A simple home-made 5V solar power charger suitable for any mobile phone.


Made by a small group of students in Berlin who are also part of the international 'open source ecology' network the r0g_solar.mini is a fast and powerful pocketbook size charger that also simultaneously charges 4 x AA ni-cad batteries.

Although there are numerous mobile solar power chargers on the market, the r0g_solar.mini was developed as a test and demo model of a charger that, with a small amount of training, can be built by anybody and uses common components that are readily available. The design the r0g_solar.mini is also open source, so it's copying, use and distribution - including development and marketing by anybody is both allowed and encouraged.


Let us develop the Solar.mini further at github.com/opencultureagency/Solar.mini/


Refer to Open Hardware Guide for images

Project: Solar Charger Date: 26th November 2016 CC-BY-SA (digital) CERN OHL (hardware) Open Hardware Guide

[Pictures] + Diagram SolarCharger Steps:

  1. Draw diagram of the charger for easy understanding (optional)
  2. Open your ASKotek kit for tools
  3. Get circuit board and solder the diode and LED in place
  4. Solder the resistor in the front of the LED
  5. Connect to the LED lights to the negative side
  6. Solder the capacitors with long side connected to the outer regulator legs
  7. Fix regulator with black side facing you and connect between diode and resistor
  8. Connect the other side of the regulator to the capacitor (long side connected)
  9. Connect all the negatives sides together
  10. Cross the middle pin to the negative with side to LED
  11. Behind the diode (1. option) or to the right capacitor connect the positive wire from solar panel
  12. And the other negative to the negative side
  13. Connect female USB. Positive on red and negative on black
  14. Test the Solar Charger in the sun


  1. Color-coded wire (red and black)
  2. Soldering iron
  3. Soldering grease
  4. Soldering Sucker
  5. Helping hand (magnifier & clamps)
  6. Soldering wires


  1. Solar panel 8V +/- 250mA
  2. Resistor 1200 Ohm (1. option) Resistor 600 Ohm (2. option)
  3. 1 Diode
  4. Capacitor one 10 µF
  5. Capacitor two 100 µF
  6. Female USB
  7. 5V Regulator
  8. Circuit board
  9. LED light (red one)

Tips and Usage

  1. Can be used for charging phones
  2. Environmentally friendly
  3. Saves money
  4. Test with mobile phone or LED light Open for improvements

Build a casing Open Questions: How to find + and – wires on female USB (if not red and black)? What if somebody is surrounded with no material, how to use old electronics?