Solar Panels

Finished Solar Panel

The solar panels provide approximately 1 Watt of power at 5V in full sunlight. They can be used to power motors directly, or with a solarengine in between the panel and the motor for more flexibility. They can also be used to charge a powerpack.

The amount of power they can generate from indoor lighting is about .1 % of what they generate in full sun, because there is far less energy in indoor lighting than in sunlight.

Sourcing Parts

  1. 1 Watt Solar Panel from SEEED Studio. Mouser used to sell these in Denmark but then stopped due to some regulation but won't say what that regulation is. Any 1 watt solar panel at 5-6V will do. If you find a good alternative, let us know! Seed Studio panel on Mouser

  2. Miscellaneous bits:

    • XT30 Plug (female) connector
    • 5 hole length of Plumber's Strap
    • Epoxy, plasti-weld, or other strong adhesive capable of holding smooth surfaces together at high temperatures.

Assembly

Panel and Parts

Tools Needed:

  • Soldering iron
  • Wire stripper
  • Bit of rough sandpaper

Assembly Instructions:

  1. Cut the leads of the solar panel to the length you'll need to position the XT30 connector properly. Solder the leads to the XT30 being mindful of the correct polarity. Panel and strap
  2. Use the sandpaper to quickly roughen up the back of the solar panel where the strap will be bonded. The scratches give the epoxy something to grip.

  3. Solder the wires from the solar panel onto the XT30 connector, being mindful to solder the red lead to the positive terminal on the XT30. Connector and strap laid out

  4. Mix up your epoxy and apply it to the back of the solar panel where the strap will contact it. Place the Plumber's strap against it so that two of its holes extend out from the panel (so that each can take a snap-rivet). Cover the strap with epoxy so it has a firm bond with the panel. Soldered and glued panel

  5. Orient the XT30 connector at about 45 degrees upwards from the back of the Plumber's strap, and then stick the back of it down into the epoxy and paint epoxy over it and the wires. It helps to connect the terminal loosely to an XT30 patch cable, so you can control its position by propping it between something to hold it in place while the glue dries. Make sure epoxy covers the wires on the back of the XT30 connector so it insulates them and protects them from being strained. Also cover the other end of the wire where it connects to the solar panel so it has strain relief the whole way. Glued solar panel

Desired Improvements

  • It would be great to experiment with higher efficiency (and smaller and less heavy) solar panels in the 1 watt range, as long as their cost stays low.
  • There are solar panels that work better with indoor light frequencies, but we haven't found any that are inexpensive. It would be nice if we could find some that can be used with LED work lights indoors on rainy days. This would give us a lot more flexibility when planning workshops.
  • Should we try integrating the solarengine circuitry into the solar panels, thereby simplifying the construction kit by removing a major component? It would make things simpler in some ways, but more complex to build in others. Would it further "black box" the solarengine and the panen in a way that is potentially confusing for kids?

Past Revisions

  • The first revision just had the outputs soldered to an XT30 connector, slathered in epoxy. (We can use hot glue in Denmark. But in very sunny and warm places like Colorodo, panels get very hot and will quickly melt the glue.) These had Left and Right versions because the plumber's strap was either left or right of the connector, which created a problem if you need one type but couldn't immediately find it. This is why current revisions have the strap at the center and the connector glued on top of it at a 45 degree angle, thereby simplifying things.

Solar Panel v.1