Understanding Solar Energy

Solar Engineering
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preparation by s.r.kushero
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a centre for application of renewable energy preparation by s.r.kushero email : Care.@care-india.com http://www.care-india.com

Solar Engineering
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Solar power might be a solution
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Solar Engineering BASIC

How much sunshine will I need? How many solar panels you will need based on the
amount of sunshine available daily in your area

Using solar power to produce electricity is not the same
as using solar t produce h t S l th
i l to d heat. Solar thermal principles
l i i l It is presumed that at "peak sun", 1000 W/m² of power
peak sun W/m
reaches the surface of the earth.
are applied to produce hot fluids or air.
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One hour of full sun provides 1000 Wh per m² = 1
Photovoltaic principles are used to produce electricity. A
kWh/m² -representing the solar energy received in one
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solar panel (PV panel) is made of the natural element
element,
silicon, which becomes charged electrically when hour on a cloudless summer day on a one-square meter
subjected to sun light. surface directed towards the sun.

Solar panels are directed at solar south in the northern To put this in some other perspective, the Indian
p
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hemisphere and solar north in the southern hemisphere Department of E
D t t f Energy i di t
indicates th amount of solar
the t f l
(these are slightly different than magnetic compass energy that hits the surface of the earth every +/- hour is
greater than the total amount of energy that the entire
north-south directions) at an angle dictated by the
geographic location and latitude of where they are to be human population requires in a year. Another
perspective is that roughly 100 miles square of solar
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installed.
installed
panels placed in the southwestern U.S. could power the

WHOLE United States .
Typically, the angle of the solar array is set within a
range of between site-latitude-plus 15 degrees and site-
The intensity of the Sun's radiation changes with the
latitude-minus 15 degrees, depending on whether a
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hour of th d
h f the day, ti
time of th year and weather conditions.
f the d th diti
slight winter or summer bias is desirable in the system.
To be able to make calculations in planning a system,
the total amount of solar radiation energy is expressed in
Many solar arrays are placed at an angle equal to the hours of full sunlight per m², or Peak Sun Hours. This
site latitude with no bias for seasonal periods. term, Peak Sun Hours, represents the average amount
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of sun available per day throughout the year.


Solar Engineering Solar Radiation In India
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Solar Radiation : Sunshine across INDIA
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A color coded map of INDIA that displays the

daily average hours of solar radiation
(sunshine). This information will assist you in
calculating the number of solar panels you
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will need for your solar power system. a
short explanation of Watts, Watt Hours, and
Amp Hours
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Solar Engineering BASIC

Electrical charge is consolidated in the PV panel and directed to the output terminals to produce low
voltage (Direct Current) - usually 6 to 24 volts The most common output is intended for nominal 12
volts.
volts, with an effective output usually up to 17 volts.
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A 12 volt nominal output is the reference voltage, but the operating voltage can be 17 volts or higher
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much like your car alternator charges your 12 volt battery at well over 12 volts. So there's a difference
between the reference voltage and the actual operating voltage.
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Solar Engineering
PV system

Q. What is a PV system?
A. PV technology produces electricity directly from electrons freed by the interaction of
sunlight with a solar panel made of semiconductor material. Th power provided i
li ht ith l l d f i d t t i l The id d is
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direct current (DC) electricity. The basic building block is known as a cell. Many cells
put together are known as a module, and many modules assembled together form an
array. A PV system will consist of an array of modules generating DC electricity, an
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inverter, and sometimes battery storage back up with charge controller.

Q. How much electricity will a system p
y y produce?
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A. The amount of power produced will depend upon how large the system is. In Mumbai
the average residential customer purchases 5,500 kilowatt-hours (kWh) per year.
There is enough sunshine falling upon on the average home to produce this and a
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system can be designed to offset all electrical needs. The cost to accomplish a 100%
ff %

system may be prohibitive and sometimes it makes more sense to simply reduce or
'shave' your consumption. Some utilities use tiered rates when they charge for
consumption which means that the more energy you use the higher is the cost per
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kilo-watt-hour. The most economically feasible size is usually between 50% and 75%
of your annual household needs.
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Solar Engineering FREE electricity

At today's prices a single solar panel, rated at 1 Watts sells for about Rs.150-
Rs.250 depending on brand.

