Background

I want to add a solar panel to my naminukas robot so that it can be operate without burning fossil fuels and also to increase time between the need to recharge.

Problem

Solar panel is a great renewable energy source but it needs a lot of surface which makes them not portable.

Solution

Make solar panel foldable so it can use as little space as possible when not in use or for transportation.

There are a lot of ways to make foldable panels. This project focuses on smallest usable panel which can be expanded and collapsed by a single actuator.

Here is a short video demonstrating design and prototyping:

Most of solar cells produce very low voltage (about 0.5V) and a lot of them need to be connected in series to get to usable voltage. Additional problem is that solar cells produce relatively high current (about 5A) and there are only few small voltage regulators which can boost low voltage but can also handle high current. One of such regulators is Pololu U3V70A. It should be able to work with only 6 solar cells like Sunpower C60.