Building a solar generator
Introduction
•Hi my name is David Galietti, I
have been a resident of Las Vegas
for 30 years. I have spent the last 6
years at the Las Vegas Valley water
district in facilities operations
division. I have been interested in
sustainability and GEEN technology
since the Water District became
involved with the Springs Preserve.
I currently hold the L.E.E.D Green
Associate credential.
Topic intro
•I would like to talk with you today
about building a solar generator
and how it works.
•Tell you where I purchased my
components and what they cost.
•Then open up the class for
dialogue.
Basics of Solar panel
operation
•A solar panel converts sunlight into
usable electricity…..please refer to the
first hand out.
•The sun's rays produce Photons
which are radiated at the earth. When
Photons hit a solar panel they cause
the positive and negatively charged
electrons to be “knocked “ loose in
the form of current. Each small cell in
a solar panel can produce .5
volts……so it takes 24 solar cells wired
together to produce a 12 volt panel!
This is what you see when you look at
a solar panel. (see panel)
Power production
•A 12 volt Solar panel can produce
more or less voltage depending on
how much sun hits it (photons).
•Power can be between 3 and 30
volts!
•This is why we need to throttle the
output of the solar panel down to a
usable voltage of 12 volts using a
charge controller (see page 2 of
handout).
•We will discuss this a little later.
Optimum position of
solar panel
•Since the angle and position of
your solar panel is important to the
maximum amount of sun (photons)
smacking into it.
•You must try and position your
panel so that the sun hits it straight
on. A good way of doing this
is….place a block of wood directly
on your solar panel…..then adjust
the angle/tilt until the shadow goes
away.
•Panel needs to point true south.
Types of solar panels
•There are several types of solar
panels available on the market.
•Amorphous (cheapest and least
efficient)
•Polycrystalline (mid-range in price.
Medium efficiency
•Monochrystaline. (most expensive.
Highest rating.
Hooking up your
components
•To get a usable voltage out of your panels we must hook
them up a certain way.
•Always observe polarity. Positive to positive and
negative to negative.
•As I mentioned earlier we need to harness the varying
voltage from the solar panel into a usable 12 volts.
•The positive and negative leads from the solar panel go
to the solar panel input of the charge controller.
•The battery positive and negative leads from the
controller go to the battery (see diagram)
•The charge controller is vitally important in that it keeps
the battery fully charged and automatically disconnects
power from the panels when full and applies powers
when battery is discharging.
•The charge controller must be rated as a minimum the
same wattage as all your solar panels combined.
•Some charge controllers have a meter to read
voltages/amp/usage etc.
Inverters
•An inverter is needed when you wish
to connect a 120 volt a/c device to
your solar system.
•It converts 12 volts d/c to 120 volts a/c.
•The inverter must be rated for the
wattage of the devices that you want
to run.
•(see last page for calculation sheet)
•Inverters must be hooked to the
battery bank with a heavy gauge wire
similar to the size of your battery
cables on your car. Too small and not
enough power from your battery will
flow to the inverter and cause it to
turn off.
Battery
•Batteries that you want to use in
your solar system must be deep
cycle type…not normal car batteries
( they will work in emergency)
•Deep cycle batteries are designed
to be heavily discharged and
recharged with minimal wear and
tear on them.
•Car batteries are meant for a quick
heavy current draw and minimal
charge and re-charging.
Ex: battery capacities
•I have two batteries hooked in
parallel.
•They have approx. 200 amp hrs total.
•Using the formula on the last page….
•200 X 12 volts = 2400 watt hours
available.
•Purchased at Wal-Mart for around
$80 each.
•If you have an old battery sitting in
your garage bring it with you and
get a $15 credit.
•Look for the RV batteries (they are
deep cycle)
Example of my solar panels
capacities
•My solar panels hooked together equal
about 250 watts.
•So using our calculations….
•250 watts X 7 hours of sun in winter
=1487 watt hours of solar power.
•250 watts X 12 hours of sun summer
=2550 watts of solar power.
•Purchased 45 watt system at harbor
freight tools for $ 135 (amorphous type)
•Purchased 2 each 100 watt
monochrystaline panels from eBay…..$
150.. Each.
Example of my Charge
controller
•500 watt charge controller
•Leaves me room for expansion.
•Purchased on e-bay for $35
•Meter on device for reading
charge voltage, battery voltage etc.
Example of solar
aquaponics pump
•390 gallon per hour submersible
water pump
•21 watt (3.3 amps)
•Purchased on eBay $35.00
•21 watts X 24 hours run time=504
watts per day.
Accessories
•Heavy gauge Wire purchased at
home depot or Lowes. (for inverter)
•Wal-Mart has a good selection of
12 volt stuff in their
camping/electrical section.
•They have cigarette lighter
adapters…male and female.
•Inline fuse connections.
•Battery
cables/terminals…AutoZone
Read voltages/check connections
Open for discussion