If your system uses several of these panels, this would seem to be quite
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expensive.
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The good news is that today's solar panels have a life expectancy of 25 to 30
today s
years or more. And just think, they'll be making FREE electricity that whole time!
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Solar Engineering Manual

The Basics f Solar Power f P d i
Th B i of S l P for Producing El t i it
Electricity

Understanding Parts of a Solar Energy System Overview of the individual components required
to assemble a solar power system and produce free electricity from the sun for energy
p y p y gy
independence.
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1.Solar Panels which generate the electricity,
2.Charge Controller to control battery charging,
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3.the Power Inverter that makes 220 volts AC from the batteries to run your appliances,
4.Storage batteries which store the excess power for use when the sun is weak or not available,
5. AC generators for back-up power.
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Solar Engineering System Overview

For electricity from the sun. You will need one or more
Solar Panels a Charger Controller a Power Inverter
Panels, Controller, Inverter,
and of course, Batteries.
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The first component needed is one or more Solar Panels.
They supply the electricity and charge the batteries. A
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very small system could get away with a couple 80 watt
panels but figure at least 4 to 8 for a small to medium
system..
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A Charge Controller. is needed to prevent overcharging
of the batteries. Proper charging will prevent damage
and increase the life and performance of the batteries.
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The Power Inverter is the heart of the system It makes
system.
220 volts AC from the 12 volts DC stored in the batteries.

It can also charge the batteries if connected to a
generator or the AC line.
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Last are the storage Batteries. They store the electrical
power in the form of a chemical reaction. Without storage
you would only have power when the sun was shining or
the generator was running.
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Solar Engineering Solar Power : Components

A Solar Power energy system can be used by anyone to Charge Controllers
supply all their electrical needs, provide back-up power, This device is necessary to protect the batteries from over
or even just as a supplement to the normal electrical grid charging and supply them with the proper amount of
connection to a utility company. It is ideal for remote energy to promote long battery life.
locations where power is unavailable or too expensive to
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hook-up to. Power Inverters
The power inverter converts your storage battery power
Solar Panels into the 220 volts AC that runs your appliances. It is the
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The S Solar Panels tutorial will give you a simple heart of your solar energy system Unless you only run 12
system.
explanation of this most basic electric power generator volt DC appliances you will need a power inverter to supply
for solar energy systems. Fixed, Adjustable, and your AC.
Tracking type mounting systems are also covered.
Getting power from the sun's energy is not only Free, but
gp gy y , Storage Batteries
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it's Fun to setup a solar energy system and be your own Without Storage Batteries to store energy you would only
utility company have power when the sun was shining or the generator as
running. Here we discuss 4 major categories of batteries
for solar power systems. The batteries in your system are
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very important. The care & feeding section of this tutorial is
a must read to ensure long battery life and good

performance.

AC Generators
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Even the largest Solar Energy System would not have
enough power for many consecutive days of no sun. The
AC Generator tutorial will tell you what size generator you'll
need
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Solar Engineering
Solar Panels

Solar panels generate free power from the sun by converting sunlight to electricity with no moving
parts, zero emissions, and no maintenance. The solar panel, the first component of a electric solar
e e gy sys e , s co ec o o
energy system, is a collection of individual silicon cells that generate electricity from sunlight. The
d dua s co ce s a ge e a e e ec c y o su g e
photons (light particles) produce an electrical current as they strike the surface of the thin silicon
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wafers.
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A single solar cell produces only about 1/2 ( 5) of a volt However a typical 12 volt panel about 25
(.5) volt. However,
inches by 54 inches will contain 36 cells wired in series to produce about 17 volts peak output.

If the solar panel can be configured for 24 volt output, there will be 72 cells so the two 12 volt groups
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of 36 each can be wired in series, usually with a jumper, allowing the solar panel to output 24 volts.
When under load (charging batteries for example), this voltage drops to 12 to 14 volts (for a 12 volt
configuration) resulting in 75 to 100 watts for a panel of this size.
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Multiple solar panels can be wired in parallel to increase current capacity (more power) and wired in

series to increase voltage for 24, 48, or even higher voltage systems. The advantage of using a higher
voltage output at the solar panels is that smaller wire sizes can be used to transfer the electric power
from the solar panel array to the charge controller & batteries Since copper has gone up considerably
batteries.
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in the last few years, purchasing large copper wiring and cables is quite expensive. (that's why
pennies are made of mostly zinc today).
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Solar Engineering Solar Panels

