A mini regulator for solar charging of your gadgets
















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With this mini regulator, you can charge your mp3 or other gadgets using solar power. It uses a 7805 regulator chip to deliver power to your all important gadgets. It's water proof too, so you can take it anywhere, even to the bottom of your coffee cup, a place my mp3 players end up too often!

Here's what you'll need :

  • A 7805 regulator chip
  • 2 capacitors around 1uf
  • A heat-sink to suit the regulator
  • A USB/ charger cable for whatever you want to charge.
  • Hot melt glue
  • 2 core wire to connect from the regulator to the solar panel.


Step 1: Bend the regulator pins back:

Bend the regulator pins back on themselves :



Bolt the regulator down using the bolt hole in the heat-sink.


Tape a piece of insulation tape over the screw head and metal part of the regulator to insulate it from the rest of the circuit.


Step 2: Bend the pins out on the capacitors

Bend the pins on the capacitors so that you can solder the two negative connections together.


Solder the two negatives together:



When you're done, place the two capacitors into the heat-sink, next to the regulator:


Step 3:

I used an old two core mains cable for the input wires. Strip them so that they're long enough to reach from the capacitors to the regulator and tin them.


Solder the negative (black or blue) to the middle pin.



Solder the positive to the input pin of the regulator (see diagram):

Click to enlarge the diagram
Step 4: Solder the output wires on.

Strip the outer sheath of your USB cable off. There should be four coloured wires and one bare copper wire or foil.


There will be a red and a black wire, you want to keep these and the bare wire, cut  the other two off where you stripped the out sheath to. Strip the red wire down to long enough to reach from the capacitors to the regulators output  pin.
The black wire can be much shorter, it just has to be connected to the middle pin (ground).


Connect the bare wire to the black negative wire.


Tin both of the wires.
Solder the red wire onto the capacitor + lead beneath it and to the output pin of the regulator..


Solder the black wire to the ground wire (middle).


Hopefully it should be clear with the diagram.


Step 5: Seal it up, if it works.

Test it first! Connect the input wires to your solar panel, and plug the output into whatever you want to charge. I used a 20W solar panel which is a bit too big for this, but OK for testing. In reality, you want a 2 - 5W solar panel for this.


If it's all good, you can seal it up using hot melt glue or similar.