18650 Battery Equivalents

There are not many alternative names for the 18650 battery. The model number used by some manufacturers may be slightly different for instance Samsung 20S or Samsung 25R and Sony Murata VTC5D. Other different manufacturer names include SkyRC MC3000, Efest LUC V8 Double LCD, Gryfalcon All-88 and Xtar Dragon VP4 Plus just to name a few. We will discuss other manufacturer naming conventions below but first the battery specifics.

Generic 18650 Battery Specifications

• Diameter: 18mm
• Length: 65mm
• Capacity: 2500mAh-5000mAh
• Nominal Voltage: 3.2V-3.7V
• Minimum Discharge Voltage: 3V
• Maximum Discharge current: 1C
• Charging Voltage: 4.2V (maximum)
• Charging current: 0.5C
• Charging Time: 3 hours
• Weight: 48g 

Manufacturers like to overstate their capacity so the variation can be quite large. Check reviews and forums for true values. Voltage can vary greatly from one manufacturer to the next. Different applications and devices need different voltage and current so check to see if a specific 18650 battery is needed for your particular device. These batteries have proved popular over general use lithium batteries due to their superior properties including current stability, voltage, recharge cycles and storage life.

C rating and mAh of an 18650 Battery

Two common terms when dealing with batteries are C rating and mAh. If an 18650 cell is rated at 2550mAh means that when we consume 2.550A from the battery it will last for 1 hour and similarly if we consume only 0.255A from the battery it will last for 10 hours. We can use these ratings to determine how long a particular battery will last for a device. C rating for a 18650 battery is usually 1C. We can consume a maximum of 2.55A from the battery. This is because Amp hour rating  multiplied by C rating gives us the maximum current that can be used. 

18650 Battery Chemistry

Naming of 18650 batteries include abbreviations like INR, IMR, ICR, or IFR. These naming conventions are indications of battery chemistry.

IMR 18650 Battery Specifications

• Chemistry: LiMn₂0₄ (Lithium Manganese Oxide)
• Nominal voltage: 3.6 – 3.7 V
• Maximum charging voltage: 4.2 V

INR 18650 Battery Specifications

• Chemistry: LiNiMnCoO₂ (Lithium Manganese Nickel)
• Nominal voltage: 3.6 – 3.7 V
• Maximum charging voltage: 4.2 V

IFR 18650 Battery Specifications

• Chemistry: LiFePO₄ (Lithium Iron Phosphate)
• Nominal voltage: 3.2 – 3.3 V per cell, with the
• Maximum charging voltage: 3.5 – 3.6 V

ICR 18650 Battery Specifications

• Chemistry: LiCoO₂ (Lithium Cobalt Oxide)
• Nominal voltage: 3.6 – 3.7 V
• Maximum charging voltage: 4.2 V

Note: there are other chemistries available including hybrid technologies like:(LiNiCoO₂), (LiNiCoAlO₂) etc but these are not popular in the consumer market.

Flat vs Raised Top

The 18650 battery can come in either a flat top (positive) or button top. Depending on your device it may support both types. Check documentation and the battery cavity for compatibility. Most devices support both the button and flat top.

Charging an 18650 Battery

Charging voltage of an 18650 cell is 4.2V and recommended charging current is 1A (0.5C). Newer technology 18650 battery chargers are intelligent and can sense the battery type, chemistry, condition etc. They are capable of charging most consumer type batteries like NiMH AA, NiCd AAA etc.

Protected 18650 vs Non-Protected 18650

Lithium-ion batteries are very sensitive to charging and temperature fluctuations. You have a choice when buying 18650 models to get built-in protective circuit. This protective circuit monitors the conditions of the battery and adjusts charging conditions accordingly. Protective circuits require more room and will slightly decrease the capacity. These protective circuits are a small price to pay for peace of mind and safety.

Samsung INR18650 Batteries

Samsung INR18650-25R 18650 or Samsung 25R is one of the most popular batteries on the market.. A stable continuous current of 20A. With a capacity of 2500mAh and CDR of 20A, this battery provides a great current rating and superior capacity. Samsung is a trusted name and the quality control is standard to none. This is by far the safest 18650 battery on the market in 2021.