Turning Batteries Into Powerbanks

Lithium-based rechargeable batteries feature high energy density and can store huge amounts of energy in a small space. But only when equipped with additional electronic circuitry will they become a useful powerbank.

Turning Batteries in Powerbanks

A rechargeable battery acts like the raw storage tank of a powerbank. What’s missing are the electronics to easily charge and discharge these batteries. Only then will a battery become a powerbank.

Required Components

A powerbank adds the following components:

  • Charger: accepts a common input voltage (such as USB voltages) and converts it to the charging voltage and current required for safely charging the internal battery.
  • Battery Management System (BMS): safeguards the battery and protects it from over-charging, over-discharging, and short-circuiting.
  • Output Voltage Converter: Circuitry that converts the native battery voltage to useful voltages, i.e. 5V USB for charging USB devices, or even digital logic to support a variety of quick charging protocols.

Optional Components

Typically, powerbanks also include the following optional components:

  • Visuals: LED Bars, digital displays, etc. to indicate the current state of charge.
  • Button: turns on the electronics whenever power needs to be drawn from the powerbank. This way, the electronics can go to sleep when not in use. This prevents the battery from silently discharging over time.

DIY Powerbank

Powerbanks can be easily designed and built. The required components are readily available. This section introduces and explains typical examples.

Always keep in mind that powerbanks deal with huge amounts of energy and can be dangerous when built improperly. Lithium batteries used inside a powerbank can draw huge currents. When the batteries are not properly protected by a BMS, or when wiring or construction is done improperly, DIY powerbanks can explode or catch fire. Consider building your own powerbank only if you are fully aware of the risks and have appropriate skills.


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(content created May 02, 2024)