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Living off-grid: how to build solar lights

Solar-powered lights are becoming increasingly popular.  They can be seen on streets, like the one at right, or along walkways, paths, in the backyard.


They is no cost to operate solar lights.  They don’t require connection to the utility company, and can be portable.

Although you can purchase small backyard units relatively inexpensively, you might want to consider making your own. You’ll have greater choice of style, size, and brightness, and it can be a fun, learning experience.

Make your own

You will need these components:

  • Small solar photovoltaic (PV) panel.
  • One or two ~ 2 volts Light Emitting Diodes (LEDs).
  • Two or four AA 1.2 volt rechargable batteries.
  • Transistors, Resistors and power diode.
  • Small pieces of wire to connect the parts together.
  • Circuit board: cut into small squares.

If you like the idea of customizing your own fully-functional solar light, you can get started right away by following the steps below.

1. Getting the schematics right

Before getting to the specifics, a step-up switching regulator circuit is needed to control the LED. If you don’t have one, you can build one yourself using this schematic diagram if you have a TL499A controller, toroid inductor, and various resistors and capacitors that the diagram requires. 

If you want it to automatically turn on at night for the yard, you will need to use a photoresistor to detect darkness instead. This guide will use a beer bottle as the container so be sure to make the regulator circuit small enough to fit in the bottle.

2. Soldering process

Try to find a 1W LED which should cost around $4 and then solder two wires to the cathode and anode leads of the LED. The wires should then be connected to the regulator circuit. 

You’ll also need a solar module that is 3V and can be purchased at an electronics store for $3. Apply some soldering to the positive and negative terminals of the solar module you just bought. The diode will be attached to the positive terminal pad and a length of wire will be connected to the negative terminal.

The battery pack which will power the device should be connected to the final pole of the switch. Make sure all the other connections are secured.

3. Setting up the light

The finished product in step 2 will go inside the bottle or container of your choosing. If done correctly, you should have all the components inside except for the switch. 

Set the switch to the solar module connection and put the bottle under the sun to charge the battery pack. After a few hours, it should be fully charged and sliding the switch to the circuit should cause the LED to light up.

The light duration varies depending on the components used. You can make multiple solar lights to boost the effectiveness and creating them should cost less than $30 to make.

Originally posted at DIY-Solar-Power.net.