An
A eco-friendly electric generator. S l
f i dl l ti t Solar panelsl
generate free power from the sun by converting
sunlight to electricity with no moving parts, zero
emissions, and no maintenance. The solar panel,
the first component of a electric solar energy
system, is a collection of individual silicon cells that
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generate electricity from sunlight.
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The photons (light particles) produce an electrical
current as they strike the surface of the thin silicon
wafers. A single solar cell produces only about 1/2
(.5) of a volt.
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However, a typical 12 volt panel about 25 inches by
54 inches will contain 36 cells wired in series to Multiple solar panels can be wired in parallel to
produce about 17 volts peak output. increase current capacity (more power) and wired
in series to increase voltage for 24, 48, or even
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higher lt
hi h voltage systems.
t
If the solar panel can be configured for 24 volt

The advantage of using a higher voltage output at
output, there will be 72 cells so the two 12 volt the solar panels is that smaller wire sizes can be
groups of 36 each can be wired in series, usually used to transfer the electric power from the solar
with a jumper allowing the solar panel to output 24
jumper,
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panel array to the charge controller & batteries
batteries.
volts. When under load (charging batteries for Since copper has gone up considerably in the last
example), this voltage drops to 12 to 14 volts (for a few years, purchasing large copper wiring and
12 volt configuration) resulting in 75 to 100 watts for cables is quite expensive. (that's why pennies are
a panel of this size. made of mostly zinc
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Solar Engineering Solar Panels : TYPES

Amorphous solar panels : These are not really
Monocrystalline solar panels : The most
crystals, but a thin layer of silicon deposited on a
efficient and expensive solar panels are base material such as metal or glass to create
made with Monocrystalline cells These
cells. the solar panel. These Amorphous solar panels
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solar cells use very pure silicon and are much cheaper, but their energy efficiency is
involve a complicated crystal growth also much less so more square footage is
process. Long silicon rods are produced
g required to produce the same amount of power
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which are cut into slices of .2 to .4 mm as the Monocrystalline or Polycrystalline type of
solar panel. Amorphous solar panels can even
thick discs or wafers which are then
be made into long sheets of roofing material to
processed into individual cells that are cover large areas of a south facing roof surface.
wired together in the solar panel
panel.
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Polycrystalline solar panels : Often called
Multi-crystalline, solar panels made with
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Polycrystalline cells are a little less expensive &

slightly less efficient than Monocrystalline cells
because the cells are not grown in single crystals
but in a large block of many crystals. This is what
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gives them that striking shattered glass
appearance. Like Monocrystalline cells, they are
also then sliced into wafers to produce the
individual cells that make up the solar panel.
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Solar Engineering Solar Panels : Wattage

The output of a solar panel is usually stated Since the intensity of sunlight contacting
in watts, and the wattage is determined by the solar panel varies throughout the day,
multiplying the rated voltage by the rated
u p y g e a ed o age e a ed we use the term "peak sun hours“ as a
e e e pea su ou s
amperage. method to smooth out the variations into a
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daily average
The formula for wattage is VOLTS times
Early morning and late-in-the-day sunlight
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AMPS equals WATTS
WATTS.
produces less power than the mid-day sun.

So for example, a 12 volt 60 watt solar panel Naturally, cloudy days will produce less
measuring about 20 X 44 inches has a rated p
power than bright sunny days as well.
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voltage of 17.1 and a rated 3.5 amperage.
When planning a system your
VxA=W geographical area is rated in average peak
sun hours per day based on yearly sun
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17.1
17 1 volts times 3 5 amps equals 60 watts
3.5
data.

If an average of 6 hours of peak sun per day Average peak sun hours for various
is available in an area, then the above solar g g p
geographical areas is listed in the above
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panel can produce an average 360 watt section.
hours of power per day; 60w times 6 hrs. =
360 watt-hours.
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Solar Engineering Solar Panels Wiring

Series
S i
Solar panels can be wired in series or in parallel to increase
voltage or amperage respectively, and they can be wired
both in series and in parallel to increase both volts and
amps.
amps
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Series wiring refers to connecting the positive terminal of +
one panel to the negative terminal of another. The resulting -
outer positive and negative terminals will produce voltage
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the sum of the two panels, but the amperage stays the same Parallel
as one panel. So two 12 volt/3.5 amp panels wired in series
produces 24 volts at 3.5 amps. Four of these wired in series
would produce 48 volts at 3.5 amps.
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Parallel wiring refers to connecting positive terminals to
positive terminals and negative to negative. The result is that +
voltage stays the same, but amperage becomes the sum of
-
the number of panels. So two 12 volt/3.5 amp panels wired
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in parallel would produce 12 volts at 7 amps. Four panels Series/parallel
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would produce 12 volts at 14 amps.

