Solar Energy, PV trackers description

1. Solar Panel Phone Charger
AUTHORED BY: HALLE, JACOB AND TRENTON

2. Brief History On Solar Energy
 The history of Photovoltaic Energy (Solar Cells) started way back in 1876. When William
Grylls Adams a professor of Natural Philosophy at King’s College, London along with a
student of his, Richard Day, discovered that when selenium was exposed to light, it
produced electricity.
 Even though we now know selenium cells are not efficient, the discovery was the most far
reaching importance scientifically which proved that light, without heat or moving parts,
could be converted into electricity.
 Then in 1953, Calvin Fuller, Gerald Pearson, and Daryl Chapin all Chemist at AT &T Bell
Laboratory, discovered the silicon solar cell by diffusing Boron into Silicon. This cell actually
produced enough electricity and was efficient enough to run small electrical devices.
 In the late 1950's and early 1960's satellites in the USA's and Soviet's space program were
powered by solar cells and in the late 1960's solar power was basically the standard for
powering space bound satellites.
 In the early 1970's Exxon spearheaded a research to lower to cost of solar cells. This
brought the price down from $100 per watt to around $20 per watt.
 Recently new technology has given us screen printed solar cells, and a solar fabric that
can be used to side a house, even solar shingles that install on our roofs, and portable
panel for small electronics. (e.g Solar Panel Phone Charger).
 International markets have opened up and solar panel manufacturers are now playing a
key role in the solar power industry

3. What is Solar Cell ?
 Solar cells convert the sun’s energy into
electricity. Whether they’re orbiting our
planet on satellites, they rely on the
photoelectric effect: the ability of matter to
emit electrons when a light is shone on it.

4. How do Solar Cell Work ?
 Silicon is a semi-conductor, meaning that it shares some of the properties of metals and some of those of an
electrical insulator, making it a key ingredient in solar cells. Let’s take a closer look at what happens when the
sun shines onto a solar cell.
 Sunlight is composed of miniscule particles called photons and as these hit the silicon atoms of the solar cell,
they transfer their energy to loose electrons, knocking them clean off the atoms.
 Freeing up electrons is however only half the work of a solar cell: it then needs to herd these stray electrons
into an electric current. This involves creating an electrical imbalance within the cell, which acts a bit like a
slope down which the electrons will flow in the same direction.
 This imbalance is made possible by the internal organization of silicon. Silicon atoms are arranged together in
a tightly bound structure and by squeezing small quantities of other elements into this structure, two different
types of silicon are created: n-type, which has spare electrons, and p-type, which is missing electrons, leaving
‘holes’ in their place.
 When these two materials are placed side by side inside a solar cell, the n-type silicon’s spare electrons jump
over to fill the gaps in the p-type silicon. This means that the n-type silicon becomes positively charged, and
the p-type silicon is negatively charged, creating an electric field across the cell.
 Because silicon is a semi-conductor, it can act like an insulator, maintaining this imbalance

5. How to make a Solar Phone Charger
 Materials:
2 Mini Solar Panel (3V 20mA each)
1 Tin case (Altoids would work)
1 Solder (3")
1 Small Heat Shrink Tubing (4")
1 Large Heat Shrink Tubing (4")
1 Double Sided Tape (3")
1oz Flux
1 Solder Iron
1 Heat Gun
1 Wire Stripper
1 cell phone charger

6. Step by Step
 Cut wires & tubing: Take the 2 solar power panels and cut all four wires to about 1" in length. Cut 1/4" of
plastic off of the tip of each wire with the wire stripper so copper wires are exposed. This exposed wire is
called a 'lead.' Cut the small heat shrink tubing into four equal pieces (1" each). Slide the small heat shrink
tubing onto both black wires.
 Solder solar panel leads: Using a toothpick, paint leads with flux on a red wire from one solar panel, and a
black wire from the other solar panel. Put those two leads together, and solder using your piece of solder
and the soldering iron.

7. Step by Step Continued
 Heat-shrink tubing: Slide small heat shrink tubing over the leads you just soldered together. Heat the tubing
with heat gun just enough for it to shrink.
 Cut phone charger wire: Cut off the wire from your old charger to about 2.5 feet and strip off 2.5" of outer
plastic from the loose end. Cut 1/4" off of each of the inside wires to make leads. Slide the full length of the
large heat shrink tubing onto this main wire for later use in Step 6

8. Step by Step Continued
 Flux, solder and heat-shrink loose leads: On your main wire, slide a piece of small heat shrink tubing onto
the red wire. Flux all loose leads of main wire as well as the solar panels with the toothpick. Solder red leads
from main wire and solar panels together. Repeat with black wires. Slide heat shrink tubings over these
soldered leads and use heat gun to shrink.
 Test charger: Test the charger by connecting it to a phone under bright light.

9. Step by Step Continued
 Heat-shrink solar panel leads: On your main wire, slide large heat shrink tubing over the two soldered leads
which connect to the solar panels. Use the heat gun to shrink the tubing.
 Tape and close: On the back of the solar panels, cover the two brass rivets with double-sided tape (so
they don't make contact with the Altoids tin.) Tape the two solar panels on the inside lid of the tin. Tuck the
main wire into the case and close. Go somewhere sunny (Florida / California is nice ) and charge it up!

10. Pros and Cons of Solar Panel Charger
 Pros:
• Sun is free and this technology aim towards green improvement lifestyle
• Saves on electricity cost and put money back in our pocket
• They are portable and can be taken on the go to places e.g camps, hiking etc
• Used to charges different devices such as phone, GPS, MP3s, Bluetooths etc.
• Alkaline batteries dies quickly, expensive to replace, and disposal is detrimental to the environment
 Cons:
• It only works during the day, although some panels will generate power in a light cloud cover
• Solar Charger will also take a long time to charge up the devices.
• It is not always compactible with users device and doesn’t charge larger device like
computer.