Solar power components convert sunlight into electricity that can power equipment from home appliances to an RV.
on September 8 2013
Solar panels are made up of photovoltaic cells, which harness the sun’s energy to produce electricity. The electrical current exits the panel through a wire as 12-volt, direct current (DC). Energy is stored in batteries and converted to alternating current (AC) using an off-grid inverter to power off-grid appliances. Solar power also can be fed into the electric grid to supplement grid-tied power.
Solar power is at the forefront of the fast-growing green, renewable energy movement. Using solar power, you can feel good about reducing your impact on the earth by offsetting your use of nonrenewable resources, while saving money on your electric bill.
This buying guide provides an overview of solar power, including its uses, advantages and the components you will need to safely harness the power of the sun, whether supplementing your grid power or for an off-grid application.
Factors to Consider
• Advantages of Solar Power
- Economical, clean, low maintenance
• Solar Applications
- Off-grid or grid tied
• System Components
- Solar panels, charge controller, batteries, power inverter, DC disconnect
Advantages of Solar Power
— The rising cost of electricity has led people to search for ways to cut costs related to powering
their homes and appliances or running their RVs. While the up-front cost of installing solar panels can seem
expensive, their 25+ year lifespan with almost no maintenance costs, coupled with the free energy provided by
the sun, makes them a cost-effective way to offset your utility bill. In addition, government rebates and tax
breaks can help with the cost of installing solar panels. To learn more about rebates in your area, visit
— Power from the sun is clean and infinitely renewable. Solar power emits no fumes and creates no
greenhouse gases or carbon emissions. It is one of the most environmentally friendly energy solutions
available. In addition, solar power is silent, creating no noise pollution.
• Low maintenance
— Solar panels are self-sustaining. They have an expected life span of 25+ years
and require almost no maintenance.
• Off-grid power
— tand-alone, off-grid power can be provided to a remote cabin, to RVs, boats and other
vehicles, to electric fences, or as backup power to essential appliances, in the same way you might use a
Because solar panels do not store electricity and only generate power during daylight hours, off-grid power
works by storing solar power in a deep-cell battery or bank of batteries. The battery power is then used
directly to run an RV or is converted to AC using an off-grid inverter to power appliances in a cabin.
Solar power kits often include everything homeowners need to install off-grid solar panels themselves.
Our How to Install a 60-Watt Solar Power Backup Kit Project Guide shows an off-grid installation.
• Grid-tied power
— If your house is connected to the electrical grid (your home uses traditional electric
power from a utility company), you can use solar power to offset utility-provided electricity. Connecting
solar panels directly into the grid can save you money. If you want to use solar power as backup when
the electricity goes out, you will need to connect batteries to your solar power system. Solar panels
convert the sun’s energy to electricity, but do not store electricity. Without batteries to store the solar
electricity, you will not be able to use grid-tied solar power in the event your electricity goes out.
During peak sun hours if your grid-tied system is producing more electricity than is being consumed, the
solar-generated power may be fed into the grid, causing your electric meter to run backwards. In some
states, your utility account may be credited with the amount your solar panels feed into the grid.
The installation of solar panels into the grid to power your home involves working with high-voltage electricity.
You should consider using a professional solar installer. Additionally, tax refunds and rebates available from
federal, state and local governments may require you to use a certified solar installer. Visit www.dsireusa.org
for more information on rebates available in your area. Our Solar Savings Calculator can help you determine
your solar panel needs.
The Home Depot offers Home Solar Power Installations
in select parts of the country.
Our Solar Diagram (PDF) shows you how the components of a solar power system work together.
• Solar panels
— Photovoltaic solar panels are the key to solar power. The panels are made up of photovoltaic
cells that absorb the sun’s energy and convert it to electrical current. The three most popular types of solar
panels on the market today are polycrystalline, monocrystalline and amorphous. There are advantages and
disadvantages to each. Keep the following in mind when considering which panels might be best for your
• Polycrystalline panels - Are made from a block of silicon with many different crystals. They are rigid,
efficient and should be used in areas with high sun exposure.
• Monocrystalline solar panels - Are made of one silicon crystal. They are more expensive but also
more efficient than polycrystalline panels.
• Amorphous panels (also called thin-film panels) - Are flexible and easier to work with than the rigid
poly and monocrystalline. Amorphous panels also work in all daylight conditions, making them ideal
for areas with lower sun exposure.
The power output of solar panels is stated in watts, which is calculated by multiplying the rated voltage by
the rated amperage. To determine the number of watt-hours per day that a solar panel can generate, multiply
the watts by the number of peak sun hours in your area. For example, a 60-watt solar panel in an area with
6 peak sun hours—the average amount of sun available per day throughout the year and the time during
which the solar panels are producing the most power—would generate 360 watt-hours of power per day.
Solar panels can be wired together to increase their power output.
Solar panels need to be installed where they can absorb the most sunlight every day, often on the roof of a
house or RV. They can also be installed on the ground or on a pole. In the northern hemisphere the ideal
location is facing solar south and in the southern hemisphere, solar north.
• Charge controller
— Charge controllers (also known as charge regulators) regulate the voltage going
into your battery and protect battery discharge at night. The charge controller allows more current to flow
when the battery charge is low and halts current if the battery is over-charged. A charge controller is
essential because the battery can be damaged by the fluctuating charge if a solar panel is connected directly
to it. Be sure the charge controller you purchase is compatible with the solar panels and batteries in your
— Solar panels convert the sun’s energy to electricity and batteries store the electricity. Unless you
are connecting your panels to the electric grid, you will need a battery or bank of batteries to store the power
the panels create. Deep cycle batteries are designed to be discharged and recharged hundreds of times
making them the best choice for use with solar panels.
Like solar panels, batteries can be wired together to provide as much power storage capacity as needed.
Batteries are rated in amp hours (ah), a measure of the amount of current the battery can supply during a
specific number of hours.
• Power Inverter
— The power inverter converts DC power from the batteries to AC power, which is the
electricity common in homes. Inverters come in two types, modified sine wave and pure sine wave
• Modified sine wave inverters - are less expensive than pure sine wave inverters. Most of
the appliances or electronics in your home will run using a modified sine wave inverter.
Some common equipment should not be run from a modified sine wave inverter: laser printers
can be damaged, some motors may run hot, and you may hear a buzz sound from amplifiers,
fans and compact fluorescent lights.
• Pure sine wave power - is the same power provided by utility companies. Your appliances
or electronics will function properly
NOTE: If you are using battery power only, such as when powering an RV, you will not need an inverter.
If you want to power any home appliances, however, whether grid-tied or off-grid, you will need an
• DC disconnect
— Essential in a grid-tied system, but not needed in an off-grid system, a DC disconnect
switch is installed near the point where the solar panel cables enter the house. This switch turns off the
power connection to the solar panels so you can safely work on them if necessary.