Series/parallel wiring refers to doing both of the above -
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increasing volts and amps t achieve th d i d voltage as
i i lt d to hi the desired lt
in 24 or 48 volt systems. The following diagram reflects this.
In addition, the four panels below can then be wired in
parallel to another four and so on to make a larger array.
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Solar Engineering Solar Installation : Location

Where a building is at a considerable distance from the public electricity supply (or grid)
- in remote or mountainous areas – PV may be the preferred possibility for generating
electricity, or PV may be used together with wind, diesel generators and/or
hydroelectric power In such off-grid circumstances batteries are usually used
power. off grid
to store the electric power.
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In locations near the grid however feeding the grid using PV panels is more practical
grid, however, practical,
and leads to optimum use of the investment in the photovoltaic system. This requires

both regulatory and commercial preparation, including net-metering and feed-in
agreements. To provide for possible power failure, some grid tied systems are set up to
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allow local use disconnected from the grid. Most photovoltaics are grid connected. In
the event the grid fails, the local system must not feed the grid to prevent the possible
creation of dangerous islanding.
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Solar Engineering Solar Panels : Placement

Shading Shadows
Sh di & Sh d Temperature & Wi d l di considerations
T t Wind loading id ti

When deciding on a location for your solar As previously discussed, you want to mount
panels, make sure no shadows will fall on the solar panels in a sunny and non-shaded location
p y
solar panel array during peak sunlight hours to get maximum sun. But, heat build-up is also a
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(say, 9am to 4pm). Not only will shading of the problem. Because the efficiency of solar panels
solar panels significantly reduce their output, but decreases as temperature increases, the solar
also could cause damage. Some solar panel p
panel mounting system should allow for spacing
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manufacturers advertise panels that can around the individual solar panels for air
withstand shading but they use internal diodes circulation. The idea is to allow air cooling in the
which in themselves reduce the power hot sun to reduce the temperature of the solar
somewhat. I recommend simply choosing a good p
panels. Another consideration is wind loading. By
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location to start with, even if it means cutting allowing air to flow around the solar panels, not
down a few trees or otherwise removing only will they remain cooler,
obstacles.
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Solar Engineering Efficiency Losses

In all systems there are losses due to such things as voltage losses as the electricity is
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carried across the wires, batteries and inverters not being 100 percent efficient, and other
factors. These efficiency losses vary from component to component, and from system to
system and can be as high as 25 percent.
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Solar Engineering Solar Panels : Mountings

Types of Solar Panel Array Mountings

: Fixed, Adjustable, & Tracking Fixed solar panel
mounts : If you use th most simple and l
t the t i l d least expensive
t i
type of solar panel mounting system, it will be completely
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stationary. The solar panels should always face the
equator. (due south in the northern hemisphere). Don't
forget that true south varies from magnetic south. This
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can make a huge difference. For example, true south in
eastern Washington state is 161 on a compass instead
of 180. The angle of inclination (tilt) in degrees should be
set to about your latitude. Slightly more than your latitude
will favor the winter sun and slightly less will favor the
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summer sun. (for a seasonal cabin for example).

Adjustable solar panel mounts : The angle of inclination
( )
(tilt) of an adjustable solar panel mount can be changed
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2 or more times during the year to account for the lower

angle of the sun in winter as the earth orbits the sun
causing seasonal change. A good rule of thumb is
latitude + 15 degrees in the winter and latitude – 15
degrees in the summer This will increase overall solar
summer.
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panel output by approximately 25%. I adjust my solar
panel array 4 times per year. (Shown here in its summer
position). An easy approach that works pretty good is to
set the tilt for the winter position in about mid October
and b k t summer position i mid.
d back to iti in id
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Solar Engineering Charge Controller

