SolarPowerSimulator.com is a Free Interactive Simulation of a Solar Power PV (PhotoVoltaic) Energy System. Increase & Decrease the Sun intensity to produce more power. Turn various appliances On & Off to see battery charging/discharging & power consumption.
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A Basic Solar Power System Tutorial

Solar Panel Tutorial

This basic tutorial of Solar Panels will give you a general understanding of the role they play in a photovoltaic system. Solar Panels are the generators of the electricity. Solar panels generate free power from the sun by converting sunlight to electricity with no moving parts, zero emissions, and no repairs or maintenance. Donald Trump recently commented that 'solar' was not the way to go because the panels burn themselves out in 10 years. Completely FALSE. Many of the original solar panels from the early 70's when they were invented for the Space Program are still working today. I personally own 8 solar panels that are over 25 years old!

The solar panel, the first component of a electric solar energy system, is a collection of individual silicon cells that generate electricity directly from sunlight. The photons (light particles) produce an electrical current as they strike the surface of the silicon substrate of the individual cells. A single solar cell produces only about .5 volts. But you can wire as many of them in series as you need to achieve the desired output voltage. A typical Solar Panel can be purchased in 12 Volt, 24 Volt, or even 48 Volt configurations. All this power is stored in batteries for use when the Solar Panels are not generating electricity. (When it is cloudy or at night)

Unfortunately solar panels are still relatively expensive, but prices are coming down. 10 years ago you could figure on paying $5.00 per watt. That would make a typical 100 watt solar panel about $500.00 (USD). And, you can still pay that much for a 12 Volt panel if you don't shop around. Now, however, you can find solar panels for about $2.00 per watt or less by purchasing larger (higher wattage) panels at higher operating voltages (usually 24 or 48 Volts).

Charge Controller Tutorial

Charging the Batteries must be controlled because the sun's intensity will vary during the day, especially with clouds passing by and because as the batteries get closer to a full charge, they will draw less power. 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 (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking). A PWM (Pulse Width Modulation) type of charger varies the timing of the charging pulses to maintain the appropriate voltage on the batteries depending on the charge state. In other words, if the batteries are low, the pulse duration is longer thereby delivering more charging voltage to the batteries. If the batteries are closer to full, then the charging pulse duration is much shorter. A MPPT (Maximum Power Point Tracking) uses even more sophisticated techniques to gain the maximum power from the sun.

These are quality charge controllers and maximize performance. A charge controller is an essential part of any photovoltaic system with multiple Solar Panels. See the tutorial on Batteries for more information.

Battery Tutorial

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 through the Charge Controller and store power when there is sunshine and deliver it later when there is little or no sun. 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.

Batteries come in many different configurations. The actual physical size is a combination of the voltage and the power capacity of the battery usually expressed as AmpHours. The overall voltage of the battery bank needs to match the charging voltage from the solar panels. For example: If you used four 6 Volt batteries wired in series, this would give you a 24 Volt battery bank. There are many combinations of total voltage and total power (capacity). There are two basic categories or types of batteries. Flooded and Sealed. A flooded battery has filler caps and water must be added periodically to maintain the electrolyte level. Flooded batteries are probably the most popular because they are less expensive. The main problem with these batteries, though, is they emit hydrogen gas during the charging process causing corrosion of the cable connectors and other metal parts. Also, since hydrogen gas is explosive, venting is required.

Sealed batteries eliminate all these problems. They do not require water, do not outgas hydrogen, do not cause corrosion, and no venting is required. I believe the extra cost is well justified. The first time you have to shut your system down, remove all the cables/connectors, and repair/clean or replace them entirely, I think you will agree. AGM (absorbed glass mat) batteries are a popular sealed battery. While both types use lead/acid chemistry, the sealed batteries use a paste rather than liquid. Another plus for AGM sealed batteries is that you can keep them indoors where they will stay warmer since they don't outgas. By the way, most battery specifications are based on a 77 degree temperature. If they are kept in a vented box outside, their performance will suffer dramatically when they are cold. Do not confuse sealed batteries with maintenance free batteries. Maintenance free batteries are still flooded batteries, but you can't add water. They still emit hydrogen gas when charging and corrode cable/connectors, just not as bad. When their electrolyte levels do fall, they just go bad and need to be replaced.

AC to DC Inverter Tutorial
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.
Another type of Inverter is the Grid Tie Inverter. With this type of Inverter you will not need any Batteries but you will not have any back-up power if the power goes out. The main idea of a Grid Tie System is to use Solar Panels for free electricity when you have it but switch to the Power Company if you need more power than your Solar Panels can provide. When you produce extra power, your Electric Meter will run backwards and the power is sold back to the Power Company. If you have enough Solar Panels, you could conceivably have free power all Summer, selling the excess to the Power Company and then buy it back in the Winter when your Solar Panels are producing little or no power.
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More FREE Simulations

Play our Free Online Interactive Nuclear Power Simulator game. Operate a Nuclear Power Plant and try to maintain maximum power and not have a radioactive MeltDown! See if you can generate the full 100 MegaWatt output of the power plant and light up all the city lights.

Adjust the reactor Control Rods, the Primary Coolant flow, the Secondary Coolant flow, and keep the Heat Exchanger, the Steam Turbine, the AC Generator, and other reactor components below their damage threshold.

If you're careful, you can make a healthy profit and not have to spend your cash repairing the reactor components. Try it. It's free and it's FUN. PLAY NOW !

While not really a game, Solar Design Tools is a very useful tool for calculating the number of Solar Panels and Batteries a real Solar Power Electric Energy System would require. Simply click on the appliances you would be using & the estimated hours of daily use & the System Sizing Tool will calculate the required Solar Panels & Battery Bank size. An overview of Solar Power Energy Systems is also presented with an explanation of all the major components of various sizes of systems including the wiring diagrams that show how it all goes together. Unlike some design tools, the System Sizing tool requires no typing with its easy point & click interface.
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