Batteries: Flooded Lead Acid
Batteries: Sealed Agm
Batteries: Sealed Gel Cell
Books, Classes & Educational Videos
Solar Electric and Passive Solar
Solar Hot Water Systems
Cables & Wiring
Battery To Inverter
Wire By The Foot
Wiring For Solar Panels
Solar Charge Controllers
Solar Lighting Controllers
AC Charge Controllers
Constant Voltage Regulator
Diversion Load Controllers
DC Voltage Converters
Enclosures, Electrical and Safety
Miscellaneous Electrical Parts
NEC Compliant Safety Labels
Outback Flexware Components
Overcurrent Devices (Fuses & Breakers)
Switch Gear Disconnects
How To SectionInverters
Export Inverters (230V 50Hz)
Mobile / RV Inverters
Off-Grid: (No Utility-Needs Batteries)
On-Grid & Off-Grid Capable Inverters
On-Grid: (Grid Intertie-No Batteries)
Kits and Package Deals
Grid-Tied with Battery Backup
Off-Grid Cabin Systems
Off-Grid Residential Systems
Other Packages and Special Deals
RV Solar Packages
& Site Analysis
Meters & Battery Monitors
Solar Site Analysis Tools
Wind Data Instruments
Solar Panel Mounts & Trackers
RV & Specialty
Side Of Pole
Top Of Pole
1 to 50 Watt Solar Panels
51 to 99 Watt Solar Panels
100 to 149 Watts Solar Panels
150 Watts & Up Solar Panels
Flexible / Rollable Solar Panels
Foldable Solar Panels
Solar Panels by the Pallet
BIPV - Building Intergrated Photovoltaics
VAWT Wind Turbines (Electric)
HAWT Wind Turbines (Electric)
Wind Turbine Towers
Wind Data Instruments
Wind Power Education
Components for your Solar Panel (Photovoltaic) System
Solar electric systems are a popular choice among renewable energy options due to the relatively low maintenance requirements and the long lifetime of many of the system components. Because there are no moving parts, and thus little chance of mechanical failure, most solar electric systems will continue to produce power for 30 years or more!
Although some smaller solar electric systems can be relatively straightforward to install, many people choose to hire installers. Regardless of whether you plan to install an cabin system yourself or have a contractor install a system, you will benefit from understanding and properly maintaining each component in your system.
Modules aka Solar Panels, Solar Electric Panels or PV Modules
PV modules are known as solar panels or solar electric panels. We'll be using the terms interchangeably throughout this article although "PV Module" is the more technically correct terminology.
panels provide electricity from sunlight. They are typically made
of silicon crystal slices called cells, glass, a polymer backing,
and aluminum framing. Solar panels can vary in type, size, shape,
and color. In most cases the size of a PV module refers
to the panels rated output wattage or electricity generating
potential. Solar panels also have voltage ratings. Those with of 12
or 24 Volts are generally preferred for off-grid systems with battery
banks. Other solar panels come in less common nominal voltages such
as 18, 42, and even 60 Volts. These modules are typically used in
grid-tied applications to accommodate the working of grid-tied inverters.
Solar panels can be used alone or combined into arrays by wiring them
in or in to achieve the needed . The price of most large residential
or commercial PV modules can range between $2.20 and $3.40 per rated
PV system terminology, everything besides the PV modules themselves
is called balance of system or BOS. Well go over
the main BOS components below, one at a time, in the direction of
electricity flow through a typical system.
Solar panel mounting systems include hardware to permanently affix the array to either a roof, a pole, or the ground. These systems are typically made of aluminum and are selected based on the specific model and number of modules in the array as well as the desired physical configuration. Solar Panels work best at cooler temperatures, and proper mounting allows for cooling airflow around the modules. For all locations, wind loading is an installation factor, and it is extremely important to design and pour the cement foundation properly for any pole mount. are a pole mount option to increase energy production by moving the array to face it into the sunlight as the sun moves across the sky. A solar array on a tracker will produce more energy than a fixed array. Trackers are often used in water pumping applications. The cost of a tracker can be significant, and due to the possibility of breakdown, they are best recommended to the mechanically inclined. The cost of a mounting system varies based on the number of modules and type of mount. The average cost is between $250 and $1,000 for a fixed array and $2,000 and up for a solar tracker. Another cost-estimating factor for mounting racks is $0.50 to $1.00 per rated array Watt.
combiner box is an often-overlooked, yet essential part of most solar
electric systems. The combiner box is an electrical enclosure which
allows multiple of solar panels to be combined in parallel. For example,
if you want to wire together two 12 Volt panels for your 12 Volt system,
you will wire each panels output directly to terminals inside
the combiner box. From the combiner box you can then run just one
positive and one negative wire (in appropriate conduit) to the next
system component, the charge controller. The combiner box will also
house series string fuses or circuit breakers. These boxes are usually
outdoor-rated, and meant for placement right next to the array or
solar panels. Combiner boxes usually cost between $80 and $140 USD.
