How to charge 18650 battery?
Table of Contents
Quick Answer
To charge an 18650 lithium-ion battery safely, use a dedicated Li-ion charger that supports CC/CV (constant current/constant voltage) charging and stops at 4.2 V per cell. Insert the battery with correct polarity, charge at a current recommended by the manufacturer (commonly 0.5C or lower), and never exceed the rated voltage or current. Do not charge damaged, over-discharged, or unknown-origin 18650 batteries, and always charge them on a fire-resistant surface.
Introduction
What is an 18650 Battery?
An 18650 battery is a cylindrical lithium-ion rechargeable battery measuring 18 mm in diameter and 65 mm in length, commonly rated at a nominal voltage of 3.6–3.7 V. It is widely used in laptops, power banks, electric vehicles, flashlights, and energy storage systems due to its high energy density and stable discharge performance. Capacity, chemistry (such as NMC or LFP variants), and safety features vary by manufacturer and model.