A charge controller monitors the battery's state
battery s state- Many charge controllers also offer Low Voltage
of-charge to insure that when the battery needs Disconnect (LVD) and Battery Temperature
charge-current it gets it, and also insures the Compensation (BTC) as an optional feature. The
battery isn't over-charged. Connecting a solar LVD feature permits connecting loads to the LVD
panel to a battery without a regulator seriously terminals which are then voltage sensitive. If the
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risks damaging the battery and potentially battery voltage drops too far the loads are
causing a safety concern.
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disconnected - preventing
potential damage to both the battery and the
Charge controllers (or often called charge loads. BTC adjusts the charge rate based on the
regulator) are rated based on the amount of
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temperature of the battery since batteries are
amperage they can process from a solar array. If sensitive to
a controller is rated at 20 amps it means that you temperature variations above and below about
can connect up to 20 amps of solar panel output 75 F degrees.
current to this one controller. The most advanced
charge controllers utilize a charging principal
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referred to as Pulse-Width-Modulation (PWM) - To Load Switched
which insures the most efficient battery charging
and extends the life of the battery.
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Even more advanced controllers also include
Maximum Power Point Tracking (MPPT) which

maximizes the amount of current going into the
battery from the solar array by lowering the To Load Always On
panel's output voltage, which increases the
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charging amps to the battery - because if a panel From Solar Panel
can produce 60 watts with 17.2 volts and 3.5
amps, then if the voltage is lowered to say 14
volts then the amperage increases to 4.28 (14v
X 4.28 amps = 60 watts) resulting in a 19%
increase in charging amps for this example
example.
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Solar Engineering Connections

After you connect the Solar Panels to the input Connecting the Batteries
terminals of the Charge Controller using the
above chart, you can use the same size wire to The batteries are last. They will also require very
connect the Charge Controller output to the large cables like the large battery cables in cars.
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batteries since these wires will carry no more The full current to the loads and also the full
current than the solar panel wires and will charging current flow thru the entire battery
probably be located pretty close to the batteries bank. Connect all the batteries with large high
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anyway. quality cables. Check out the Battery Wiring
Diagrams tutorial for examples of Series and
Connecting the Power Inverter Parallel wiring techniques that allow the use of
battery voltages of 2, 4, 6, or 12 volts. Our new
The Power Inverter is next Both the Power
next.
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Battery Bank Designer tool will show you how to
Inverter and the Batteries require the largest
connect the batteries for these various voltage
wires in the system. During operation, the AC
produced by the Power Inverter draws
considerable amps from the batteries Not only
batteries.
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are very large wires required, but they should not

exceed 6 feet in length to reach the batteries.
These wires are like the large battery cables in
cars.
cars Use the largest size possible An AC
possible.
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appliance drawing 10 amps (like a microwave or
vacuum cleaner) will require 100 amps at 12
volts DC. Even large cables will get warm. Don't
skimp here
here.
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Solar Engineering Wire & Cables

To prevent dangerous overheating or inefficient Battery Wiring Diagrams
transfer of power, the wires and cables in a solar Learn how to use series and parallel wiring
power system must be correctly sized. A
convenient chart to determine wire size based on techniques to obtain exactly the power and
solar panel power output and the distance voltage you want using 2, 4, 6,or 12 volt
between the solar panels and the batteries. For batteries.
batteries Series wiring parallel wiring and
wiring,
using series/parallel combinations show you
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safety and good performance of your solar
power system you will have to use the how to build your battery bank into any
appropriate size wires when connecting the
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components of your system
system.

Meters & Monitors
This tutorial explains the importance of
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monitoring your solar energy system With the
system.
included voltage chart, you can easily determine
the basic level of charge on your batteries using
just a simple voltmeter. Taking proper care of
y
your batteries will ensure good system
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performance

Power Requirements
This tutorial is a little more advanced but
advanced,
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explains more about voltage, current, power, and
Ohm's Law. Find out about the relationship
between AC amps and DC amps. The
importance of energy conservation for a solar
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power system is also covered.


