Will Solar Work
for my Home?
Q. What are the
advantages of solar generated electricity?
A. Solar electricity
generates energy without polluting the environment: no emissions,
no noise and no waste. Solar panels require very little
maintenance. The amount of electricity produced by a solar system
varies depending on the amount of sunlight available yet it
produces long-term, reliable electricity.
A solar system can be installed almost anywhere under direct
sunlight, making it more versatile than other renewable energy
sources. Sun Earth PV systems have been installed from small
household rooftops to large utility scale power stations around
Q. What is Vertical Integrated Production?
A. A PV module manufacturer achieves vertical integrated
production when they oversee the entire production process of
solar modules. It starts from silicon mining, ingot production,
wafer cutting, to manufacturing solar cells and assembling
modules. With this vertical integrated progress, the manufacturer
controls the quality of every single aspect of the manufacturing
process. Alpha manufactures solar modules using a vertical
integrated production. This is how Alpha guarantees the highest
quality of solar modules with a 25-year warranty.
Q. Will a PV system work in cold weather?
A. PV systems also work well in cold weather. In fact, PV
generates electricity from light, not heat. It will perform even
better in cooler areas than in a hot area with the same amount of
sunlight. Alpha’s 500kW system in Italy has a very good
performance with temperatures under zero degrees Celsius.
Q. How long will PV modules generate electricity?
A. The life cycle of a PV module depends on the quality of the
solar cell. Top quality modules, such as the Sun Earth solar
module with its own quality control in cell production, are
designed to generate electricity for at least 30 years. With
Alpha’s 20 years warranty, solar modules are warranted to produce
90% for first 10 years and 80% for the next 10 years of their
original minimum power rating. In fact, most of the Alpha modules
installed working perfectly , producing over 95% of their original
Q. How to choose a PV module?
A. There are several important factors to consider when choosing a
PV module. The first is verifying the quality of the module
through their certifications. In Australia, the International
Electro technical Commission’s Standards (IEC) is the authority
for solar module certification. Solar modules must also comply
with IEC61215 and IEC61730 (Class A) in order to apply for
Australian government rebates. There are some other safety
standards widely used around the world, like Underwriters’
Laboratories (UL) and CE. The next step is check construction of
the module. It should feel solid when lifted. Check that the
junction box is firmly attached. Pay attention to the length of
the warranty and make sure the company who manufactured it has a
Investigate whether the solar module company has total operational
control of their products. Do they manufacture the module only
with outsourcing the solar cell? Do they have an established
business that will be operating into the foreseeable future? Have
their products proven reliable in many years of operation?
Finally, what are the price points of the module and how do they
Q. What is the difference between mono-crystalline and
A. In general, the solar cell efficiency of mono-crystalline is
slightly higher than the poly-crystalline. Alpha tests every
single cell in our manufacturing process to ensure the power
generated by mono-crystalline which is very high efficient modules
is as indicated on the label. That means the power performance of
a 200 Watt mono-crystalline module is the same as a 200Watt
Q. What is the warranty on the solar modules?
A. The warranty on Alpha Solar modules first 10 years 90% power
guarantee, and 25 years 80% power guarantee, and 5 years materials
and workmanship warranty.
Q. How does a solar cell work?
A. Solar cells convert light into electricity. To convert sunlight
into electricity light must be absorbed in the solar cell.
Collecting sunlight to make electric current at the junction of
two substances, photovoltaic (or PV) technology is the most
harmless method of power generation. PV is a direct current (DC)
generator powered by the sun. When light photons hit the surface
of a solar cell, electrons roam free in the silicon crystal
structure forcing them through an external circuit (battery or
direct DC load), and then returning them to the other side of the
solar cell where the cycle recurs. The voltage output from a
single solar cell is about 0.5V with an output that is directly
proportional to cell's surface area (approximately 7A for a 6 inch
square for a typical solar cell).30-36 cells are wired in series
(+ to -) in each solar module. This produces a solar module with a
12V nominal output (~17V at peak power) that can then be wired in
with other solar modules.
