron Phosphate batteries, while AA rechargeable batteries have a voltage of 1.2V, while AA non-rechargeable batteries have a voltage of 1.5V.
- Voltage: 3.7V batteries have a higher nominal voltage (3.7V) and are suitable for devices with high energy density and power requirements, while AA batteries have a nominal voltage of 1.5V (alkaline) or 1.2V (NiMH).
- Size: 3.7V batteries are usually larger in size and shape, such as 18650; while AA batteries are a common standard size.
- Chemistry: 3.7V batteries are typically lithium-ion or lithium polymer, while AA batteries are typically alkaline or nickel-metal hydride, with different chemistries and performance.
FAQ
Q: What battery can I use instead of 18650?
A: Both 21700 and 26650 batteries can be alternatives to 18650 batteries with higher capacity and higher energy density. However, when selecting a replacement for 18650 batteries, consider the specific requirements of the equipment, such as capacity, size, voltage and intended use.
Q: Can I charge 18650 batteries with an AA charger?
A: You cannot use an AA charger to charge 18650 batteries. The reason is voltage mismatch.AA battery chargers are designed for 1.5V batteries, while 18650 batteries have a nominal voltage of 1.5V.AA chargers may not be able to provide the proper voltage and current to charge 18650 batteries, which may result in overheating, overcharging, or short-circuiting of the battery. Incorrect charging may damage the battery and shorten its life. It is recommended to use an 18650 charger designed for lithium-ion batteries.
Q: Which is more popular, 18650 batteries or AA batteries?
A: Overall, AA batteries have been around longer than 18650 batteries, but each has its own advantages and applications. 18650 batteries have advantages in terms of high power, long life, and rechargeability and are popular in some specialized fields and high-demand devices, while AA batteries are more common and popular in household and general applications due to their popularity, portability, and suitability for low-power devices. Popularity.
