Beyond The Solar Panels

Mon, 2011-06-06 12:06

Sure, the solar panels are an important part of the system – perhaps the most important part. However, the job doesn’t end when you slide the last solar panel into the rack. In fact, the job is just beginning. Without proper converters, wiring, fuses ,and grounding devices, the solar panels will be ineffective at best, or dangerous at worst.

Below are other components of a solar system that you must consider during installation.

  • Solar Panels: A general (and very rough) rule of thumb is to install one 50-watt PV module for each person in a household. This allots each inhabitant approximately 250 watts (5 hours of sunlight) per day. Finally, for most North American cities, the solar panels should tilt 45-65 degrees from horizontal in order to maximize solar radiation capture.
  • Controller: In its most basic form, the controller makes sure the system is operating smoothly, efficiently, and effectively. Many experienced PV installers will provide an additional digital readout with multiple voltage and amp-hour readings that can monitor system and controller performance.
  • Wiring: The amount of power a wire can carry is related to how hot it can safely get. Wires have resistance, and, as power flows through them, that resistance causes heat to build up. The more power you put through a wire, the hotter it gets. PV systems do generate a “low” voltage (12 volts), but there is less tolerance for voltage drops in these systems than in the typical 120/240 household voltage systems. This makes choosing a wire size that can handle the load very important. If you do not have the knowledge necessary to successfully select correct wiring, it is necessary to contact an electrician or electrical engineer.
  • Battery: The size of the battery depends on the amount of electricity storage the client desires and to what extent the home is connected to the grid. For a standard 12 VDC system, you will need two batteries if the system is completely disconnected form the grid. The Trojan L16 battery is generally considered the best on the market.
  • Inverter: Most American appliances run on AC. Solar systems provide DC power. Thus, an inverter is needed to convert the 12-48 volts of direct current to the alternating currents used by most appliances. Most inverters on the market today operate between 87% and 98% efficiency ranges. When purchasing an inverter, consider the following factors:
    • Reliability and safety: Look for a company that has been in business over ten years.
    • Low battery voltage protection: Protects the battery from excessive discharge. A high setting allows the user to leave the battery unattended without harming the battery.
    • Over current protection: Prevents inverter failure in the event of a sudden high current.
    • Thermally activated cooling fan: Automatically maintains optimal temperature.
  • Fuses and Disconnects: It is essential to have a knowledgeable electrical engineer or contractor design and install proper fuse and disconnect protection. According to, “many PV systems use readily vailable low-voltage automotive and RV/marine type fuses. These range between ¼” blade fuses, ‘SEA’ fuse blocks, Class ‘T’, ATO/ATC Powerhouse Fuse blocks; or other in-line fuse holders.”
  • Grounding: In a word, grounding means connected to the Earth. It prevents surges in the event of a lightening strike or other electrical interference. If the home is connected to a utility grid, the AC system is already grounded. Do not ground the solar DC system to the AC system. This creates loops, which negate the positive effects of grounding in the first place. Ground the DC solar panel system and its associated components separately from all other systems.

What’s It Going To Cost?
PV systems typically range between $8 - $30/watts, depending on variables such as location, number of PV panels, orientation, system design, configuration, varying energy loads, as well as the ever-changing market supply, demand, and technology. This range is an average. Below is the estimated cost of installing a PV system that will be completely independent of the grid and will produce enough power to power the lights and other simple appliances. Without adding major components to this estimated system, it is possible to increase the power output up to three times this 12-volt DC system.

Component Cost of Component Quantity Total Cost
 Solar Panel     $400   $1200 
 Battery $250  $500 
 Controller $200  $200 
Fuses, Disconnects, Circuit Breakers  $80 N/A  $80 
 Wiring $300  N/A  $300 
 Inverter $300  $300 
 Voltmeter $40  $40 

Total Cost - $2620


If you are interested in learning more about solar check out Everblue's Solar PV Bootcamp page or call us today at 800-460-2575.

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