Once a light generated carrier is collected, it can be either
extracted from the device to give a current, or it can remain in
the device and gives rise to a voltage. Generally, some of the
light generated carriers are used to give a current, while others
are used to create voltage. The combination of a current and
voltage give rise to a power output from the solar cell.
Q. Is PV economical?
A. PV becomes increasingly economical as the size of the load
becomes smaller and distant from grid power. If grid power is not
available and the required energy is that of a typical household
load, a PV system is usually the lowest cost option. For consumer
appliances, PV can be up to 100 times cheaper than battery power.
For cases where reliable grid power is readily available, PV is
usually not the lowest cost option, unless environmental impacts
are factored in. Even in these cases, the economic viability of PV
PV is not technically or economically suited to large base-load
power for utilities, but may be suited to power production for
individual houses in locations with high peak electricity prices
occurring during the day. For grid-connected applications, the
costing of a PV system for a particular location and application
needs to be considered on a region-by-region basis.
Q. What are the advantages and disadvantages of PV?
A. In a number of applications, PV systems have several
important technical advantages that make them the best choice for
electricity generation. PV panels are extremely reliable and
require low maintenance, they can operate for long periods and
they are suitable for both large and small loads. These
characteristics make PV an ideal choice for both remote power and
remote residential electricity applications. For such remote
applications, a PV-based system is usually the lowest cost choice.
There are a number of other advantages, such as the distributed
nature of PV power production and the low lead times to
installation, which may be beneficial in grid connected
installations. PV electricity generation is also environmentally
friendly, with the lowest environmental impact of any of the
electricity generating technologies.
The disadvantage of PV is its high cost compared to many other
large-scale electricity generating sources. This applies to the
use of PV for applications that are already tied to the
electricity grid. Another concern is that the power density of
sunlight is relatively low. This means PV tends to be less suited
to applications that are physically small compared to the amount
of power they require. Although solar cars, solar trains, solar
planes and solar boats have all been made and used, in general
these applications are difficult for PV or other solar-based
Q. What are the components of a photovoltaic system?
A. The possible components of a PV system are a power conditioning
sub-system, a storage mechanism, and other general components
called “balance of system” (BOS) components. The power
conditioning sub-system serves two functions.
One component of a power sub-system is often called a charge
controller, which ensures that a battery in the system is charged
from the pv array. The second component is an inverter, which
converts the low DC voltage of the pv system into the same type of
power (higher voltage AC) produced by a utility company Depending
on the type of application, the inverter may also serve several
other functions, such as battery charging or may disconnect the
system from the utility when necessary. Another possible component
of a PV system is the storage system. When included, this is
usually battery storage, consisting of lead-acid batteries
modified from those in cars in order to allow large amounts of
energy to be drawn from them. Other system components are usually
grouped under the term BOS and include the wiring of the array,
the array mounting and battery housing.
The components of a PV system depend on what the system will be
used to power. If the load is DC, then the inverter (which
converts AC to DC) is not needed. Similarly, if the system is
connected to the utility grid, the storage (and hence a charge
controller) is not needed, while the inverter is.
Residential Solar FAQ
Q. How Does a Solar PV System Work?
A. Solar PV systems consist of modular panels made of silicon,
which transform light energy into electricity. An inverter
converts DC (direct current) generated by the panels into AC
(alternating current), supplying power to your home or to utility.
Q. What Size System Do I Need?
A. Solar PV Installation Inc. tailors PV systems to the unique
circumstances of each home or business. A detailed site survey is
conducted to determine the appropriate system size. We provide
these services at no cost.
Q. How Much Does A PV System Cost?
A. System cost depends on size, materials and labor. Most
Solar PV Installation Inc. systems pay for themselves within 7 to
9 years. Every PV system is sized and designed to optimize
performance and aesthetics.
Q. The 3 Main
Types of PV Cells, which is best?
A. Monocrystalline: made from thin slices cut from a single
crystal of silicon.
Polycrystalline: made from thin slices cut from a block of silicon
Thin Film: made from a very thin layer of a semiconductor
deposited on a glass or metal base.
Monocrystaline PV solar is the most efficient solar sold around
Q. Is there enough sunlight to make a contribution to the
world’s energy needs?
