DIY Solar Trickle Chargers

Take apart the solar garden lights and remove the solar cells. They are usually coated in plastic and are very durable.

Use a multimeter to check the voltage output from the cells. A solar garden light PV cell will usually have an output of approximately 2.5 volts, which is ideal for this project.

Tear several strips (two at a time) from a recycled floppy drive cable and split the ends, so you have two wires exposed at each end.

Using the wire, solder the two PV cells together, ensuring you attach the wiring to each lens correctly, positive post to positive post and negative post to negative post. Then check the output with a multimeter. It should give a reading of approximately 5 volts.

Connect the two other cells in parallel to the configuration by using extra wiring to act as a bridge, soldering a negative post to positive post and negative post to positive post. It is best to leave the last bridge connection until you have placed all the PV cells into the plastic sleeve pockets, to enable easier placement.

Solder color-coded wiring to the PV cells. Attach black wire to the negative post and a red wire to the positive post, at one end of the configuration.

Take your mobile phone adapter and snip the wire to reveal the red (positive) and black (negative) wiring. Solder these to the color-coded wires already attached to the solar unit.

Place the solar unit in the plastic sleeve pockets. You will need to cut slots in the plastic in order to accommodate connecting wiring and cell placement. Solder the remaining wire bridge to close the solar circuit and fix down with clear tape.

Attach the unit to the multimeter and check the output reading, which should be approximately 5 volts for this configuration.

Fix electrical tape around the edges of the plastic sleeve for reinforcement and plug your adapter into your mobile phone.

Place the solar cells in sunlight and charge your phone.