SolarDesignTools provides free interactive online design tools for Electric Solar Power energy systems. This includes determining the required number of solar panels, how many batteries will be needed, calculating wire sizes, a solar radiation chart, example system pictorials, and more.
Try this example of an interactive electric Solar Power Simulator to see how Solar Energy systems work.

Home / Overview Starting Guide System Sizing Tool Battery Designer Wire Size Calculator Tips & Strategies Terms & Definitions
Solar Panels Charge Controllers Storage Batteries Inverters/Generators Meters & Monitoring Solar Radiation Wiring Diagrams

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Solar Power Overview
The main components of a Solar Power Energy System are : The Solar Panels which feed directly into a Charge Controller. The Charge Controller charges the Batteries. The Batteries connect to the Power Inverter which converts the DC voltage to regular 120 Volt AC house power. Output from the Inverter goes to a standard AC Breaker Box and then to the outlets just like a conventional system.
An Electric Solar Power Energy system uses photovoltaic cells to directly convert solar radiation into electricity. This is ideal because there are no moving parts, no emissions of any kind, and therefore no maintenance or pollution. The more solar panels that are installed the more electrical energy is created.

This would be the perfect energy source if the efficiency of photovoltaic solar cells were higher. Unfortunately, photovoltaic cells are typically only about 15 percent efficient. However continued research will increase solar cell efficiency and become less expensive as more progress is made. Small systems for remote cabins or small homes can start around $10,000 and larger family homes can easily reach $50,000 for a completely self sufficient system.

A more practical approach that is more affordable is a Grid-Tie system. This type of system is connected to the existing electrical grid and does not require batteries (which are expensive). All you need is a grid-tie type inverter and you just add as many Solar Panels as you can afford. This way you can reduce your electric bill and actually run the electric meter backwards and still have plenty of electricity available from the grid for larger loads or when there is little or no sun.

Solar Panels
The Solar Panels are the generators of the electricity. Using the Solar Panel Sizing tool will allow you to determine how many you will need. One variable is how many watts of power an individual Solar Panel generates. This usually varies from 100 to 200 watts per Solar Panel. Also, you will need to determine how much power you need the Solar Panels to provide. The number of Solar Panels you will need can be calculated by the total watts of power you will need and the watts per Solar Panel. The System Sizing Tool allows you to do this.
Charge Controllers
Because the sun's intensity will change during the day, especially with clouds passing by and because as the batteries get closer to a full charge, they will want less voltage, charging must be controlled. It is the job of the Charge Controller to regulate the voltage applied to the batteries. This allows the batteries to receive maximum charge when they need it but not be overcharged. The two most popular and efficient types of charge controllers are PWM and MPPT. These are quality charge controllers and maximize performance.
If you want a stand alone system that does not require the existing electrical grid, you will have to use storage batteries. The batteries will charge up and store power when there is sunshine and deliver it later. A DC to AC power inverter is required to convert the 12 Volt DC battery voltage to usable 120 Volt AC power which most appliances use. A small cabin might get away with all 12 Volt DC equipment, but a normal house will need 120 Volt AC power to run modern appliances, lighting, computers, etc. Use our Battery Bank Designer to show the various combinations of battery bank voltage and power (capacity).
To use the energy stored in your Battery Bank, you need a DC to AC Power Inverter. It changes the low voltage DC to 120 Volts AC for standard household appliances. There are 3 basic types. First is a Square Wave Inverter usually designed to plug into a car's 12 Volt cigarette lighter outlet. These are cheap to buy but very poor quality. Forget them. The next step up is a Modified Sine Wave Inverter and is satisfactory for most applications. However, if you want really clean power, buy a true Sine Wave Inverter. A high quality Sine Wave Inverter often has a cleaner power footprint than your local utility company. It's the way to go.

Home / Overview Starting Guide System Sizing Tool Battery Designer Wire Size Calculator Tips & Strategies Terms & Definitions
Solar Panels Charge Controllers Storage Batteries Inverters/Generators Meters & Monitoring Solar Radiation Wiring Diagrams

DISCLAIMER : The information and suggestions on this website are generally proven and accepted standards and techniques. They are, however, not meant to supersede local zoning laws or the recommendations of a licensed electrician. Always read the instructions provided with your equipment and observe all safety precautions.