Solar Engineering Battery

During planning, all of these factors are looked at, and The Deep Cycle batteries used are designed to be
discharged and then re-charged hundreds or thousands
the one requiring the largest capacity will dictate the of times. These batteries are rated in Amp Hours (ah) -
battery size. One of the biggest mistakes made by those usually at 20 hours and 100 hours. Simply stated, amp
just starting out is not understanding the relationship hours refers to the amount of current - in amps - which
between amps and amp-hour requirements of 120 volt can be supplied by the battery over the period of hours.
AC items versus the effects on their DC low voltage
batteries. For example, say you have a 24 volt nominal
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system and an inverter powering a load of 3 amps, For example, a 350ah battery could supply 17.5
120VAC, which has a duty cycle of 4 hours per day. You continuous amps over 20 hours or 35 continuous amps
would have a 12 amp hour load (3A X 4 hrs=12 ah). for 10 hours. To quickly express the total watts
However, in order to determine the true drain on your potentially available in a 6 volt 360ah battery; 360ah
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batteries you have to divide your nominal battery voltage times the nominal 6 volts equals 2160 watts or 2 16kWh
2.16kWh
(24v) into the voltage of the load (120v), which is 5, and (kilowatt-hours).
then multiply this times your
Like solar panels, batteries are wired in series and/or
120vac amp hours (5 x 12 ah). So in this case the parallel to increase voltage to the desired level and
calculation would be 60 amp hours drained from your
p y increase amp hours.
p
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batteries - not the 12 ah. Another simple way is to take
the total watt-hours of your 120VAC device and divide The battery should have sufficient amp hour capacity to
by nominal system voltage. supply needed power during the longest expected
period "no sun" or extremely cloudy conditions. A lead-
Using the above example; 3 amps x 120 volts x 4 hours acid battery should be sized at least 20% larger than
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= 1440 watt hours divided by 24 DC volts = 60 amp
watt-hours this amount If there is a source of back up power such
amount. back-up power,
hours. Lead-acid batteries are the most common in PV as a standby generator along with a battery charger, the

systems because their initial cost is lower and because battery bank does not have to be sized for worst case
they are readily available nearly everywhere in the world. weather conditions. The size of the battery bank
There are many different sizes and designs of lead-acid required will depend on the storage capacity required,
batteries, but the most important designation is that they the maximum discharge rate, the maximum charge rate,
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are d deep cycle b tt i
l batteries. L d id b tt i
Lead-acid batteries are and th minimum t
d the i i temperature at which th b tt i will
t t hi h the batteries ill
available in both wet-cell (requires maintenance) and be used.
sealed no-maintenance versions. AGM and Gel-cell
deep-cycle batteries are also popular because they are
maintenance free and they last a lot longer.
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Solar Engineering Battery Wiring Diagrams
Wiring up your battery bank. Use 2, 4, 6, or 12
volt b tt i
lt batteries t b ild a system voltage of 12
to build t lt f 12,
24, or 48 volts using series and parallel wiring
with just 4 clicks. Battery bank capacities from
300 Amp/Hours to over 4000 Amp/Hours

•AWG (American Wire Gauge)
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Based on the distance to your solar panel array
& the amount of amperage your panels put out.
Configurations are possible for Amp/Hour
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capacities from as little as 300 Amp/Hours to
over 4000.

To use the Designer, follow these 4 simple
steps : Click 2, 4, 6, or 12 volt batteries to build
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your Battery
1.Battery Bank.
2. Select the closest Amp/Hour rating for 1
Battery.
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3.
3 Choose your System Battery Bank voltage voltage.
(your inverter input voltage)

4. Select the size of the Battery Bank capacity
in Amp/Hours.
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To determine the Amp/Hour capacity you will
need, use System Sizing Estimator which will
calculate the Amp/Hour capacity of your battery
bank and also the number of solar panels
required.
required
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Solar Engineering Battery Bank

Configurations are possible for AmpHour
capacities from as little as 300 AmpHours to over
4000.
4000 To use the Designer follow these 4 simple
Designer,
steps :
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1.Battery Bank. Batteries come in various
individual sizes. They can be connected to
DE

increase th system voltage.
i the t lt
2. Select the closest Amp/Hour rating for 1
battery.
To determine the total Amp/Hour capacity of
p p y
OLAR ENER

your battery bank you must use the rating for 1
battery.
3. Choose your System Battery Bank voltage.
(your inverter input voltage) The System Voltage
ANDING SO

is the combined voltage of the entire battery

bank.
The Solar Panels, the Charge Controller, and the
“UNDERSTA

Inverter will all use this voltage
voltage.
4. Select the size of the Battery Bank capacity in
Amp/Hours.This is the total capacity required to
run your solar energy system.
“



