Is 18650 Battery Same as AA? A Detailed Comparison
Lithium-ion 18650 batteries and alkaline AA batteries have very different characteristics when it comes to voltage, capacity, size, applications and more. This article provides an in-depth comparison to clarify if 18650 is the same as AA.
Key Differences Between 18650 and AA Batteries
While both 18650 and AA batteries are cylindrical batteries used to power various devices, they have some notable differences:
- Voltage: 18650 batteries have a higher nominal voltage of 3.7V, compared to 1.5V for a standard AA battery.
- Capacity: 18650 typically offers higher capacity, ranging from 1,500mAh to over 3,000mAh. AA batteries range between 1,800 to 3,000mAh.
- Size: The 18650 battery is larger, with 18mm diameter and 65mm length, versus 14mm x 50mm for an AA.
- Applications: 18650 batteries are ideal for high-drain devices like laptops, flashlights, and even electric vehicles. AA works well for lower power devices like remote controls.
- Rechargeability: The 18650 lithium-ion battery is rechargeable. AA batteries come in rechargeable and non-rechargeable types.
So while both battery types have the same cylindrical shape, the 18650 battery is not equivalent to an AA battery when it comes to specifications and performance.
What is a 18650 Battery?
The term 18650 refers to the size and shape of the cylindrical lithium-ion battery rather than the battery chemistry. The “18” indicates a diameter of 18mm. The “65” means the battery is 65mm tall.
Advantages of 18650 Batteries
Compared to AA batteries, 18650 offers:
- Higher energy density enabling longer runtimes
- Higher capacity up to 3,500mAh
- Higher voltages around 3.6 to 3.7V nominal
- Recharge capability up to 1,000 cycles
- High max continuous discharge rates
These characteristics make the 18650 lithium battery suitable for high-drain electronic devices.
Applications of 18650 Battery
Given their high capacity and ability to deliver high currents, 18650 batteries power various gadgets and equipment:
- Laptop battery packs
- High-performance flashlights and headlamps
- Electric vehicles like e-bikes, scooters and cars
- Portable power stations and solar generators
- Vaping devices and mods
Of course capacity, size and connectors vary based on the end device and its power requirements. Protected 18650 batteries also contain monitoring circuitry to regulate voltage and prevent issues like overcharging.
What is an AA Battery?
AA batteries come under the broader category “primary cell” batteries. These are single-use non-rechargeable batteries which must be discarded once they run out of energy.
The AA battery was standardized under IEC 60086 to 14mm diameter and 50mm height hence the “AA” designation. They deliver 1.5V nominal voltage.
While zinc-carbon and alkaline AA batteries dominate the market, other chemistries exist including lithium-iron:
- Alkaline AA – Manganese dioxide chemistry
- Lithium AA – Lithium-iron chemistry with higher voltage and capacity
- Rechargeable AA – Nickel-metal hydride (NiMH) is most common
AA batteries cannot match 18650 batteries in overall performance. But AAs continue serving low-power consumer electronics thanks to easy availability, affordability and universal fit.
Detailed Comparison: 18650 vs AA
Let’s analyze key parameters to understand 18650 vs AA batteries further.
Size and Dimensions
As the name suggests, 18650 lithium-ion batteries measure 18mm in diameter and 65mm tall giving higher volume and surface area:
| Battery | Diameter | Height |
|---|---|---|
| 18650 | 18mm | 65mm |
| AA | 14mm | 50mm |
Clearly, the 18650 battery is larger in dimensions compared to AA size batteries which measure only 14mm by 50mm. The extra room allows more active material giving 18650 high capacity.
Voltage Rating
Standard AA batteries like alkaline and rechargeable NiMH offer just 1.5V nominal voltage and low energy density.
In comparison, 18650 cells utilize lithium-ion chemistry which generates higher voltages around 3.6V to 3.7V nominal. This key property makes 18650 suitable for devices needing over 4V while AA cannot suffice without combining cells in series.
| Battery | Nominal Voltage |
|---|---|
| 18650 | 3.6V to 3.7V |
| Alkaline/Zinc-Carbon AA | 1.5V |
| Rechargeable NiMH AA | 1.2V |
You need about 2.5 AA batteries to equal one 18650 battery in terms of voltage.
Capacity Rating
The 18650 battery offers substantially higher capacity thanks to advanced lithium-ion chemistry and extra space for active materials in its package. They can store between 1,500mAh to over 3,500mAh capacity depending on battery grade and construction.
On the other hand, capacity does vary for AA batteries but tops out around 3,000mAh for the best lithium cells. High-capacity rechargeable NiMH AAs reach up to 2,700mAh although most standard cells rate less than 2,000mAh.
| Battery | Typical Capacity Range |
|---|---|
| 18650 lithium-ion | 1,500mAh to 3,500mAh+ |
| Standard Alkaline AA | 1,800mAh to 3,000mAh |
| Rechargeable NiMH AA | 500mAh to 2,700mAh |
Considering dimensions, 18650 batteries provide vastly higher volumetric energy density – that is capacity packed per unit volume measured in Wh/L.
Maximum Discharge Current
This is a major advantage of 18650 over AA size batteries. 18650 cells support discharge currents or loads up to 20A to 30A and even beyond 50A.
This enables powering high-drain vape mods, power tools and battery packs safely. In contrast, the maximum current that can be pulled safely from AA alkaline or NiMH batteries stays below 1A to 3A ratings.
Hence 18650 batteries comfortably beat AA cells when it comes to performance in high-power devices and equipment.
Rechargeability
The majority of AA batteries in circulation consist of alkaline and zinc-carbon primary cells which are not rechargeable. While low self-discharge NiMH AA cells exist, their capacity and current ratings lag 18650 lithium-ion.
18650 batteries feature lithium-ion chemistry which enables repeated recharging – usually around 500 cycles. Good quality cells retain over 60% capacity even after 1,000+ charge cycles if properly maintained.
So 18650 batteries offer a reusable and eco-friendly battery platform compared to piles of discarded single-use AA cells.
18650 vs AA: Which is Better?
Determining whether 18650 or AA serves as the better choice depends mainly on the type of device and its power demands:
- For high-drain electronic gadgets like laptops, large flashlights, power tools and electric vehicles, 18650 lithium cells beat AA batteries in all aspects. The 18650’s high voltage, capacity, current rating and reusability outperform AA batteries.
- For low-drain household electronics like remote controls, wall clocks, computer mice etc, the easily-available AA battery suffices excellently. 18650 would be overkill for such gadgets in terms of capacity and max current delivery.
If the device supports both battery types, 18650 lithium cells serve as the best choice given their well-rounded performance. Consumers also shift towards greener options like rechargeable Lithium cells compared to heavy usage of disposable cells.
But for simple LED flashlights, toys etc, AA primary and rechargeable cells continue fulfilling requirements while keeping device costs affordable.
Conclusion
To conclude, 18650 lithium-ion batteries have very distinct characteristics compared to AA batteries in terms of dimensions, voltage, capacity, discharge rating and reusability.
While both battery platforms serve portable electronics, 18650 technology clearly outperforms AA thanks to advanced lithium-ion chemistry. The 18650’s high capacity density is suitable for high-drain gadgets and electric vehicles.
But the ubiquitous AA battery still fits smaller consumer electronics excellently given easy availability and affordability. So both battery types continue occupying specific application areas based on device power budgets.
