zaro

What is the voltage of an 18650?

Published in 18650 Battery Voltage 2 mins read

The voltage of an 18650 battery is typically considered in two main states: its nominal voltage and its maximum charge voltage.

What is the Voltage of an 18650?

An 18650 lithium-ion battery does not have a single, fixed voltage, but rather a voltage range depending on its state of charge. Understanding these different voltage points is crucial for proper use and charging.

Nominal Voltage

The nominal voltage represents the average or typical operating voltage of an 18650 battery. This is the voltage most commonly associated with the battery type and is used for general specification.

  • For a standard 18650 cell, the nominal voltage is 3.7 volts (V).
  • This voltage provides a consistent power output for most applications throughout the battery's discharge cycle.

Maximum Charge Voltage

The maximum charge voltage refers to the voltage of an 18650 battery when it is fully charged. Charging beyond this point can be dangerous and lead to battery degradation or thermal runaway.

  • A fully charged 18650 cell reaches a maximum voltage of 4.2 volts (V).
  • It is critical to use a compatible charger that stops charging once this voltage is reached to ensure safety and prolong battery life.

Understanding the Voltage Range

The voltage of an 18650 cell gradually decreases as it discharges from its maximum charge voltage (4.2V) down to its discharge cut-off voltage (typically around 2.5V to 3.0V, though not specified in the reference, it's a common characteristic for safe operation), with its nominal voltage (3.7V) being the average during its operational life.

18650 Voltage Overview

Voltage Type Value Description
Nominal Voltage 3.7V The average operating voltage of the battery.
Maximum Charge Voltage 4.2V The voltage when the battery is fully charged.

Voltage in Series Connections

When multiple 18650 batteries are connected in series, their voltages add up. This configuration is common in battery packs for higher voltage applications.

  • Two 18650 batteries in series:
    • Nominal voltage: 3.7V + 3.7V = 7.4V
    • Maximum charge voltage: 4.2V + 4.2V = 8.4V

This capability to combine cells for increased voltage makes 18650 batteries versatile for powering a wide range of electronic devices, from laptops and power tools to electric vehicles.