A. Yes. The earth receives more energy from the sun in just
one hour than the world uses in a whole year.
Q: I want to use solar panels at home to lower my electricity
bills. I don't know my daily electricity consumption. Where should
A: You can find your monthly consumption from your
electricity bill. Due to the seasonal usage, it is better to see
the bills in different seasons and find the average usage per
month. Then divide it by 30 in order to get your daily usage.
Q: I know my daily electricity consumption but I don't know
which system to choose?
A: There are three types of photovoltaic system. Grid-Tie
Systems, Grid-tie Systems with Battery Backup and Off-Grid
Systems. For the details check our educational page.
Q: What factors should I take into account in order to choose
the solar panel?
A: Usually the panels are selected by their power and their
Q: The maximum panel I found on the internet was 250 watts
while I need 1kW (1000 Watts) power. How do I know the number of
A: 1000W divided by 250W is 4 panels, but in reality you
should overshoot your power requirements because the 250W rating
is the maximum power, not the power for normal usage.
Q: The solar panels produce direct current (DC) but I want to
use it for my house lighting and the lights need AC current. What
should I do?
A: You need an inverter to get the same type of electricity
as the utility.
Q: What is an inverter?
A: An inverter is a device which converts the Direct Current
(DC) into Alternative Current (AC). If you want a photovoltaic
system for your house or office, you need an inverter. For more
information about the inverter, please visit the inverter page.
Q: Some inverters have 110V/60Hz output and some 220/50Hz.
How can I make sure that I have chosen the right one?
A: In fact the voltage and frequency varies in different
regions. For example, most of the countries in American continent
use 110 Volt/60Hz electricity while in Europe and Asia the Voltage
and frequency is 220V/50Hz and when you want to choose an
inverter, you have to make sure the its output is compatible to
your region standard.
Q: What is the difference between panels in parallel and
panels in series?
A: Panels in parallel add their current ratings while their
voltage remains the same. Series connections add the voltage while
keeping the current the same (the exact opposite of parallel
Q: At the back of the panel, I see the Voc (open circuit
voltage) and the Isc (short circuit current), what is this
A: Normally, you should know the voltage of the panel in
order to choose your inverter or battery bank or even if you want
to connect it directly to the consuming device. Isc represents the
maximum current produced by the panel; the current cannot reach
this value once in a circuit.
Q: I turn my system on but after couple of seconds, the
inverter turns itself off. What is the problem?
A: The load is too much and the inverter can't supply enough
current. You should disconnect or turn off some consuming devices.
Q: I have had my system for a while but it has stopped
working. How can I find the defected components?
A: The easiest test is starting from your panels. We assume
that you have a Multi-meter and you know how it works. Otherwise
we recommend you to find a local technician to do that because it
is dangerous to touch the components if you don't have any basic
knowledge of circuits/electricity.
Q: How should I install the panels in order to keep them in
A: It is recommended to put some space between the panel and
the roof in order to let fresh air pass under the panel. Since
some of the sunlight heats the panel, it will get hot if air is
not allowed to flow. The higher temperature can also affect the
Q: How can I test a panel?
A: First disconnect the panel from the system, then measure
the output voltage by a regular multi-meter and compare it to the
voltage written on the back of the panel. Normally under the
direct sun, the rated voltage is a bit higher. Make sure that the
multi-meter is on DC.
Q: The panel looks in good condition but the output voltage
from the panel is too low, how can I fix it?
A: Open the junction box at the back of the panel. If the
terminals are corroded or burned, you should change the junction
Q: I have opened the junction box and everything is in good
condition but the output voltage is too low. What is the problem?
A: The diodes are defected or they are in wrong direction.
Q: How can I test the diodes?
A: For testing a diode, you should take it out. Put your
Multi-meter on diode test. Connect the red wire of multi-meter to
the cathode of diode and the black wire to the anode. The cathode
of the diode is always marked by a dash or a line on the diode. If
you hear a beep or see a number on your digital Multi-meter, it
means that the diode is defected and you should change it. If not,
flip the diode and test it in other direction, you should see a
number or hear a beep. Otherwise the diode is defected and you
should change it. Make sure that you have performed the test in