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Green rectangular circuit board with two USB ports and battery terminals

Ruth's sister

Ruth's sister 270B4NB905907 international power cord

SKU CH-V9RC-9PFW9

A DIY power-bank circuit board that boosts a 3.7 V lithium cell to dual USB outputs of 5 V at up to 2.4 A total

  • Converts 3.7V lithium cells to stable 5V USB output
  • Single port delivers up to 2.1A for phone charging
  • Dual ports supply up to 2.4A combined for multiple devices
  • Accepts standard 5V charger input for simple recharging
  • Minimum 100mA load required to maintain regulation

DIY power-bank boost module

This PCB board converts a 3.7 V lithium cell into a 5 V USB supply rated up to 2.1 A on a single port or 2.4 A combined across two ports. It is intended for hobbyists building their own portable chargers for phones or tablets.

Input and output limits

The module only accepts a 5 V charger for recharging the cell and will not work with PD or other fast-charge protocols. A minimum load of 100 mA is required, so very low-current devices such as Bluetooth headsets or MP3 players cannot be powered.

Battery and wiring checks

You must use a 3.7 V lithium battery rated at 3C or higher; aged or salvaged cells from laptops, drills or EVs should be tested with a multimeter before connection. Reverse polarity, series wiring and mixed cell types are strictly prohibited.

Highlights

  • Converts 3.7V lithium cells to stable 5V USB output
  • Single port delivers up to 2.1A for phone charging
  • Dual ports supply up to 2.4A combined for multiple devices
  • Accepts standard 5V charger input for simple recharging
  • Minimum 100mA load required to maintain regulation

Specifications

No published specifications for this item yet.

Questions about this item

Which output should I use if I need up to 2.1 A for one device?

Use the single USB port, which delivers 5 V at 0.1–2.1 A maximum.

What input voltage does the board expect from a charger?

The board accepts a 5 V input; PD chargers are not supported.

What is the minimum load current the board can recognise?

The minimum recognition current is 100 mA, so very low-draw devices such as Bluetooth peripherals will not be powered.

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