Power your Pi Pico with solar Self-Sufficient

Powering your Pi Pico with solar may not solve the current energy crisis, but it will save you from changing or recharging batteries

- Bernhard Bablok

My idea to add solar power to a Raspberry Pi Pico started with a previous project [1] that displayed the time, temperature, and humidity on an e-paper display with a Pi Pico integrated on the back. For that project, I used a Badger 2040 [2] by Pimoroni (Figure 1).

The system wakes up once a minute, updates the sensor values and time, and then falls back into deep sleep. Figure 2 shows the power draw for the Badger 2040: seven seconds of activity at approximately 27mA of power consumption compared to 53 seconds at 6.5mA. The relatively low power consumption prompted me to consider using a solar panel to power this setup even in less favorable light conditions.

Solar Panels

Some brief research showed that small solar panels like the one shown in Figure 3 are available from the usual sources for a relatively low price. For my test, I chose a panel by Pimoroni that delivers a nominal 100mA at 3V. For a Pi Pico without anything attached, 3V works fine, and the Badger 2040 is also happy with this, so in theory this should work. Unfortunately, the available power is very rarely equivalent to the nominal output, which means that things are not quite so simple.