Every solar electric system with batteries should have a solar charge controller. A charge controller regulates the amount of current the PV modules feed into a battery bank. Their main function is to prevent overcharging of the batteries, but charge controllers also block battery bank current from leaking back into the photovoltaic array at night or on cloudy days, draining the battery bank.
The two main types are PWM (Pulse Width Modulated) and MPPT ( Tracking). PWM technology is older and more commonly used on smaller solar arrays. Choose a PWM charge controller that is the same as your solar array and battery bank. The controller must also have enough capacity (in rated Amps) to handle the total current of the solar array safely. MPPT charge controllers can track the maximum power point of a solar array and deliver 10-25% more power than a PWM controller could do for the same array. They do this by converting excess voltage into usable current. Another feature of MPPT charge controllers is their ability to accept higher voltage from the solar array for output to a lower voltage battery bank. Charge controllers typically cost between $50 and $750 depending on size, type and features.
for Solar Electric Systems
Batteries chemically store electrical energy in renewable energy systems. They come in several voltages, but the most common varieties are 6 Volt and 12 Volt. The three types of batteries that are most common to RE systems are:
lead-acid batteries are the most cost-effective variety. They require
maintenance that involves monitoring voltage, adding water, and occasional
. Additionally, FLA batteries vent hydrogen under heavy charging so
they must be stored in a ventilated enclosure. Because of the maintenance
issues of FLAs, some people prefer sealed batteries, which dont
require maintenance. Since they are sealed, they do not require watering,
nor do they typically vent any gasses. AGM batteries cost more and
are more sensitive to overcharging than FLAs.
An inverter takes (DC) from batteries and turns it into (AC) which is used to run most common electrical loads. There are two main classes of inverters, or grid-capable and , standalone units.
Off-grid inverters require batteries for storage. Straight grid-tied inverters dont use batteries and grid-capable inverters can work either with or without batteries depending on system design. There is a wide range of available inverter features suited to differing system needs and situations. Some inverters have integrated AC chargers so that they can use AC power from the grid to charge the batteries during periods of low sun. Inverters with integrated AC chargers can also be used in conjunction with fossil fuel-based generators for battery charging or running very large loads. Off-grid inverters meant for whole-home usage must have appropriate conduit boxes and accessories that enclose all live wiring. Usually, whole-home inverters are rated to produce 2,000 Watts continuous power or more. Off-grid inverters come in two flavors: those producing current and those producing current. Some appliances (compressors or other inductive loads) and many sensitive electronics (cordless battery chargers, computers, stereos, etc.) will not function properly on modified sine wave power. Off-grid inverters can cost anywhere between $100 to $3,000 depending on size and type.
straight grid-tied inverter connects directly to the utility grid
without the use of batteries. With these inverters, when the grid
goes down the PV system also goes down to protect service linemen
from injury due to unexpected live lines during outages.
A grid-capable inverter can both connect to the grid and use batteries,
which allows for the possibility of back-up power during outages.
Grid-connected inverters also generally produce 2,000 Watts or more
and cost about $2,000 to $4,000.
() code-compliant system can live without disconnects! The DC and
AC disconnects of a PV system are manual switches that are capable
of cutting off power to and from the inverter. Some inverters have
disconnects with switches integrated into their structure. Other systems
use an integrated power panel to support the inverter(s) and their
associated disconnects in an organized arrangement. In still other
cases, you will need to purchase the appropriate disconnects separately
to work with an inverter. The disconnects are used by service personnel
or authorized persons (fire/police/electric workers) to stop power
from a renewable energy system reaching the inverter. (Don't forget
that there are capacitors in most inverters that can hold a lethal
charge for up to several minutes after incoming current is cut off!
Consult the inverter manual for safe access times.) Disconnection
prevents the current being produced from going beyond the disconnect
point to a downed utility grid or damaged component. Homeowners or
authorized personnel can use disconnects to de-energize a system for
maintenance or service. Disconnects can range in cost from $100 to
connectors, conduit and brackets -- oh my! This category includes
everything you need to connect all the parts together safely and securely.
As with most specialized technologies, there are many parts and tools
involved in the proper installation of a safe and effective PV system.
It is the responsibility of the installer to have a thorough understanding
of them and of all the rules and regulations pertaining to solar electric
installations (NEC Section 690 is key here). Gaining the knowledge
needed to design and install a safe, efficient system not only ensures
that your system will meet your needs effectively but also keeps you
and your home safe and helps to promote the acceptance of renewable
energy as a mainstream energy source.
We are thrilled that you are pursuing a PV system. Whether you choose to install the system on your own or whether you hire a professional installer, please be sure to adhere to National Electric Code for safety. Our PV installation Books, Classes & Educational Videos make great references as well.