While you can power a Raspberry Pi through the dedicated USB port, it's not always practical. In certain situations, drawing power from a small and thin lithium-polymer (LiPo) battery makes better sense. This is especially true for projects based on Raspberry Pi Zero, because of the board's modest power requirements. The good news is that powering the Raspberry Pi Zero using a regular 3.7V LiPo battery is cheap and relatively straightforward (some soldering is required, though).
Incorrect wiring or wrong output voltage can damage the Raspberry Pi or the battery. Working with LiPo batteries can be dangerous. MAKE SURE YOU KNOW WHAT YOU'RE DOING, AND PROCEED AT YOUR OWN RISK!
Before you start, make sure you have everything you need:
- lithium-polymer 3.7V battery
- 18650 charger and 5V converter module (similar to this one)
- soldering iron and soldering paraphernalia
The wiring diagram is pretty simple:
┌───────────┐ ┌───────────────┐ ┌────────┐ │ GPIO 2 ├──────────┤ VOUT+ BAT+├──────┤+ │ │ │ │ │ │ │ │ GPIO 6 ├──Switch──┤ VOUT- BAT-├──────┤- │ │ │ └───────────────┘ └────────┘ │ │ 18650 module LiPo battery │ │ │ │ └───────────┘ Raspberry Pi Zero
Start with wiring the battery to the 18650 charger and 5V converter module (18650 module, for short). Do not connect or solder the module to the Raspberry Pi Zero just yet. Why? Because the 18650 module can deliver up to 12V, but you need only 5V to power the Raspberry Pi Zero. So before you wire the module to the Raspberry Pi pins, you must adjust the output voltage. To do this, connect the multimeter to the 18650 module's
VOUT+ terminals, then use a small screwdriver to adjust the output voltage by rotating the small potentiometer that sits right next to the
VOUT- terminal. Once the module is configured to output 5V, you can wire it to the correct Raspberry Pi pins.
And that's all there is to it. Charge the battery using the mini-USB port of the 18650 module, flip the switch, and watch the Raspberry Pi Zero booting while congratulating yourself on a job well done.