The 18650 battery is a cylinder-shaped lithium-ion battery that is part of electronic devices. The dimensions of the battery are 18 mm in diameter, and the length is 2.56 inches. The battery voltage is based on the chemistry used for the battery. The first time the 18650 battery was made was in 1991 by Sony, and it is part of various devices, tools, laptops, etc. Here we will cover detailed features and related factors for the 18650 battery. So let’s get started with the introduction to the 18650 battery.
What is a 18650 battery?
- The 18650 battery is a lithium-ion rechargeable battery, where the lithium-ion cell is configured in a cylinder-shaped structure and has positive and negative electrodes separated through electrolytes.
- The diameter of the battery is 18 mm, and the length is 65 mm. This size makes them useful for electronic devices, like laptops and flashlights, and they are also used for electric vehicles and medical devices.
- Its main features that help to use are good energy storage features, a low self-discharge rate, and a low cost.
18650 Battery Features
18650 Voltage
- The voltage value for the 18650 battery is 3.7 volts, which makes it useful for different uses.
- The normal full charge conditions voltage is called nominal voltage, which is about 3.7 to 3.6 for an 18650 battery. The 3.7V shows that the battery is fully charged and now can be used.
- The 18650 battery has recharging features, so we must check battery voltage at the time of charging, and 4.2 volts beyond can affect the battery.
- The battery’s maximum discharge voltage is 2.5 volts.
| Voltage | Details |
| 2.5V – 4.2V |
Real voltage at time of operation
|
| 3.6V |
Nominal voltage of lithium-ion 18650 batteries
|
| 3.7V |
Nominal voltage of lithium-ion 18650 batteries
|
| 3.2V |
Nominal voltage for lithium iron phosphate (LiFePO4) 18650 batteries
|
| 4.0V – 4.2V |
Complete charged voltage for lithium-ion 18650 batteries
|
| 2.5V – 3.0V | cut-off voltage |
| 2.0V – 2.5V |
Minimum safe operating voltage
|
18650 battery size
- The dimensions for the 18650 battery are 18mm and length is 65mm.
| Specification | Dimension |
| Diameter |
18 mm or 18.0 ± 0.2 mm
|
| Length |
65 mm or 65.0 ± 0.1 mm)
|
| Total Volume | 16.5 cm³ |
18650 battery capacity
|
Capacity (mAh)
|
Details |
| 1500 – 2000 mAh |
Low capacity 18650 batteries part of flashlights, remote controls, etc
|
| 2100 – 2600 mAh |
Standard capacity 18650 batteries part of vape mods, toys, etc
|
| 2700 – 3200 mAh |
High capacity 18650 batteries used for small power tools, trimmers,
|
| 3300 – 3500 mAh |
Ultra-high capacity 18650 batteries, electronics cars, mobile phones, etc
|
What’s the difference between an 18650 battery and an AA battery?
Dimension
- The 18650 lithium battery diameter is 18 mm, and the length is 65 mm. An AA battery has a diameter of 14 mm and a length of 50 mm. The 1865 battery is larger in size as compared to AA batteries.
Chemistry
- The 18650 battery is a rechargeable lithium-ion battery made with lithium-ion phosphate or NiCoMn ternary material. AA batteries are alkaline batteries, zinc-carbon batteries, nickel-metal hydride batteries (NiMH), and lithium-ion batteries.
Voltage
- Both have different voltages; the 18650 battery voltage is 3.7 volts, and the AA battery is a volts of 1.5V.
Capacity
- 18650 battery capacity is 1800–3500 mAh, and AA battery capacity range is 1700–2700 mAh, and the alkaline AA battery has a capacity of about 600–2700 mAh.
Performance
- The 18650 battery has high capacity and more energy, and as a result, is used for a longer working life with a complete charge. An AA battery has low capacity but is non-rechargeable and is used for one-time use.
Lifespan
- • An AA alkaline battery is disposable and does not have recharging features. The 18650 battery is charged/discharged about 800-1000 times.
Can we use an AA battery for 18650 batteries?
- We cannot use the 18650 battery for the AA battery; both have different voltages. The 18650 battery voltage is 3.7 volts, and the AA battery voltage is 1.5 volts. The 18650 battery is replaceable with a 21700 battery.
18650 Battery Types
- The lithium-ion 18650 battery has recharging features and is based on lithium-ion movement for electrodes at the time of charge and discharge. Battery chemistry is lithium cobalt oxide (LiCoO₂) and an anode made with graphite that is separated with electrolyte.
Features
- • The Li-ion 18650 battery has high energy density, provides high power for compact design, and is used for portable devices and high-demand uses.
- It has a longer working life and has many charge-discharge cycles for performance maintenance.
- It has a low self-discharge rate; the Li-ion 18650 battery comes with a charge for a longer time if not in use.
LiFePO4 18650 battery
- A LiFePO4 18650 battery is a rechargeable battery and uses iron phosphate as a cathode material, different from conventional lithium-ion batteries. It uses lithium-ion moving between cathode LiFePO₄ and anode at the time of the charging and discharging cycle, storing and properly releasing energy.
Features
- It has good thermal features and a chemically stable nature, minimizes the chances of risk of thermal runaway, and provides safer features than other types of lithium-ion batteries.
- It has a longer working life with high charge-discharge cycles and works for a longer time. It has iron phosphate in the cathode that is stable in nature and high temperatures for constant working.
