18650 Battery Guide
Lithium Ion 18650 Cells
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What is an 18650?
At it’s most basic an 18650 is a Li-Ion cylindrical cell that uses its dimensions as it’s designation. The first two digits are the approximate diameter, in this case 18mm and the following 3 digits are the approximate height in tenths of millimeters, in this case 65mm. Hence the 18 65 0 designation. These cells have a nominal open circuit voltage of 3.7V per cell and a full charge voltage of 4.2V.
18650 cells have been used for some time in laptops, power tool batteries and numerous other battery pack applications. However, they are increasingly finding there way into more and more diverse consumer devices such as high powered LED torches to door bells.
Some of the advantages of Li-Ion include a high energy density, low maintenance, low self discharge rates and depending on the cell a high maximum continuous discharge rate.
“PCM” or “BMS”
Generally Li-Ion cells in most consumer devices will have a protection circuit module (PCM or PCB). The PCM will help to protect the cells or battery pack from over charging, over discharge and over current and short protection. The PCM will help protect the user from potential fire and explosion.
A battery management system (BMS) is a similar circuit, with far more features. A BMS can or may monitor such things as the batteries charge state, balance the battery, report data, temperature, voltage, state of health.
It is extremely important to use caution when working with and using lithium ion batteries as they are very sensitive to charging characteristics and may explode, burn, or can cause a fire if misused or mishandled.
We highly recommend reading our Li-Ion precautions sheet on handling Li-Ion.
How do I select an 18650?
There are many different types of Li-ION (Lithium-Ion) cells available, all designed to do a different job and generally differentiated by the chemical abbreviation, 6 of the most common are listed below:
- LiCoO2 (Lithium Cobalt Oxide – LCO)
- LiMn2O4 (Lithium Manganese Oxide – LMO)
- LiNiMnCoO2 (Lithium Nickel Manganese Cobalt Oxide – NMC)
- LiNiCoAlO2 (Lithium Nickel Cobalt Aluminum Oxide – NCA)
- Li2TiO3 (Lithium Titanate – LTO)
- LiFePO4 (Lithium Iron Phosphate – LFP)
Selecting the right Li-ION cell for your job comes down to a number of different factors depending on what you want the 18650 to do. Do you want to be able to discharge a high current in a short burst, or does your 18650 need to deliver a long cycle life? Lets take a look at some of the best quality cells on the market and some of their key features.
18650’s Available
SAMSUNG INR18650-35E 3500mAh Battery
The SAMSUNG INR18650-35E is a high capacity 3500mAh cell, with a maximum continuous discharge rate of 8000mA. The cell is ideal for applications such as E-Bikes, Laptops & Notebook Computers, Robotics and other medium drain applications.
SAMSUNG INR18650-30Q 3000mAh Battery
The SAMSUNG INR18650-30Q is a high capacity 3000mAh cell, with a maximum continuous discharge rate of 15,000mA. The cell is ideal for applications such as E-Bikes, scooters and other medium to high drain applications.
SAMSUNG ICR18650-26JM 2600mAh Battery
The SAMSUNG ICR18650-26JM is a low rate capacity 2600mAh cell, with a maximum continuous discharge rate of 5200mA. The cell is ideal for applications such as Laptops & Notebook Computers, bike lights or lower discharge rate applications.
PANASONIC NCR18650B 3400mAh Battery
The PANASONIC NCR18650B is a high capacity 3400mAh cell, with a maximum continuous discharge rate of 4900mA.The cell is ideal for applications such as E-Bikes, Laptops & Notebook Computers, Robotics and other medium drain applications.
SAMSUNG INR18650-25R 2500mAh Battery
The SAMSUNG INR18650-25R is a high rate capacity 2500mAh cell, with a maximum continuous discharge rate of 20,000mA. The cell is ideal for applications such as power packs, high-output power banks, power tools, and high powered flashlights.
Capacity & Discharge Rates Chart
To make this easier for you we have listed some of the most common 18650 cells available on the market. The following chart can be sorted by the capacity, maximum continuous discharge rate or brand.
*Please note that not all of these cells are always available in stock.
Samsung SDI Safety Information
“Charging, Use, and Handling of Small-Sized Lithium-Ion Batteries”