Storage Batteries : the fuel tank of your solar power
Industrial strength : Flooded, Gel, and AGM sealed
system
batteries
Without batteries to store energy you would only have power when
the sun was shining or the generator was running. This tutorial The next 3 types are the heavier industrial type batteries.
describes the 4 basic types of batteries & provides some good tips They are all also considered Deep Cycle and are usually Lead
on the care & feeding of your batteries tomaximize their performance Acid types with much thicker internal plates that can withstand
and life. many deep discharge cycles. These next 3 are all designed for
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alternative energy systems.
1) RV / Marine / Golf Cart : RV or Marine type deep cycle batteries 2) Flooded types : These are Lead acid batteries that have caps to add
are basically for boats & campers and are suitable for only very water. Many manufacturers make these types for Solar Energy use.
small systems. They can be used but do not really have the capacity Trojan, Surrette, and Deka are probably the most well known. They are
DE

for continous service with many charge/discharge cycles for many reasonably priced and work well f many years. All fl d d b tt i
bl i d d k ll for flooded batteries
years. Regular or Car type batteries should not be used at all release gas when charged and should not be used indoors. If installed
because they cannot be discharged very much without internal in an enclosure, a venting system should be used to vent out the gases
damage. A very popular battery for small systems is the Golf Cart which can be explosive.
battery.
3) Gel : Not to be confused with maintenance free batteries, sealed gel
OLAR ENER

They are somewhat more expensive th
Th h t i than d
deep cycle recreational
l ti l batteries have no vents and will not release gas during the charging
batteries but are probably the least expensive choice for a small process like flooded batteries do. Venting is therefore not required and
system on a budget. they can be used indoors. This is a big advantage because it allows the
batteries to maintain a more constant temperature and perform better.

4) AGM : Absorbed Glass Mat batteries are in my opinion the best
) G bso bed G ass at batte es a e y op o t e
ANDING SO

available for Solar Power use. A woven glass mat is used between the
plates to hold the electrolyte. They are leak/spill proof, do not out gas

when charging, and have superior performance. They have all the
advantages of the sealed gel types and are higher quality, maintain
voltage better, self discharge slower, and last longer. The Sun Xtender
series by Concorde Battery is an excellent example of AGM batteries.
“UNDERSTA

They are more expensive, but you usually get what you pay for. You
will find this type of battery used in airplanes, hospitals, and remote
telephone/cell tower installations.
“



Care and Feeding
As a technician, I used to say that if you are not comfortable,
then neither is your equipment. I was mostly referring to
temperature and humidity In fact battery capacity ratings are
humidity.
usually specified at 77 degrees F. As batteries get colder
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their voltage drops and performance suffers.
DE

This is
Thi i one major reason I prefer AGM b tt i
j f batteries
because they can be stored indoors where the temperatures
vary less. Another important thing to consider is how deeply
you discharge your batteries. This is known as the DOD
OLAR ENER

(depth of discharge). In other words, how low you let the
voltage drop before the next charge cycle. Most battery
ratings talk about 50% or so, but they will last longer if you
keep them as charged as possible. I like the 70% range.
ANDING SO

Lead acid batteries like to be fully charged. They will last
much longer if you do not discharge them too deeply. This is
known as shallow cycling and greatly extends their life.
“UNDERSTA

However, they can withstand discharges down to 20% or so,
but I wouldn't do it too often
“


Solar Engineering Wire & Cables

To connect the components of a Solar
Energy System, you will need to use correct
wire sizes to ensure low loss of energy and
to prevent overheating and possible damage
or even fire Below is a chart showing the
fire.
equired wire size for wire lengths to connect
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the solar panels to the Charge Controller.
DE

Use these numbers for a 12 volt system to
achieve a 3% or less voltage drop.

The top row represents the Wire gauge size,
the left column the number of amps the solar
OLAR ENER

panels are rated at, and the grid cells show
the distances in feet between the Solar
Panels and the Charge Controller.
ANDING SO

This chart shows wire distances for a 3%

voltage drop or less. NOTE : This chart is an approximate
distance reference and is a little
conservative. For a much more accurate
“UNDERSTA

These distances are calc lated for a 12 volt
calculated olt
system. Multiply distances by 2 for a 24 volt wire sizing, use our new Wire Size
system. Multiply distances by 4 for a 48 volt Calculator tool. It can calculate wire size
system. using 3%, 4%, or 5% losses plus you can
select 12, 24, or 48 volt systems
, , y
“

.

Understanding Solar Energy

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