18650 LiPo battery
- Lithium Polymer (LiPo) 18650 battery denoted a certain recharging battery type for the composition use of polymer electrolyte rather than liquid electrolyte for the standard lithium-ion battery.
- This battery has solid or gel-like materials as electrolytes and a more flexible and compact design than other cylindrical lithium-ion batteries.
Features
- This battery has a flexible form factor since it uses polymer electrolyte and provides different shapes and sizes for different designs.
- This battery has high energy density and provides power based on size and weight and is good for devices where high power output is needed.
Nickel-metal hydride 18650 battery
- The nickel-metal hydride (NiMH) 18650 battery is a rechargeable battery that uses a nickel oxyhydroxide positive electrode, a hydrogen-absorbing negative electrode, and an alkaline electrolyte.
- This battery is used for storing energy; reversible electrochemical reactions occur between nickel oxyhydroxide and hydrogen ions.
Features
- NiMH 18650 batteries have higher energy density than conventional nickel-cadmium batteries and have high power with the same factor.
- It is environmentally friendly, does not have toxic metals such as cadmium, and has fewer disposal issues.
- It is low cost with a working life since it has recharging features.
High-drain 18650 battery
The high-drain 18650 battery is a special recharging power supply made to provide high current output. As compared to standard batteries, they are high-drain types used to fulfill the demand for devices where fast and high energy discharge is needed.
Features
- High-drain 18650 battery comes with fast and substantial bursts of energy and is best for devices that have high performance, like power flashlights and vaping devices.
- It is used for high-end vaping mods, power tools, and high-performance flashlights and has optimal functionality.
How many amps can an 18650 battery put out?
- The 18650 battery has features for producing 2500 mAh to 3500 mAh. High amps output defines that battery generating high power. The main factors that are important for battery voltage are.
Operating temperature
- Battery voltage is based on active materials in battery function. So ambient temperatures that affect the activity of active materials have affected battery voltage.
Load power
- The voltage and power of the battery are constant values; higher power and a larger current are needed, and the voltage will reduce to provide low power, and a high load can damage the battery.
Battery life
- The main way to protect against errors is by checking battery performance. If the battery is not to be used for safe features, it will not retain charge when used.
What is the highest output 18650 battery?
18650 battery comes with a high output power of 3500 mAh and is used for high- and low-power applications. The output power for the 18650 rechargeable battery is 19W, the maximum output current is 7 amperes, and the high output voltage is 4.2V.
How many volts are 2 18650 batteries?
- The nominal voltage for the 18650 battery is 37 volts, and the battery pack with 2 18650 batteries in series combination has a voltage of 7.4 volts. The maximum voltage for an 18650 battery is 4.2 volts, and the maximum voltage value can be about 8.4 volts (4.2V x 2) for 2 batteries in a series combination.
- The 3 batteries in series provide 12 volts; the series combination does not affect capacity but increases the voltage. Parallel combination increases battery capacity, not voltage.
At what voltage is a 3.7 V battery dead?
- If the 3.7 V 18650 battery voltage reduces to 3 volts, it will become dead. Since the protection board is not discharging, it prevents the battery from getting overdischarged. The end-of-voltage of 18650 is 2.75 volts. For normal conditions, if battery voltage falls to 0.875 times the nominal voltage, it must be charged in time. The 18650 battery for 4.2 volts can be dead when its voltage is 3.0 volts.
- Note that some 18650 batteries do not come with the cut-off circuit. So do not discharge beyond 3 volts, and the battery voltage will lose fast and cause an irreversible effect on the battery as a result of over-discharge.
What voltage should I charge a 3.7 V lithium-ion battery?
- The best is that it charges a 3.7V lithium-ion battery at 4.2 volts since it has a full charging voltage of 4.2 volts. With that, that 3.7V lithium-ion battery should be charged with the use of a 4.2V constant voltage charging mode.
- If the charging voltage is higher than 4.2 volts, it overcharges the battery overcharged and also damages the battery.
Can we charge a 3.7 V battery with a 4.2 V charger?
- We can charge a 3.7V lithium-ion battery with a 4.2V charger. For using a charger for battery charging, the output voltage of the charger needs to be the same as the high voltage of the battery. If the output voltage of the charger is higher as compared to the maximum voltage of the battery, it will be damaged.
- If the output voltage of the charger is less than the battery voltage, the battery is not completely charged. The charge cut-off voltage of a 3.7V battery is 4.2 volts. So it is good to use a 4.2-volt charger since a 3.7V battery charges, and if we use a 5V charger for charging a 3.7V battery, it results in overcharging.
FAQs
What are the capacity ranges for 18650 batteries?
- The 18650 battery range is 1500 mAh to 3500 mAh. If the battery comes with mAh and stores energy in the charging process for providing a longer time. The battery will come with a high capacity, needing to be charged more than a low mAh battery.
Are all 18650 batteries the same?
- The 18650 batteries come with different chemical compositions. These batteries are lithium-ion (Li-ion) and lithium-ion phosphate (LiFePO₄). 4). The 18650 battery features are different for different devices.
Do I choose an 18650 battery capacity for my device?
- The main features are power and certain features for electronic devices with 18650 battery specs. Battery should be based on device features, and also check battery runtime and battery expenses.
Can I use different 18650 battery brands together?
- It is not good to use batteries for different models. If the 18650 battery features are the same, the inner system of the battery has different resistance, charge, or discharge capacity.
Read also
