Home Solar Power

Basic Function

The basic functions of a controller are quite simple, they prevent battery overcharge and block reverse current to prevent electrical current from flowing out of the batteries.

Overcharging batteries will at the least significantly reduce battery life and at worst damage the batteries to the point that they are unusable.

A charge controller is needed in virtually all solar power systems that utilize batteries. While the basic function of a charge controller is simple they might well be the most complicated part of the whole solar electric system.

Different Types

There are different types of controllers,  basic charge controllers are very simple on or off systems.  Pulse width modulation (PWM) and maximum power point tracker (MPPT) technologies are more electronically sophisticated, adjusting charging rates depending on the battery’s level, to allow charging closer to its maximum capacity.

How They Work

A simple or basic charge controller simply monitors the battery voltage stopping the charging when the battery voltage rises to a certain level, and restarting when it drops to a certain level. Inexpensive but they are inefficient and old technology.

The more modern PWM charge controllers are a type of charge controller that slowly reduces the charging current to avoid overheating the battery after it has reached the regulation setpoint.

At the same time, the system continues to send the highest amount of energy over the shortest period of time , which results in rapid charge and high efficiency.

This type of controller allows the batteries to be more fully charged with less stress on the battery, extending battery life. It can also keep batteries in a fully charged state (called “float”) indefinitely.

MPPT is the top of the line charge controller in the market. The MPPT is a high frequency converter that takes the DC input from the solar panels, changes it to high frequency AC, and converts it back down to a different DC voltage and current to exactly match the panels to the batteries.

It tracks the input power from your solar array and the voltage from your battery bank and adjusts the voltage for the highest amp output to the battery bank.

PWM And Mppt Chargers

The Mppt controller is capable of taking a higher voltage and ‘down converting’ it to a lower voltage while ‘up converting’ the amps.  Simply put, say your solar panels have an output of 24 volts and 5 amps and your battery bank is at 12 volts.

The Mppt will ‘down convert’ the voltage from 24V to12V and while doing this it will ‘up convert’ the amps to 10 amps. So you would have 12 volts and 10 amps to the batteries resulting in a more efficient system.

The PWM controller using the same system will take the higher voltage and ‘down convert’ it to a lower voltage but there is no up converting. So a simple way to look at it is you lose half the volts and half the amps, remember that the Mppt controller uses these down converted volts to double the amps.

MPPT charge controllers offer a potential increase in charging efficiency up to 30 % but of course they are much more expensive. Both systems work well but even at the higher cost MPPT charge controllers are best for your system.

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A solar inverter (photovoltaic inverter)  is a type of electrical inverter that is made to change the direct current (DC) electricity from your solar panels or wind turbines into alternating current (AC) for use with home appliances. Some inverters are designed to be connected to the power utility company’s grid.

Three Basic Types Of Solar Inverters

Stand-alone inverters: Used in independent solar energy systems or any energy system that is completely off the grid. The inverter is designed to draw  DC energy from batteries charged by solar panels or wind turbines, and change it to AC power.

Most stand-alone inverters also incorporate integral battery chargers and charge controllers to replenish the batteries. The charge controller regulates the input from the solar panels, regulates the battery output, and handles charging the batteries. Normally these do not interface in any way with the utility grid.

Grid Tie Inverters: Many solar inverters are designed to be connected to a utility grid and they contain special circuitry to precisely match the voltage and frequency of the power supplied by the utilities grid.

The inverter takes the electricity generated by your renewable energy system and sends it to the power distribution panel, from there the power may be used by  appliances within your home, or if not needed it will redirected to the utility grid.

This redirected energy is used by the other utility customers, and you receive some form of compensation for putting excess power into the grid. When there is no energy generated, utility power is pulled from the grid to provide power to your home.

Grid-tie inverters are designed to shut down automatically for safety reasons as required by law, upon the loss of the utilities power supply to protect the utility workers who are repairing the system.

Battery Backup Inverters: These are special inverters which are designed to draw energy from your battery bank, manage the battery charge via an on board charger and charge controller. The DC power is converted to AC power for your appliances and they export excess energy to the utility grid.

Unlike a standard grid tie inverter, these inverters are capable of supplying energy to your home during a utility outage, and are also required to disconnect from the grid during power outages.

No matter what type of system you use, an inverter is an integral part of it.

Here is a video, keep in mind that a small home system will be less complicated.

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A “grid-tie” solar energy system is designed to sell power back to the utility company and can be used with or without batteries.

Batteries Or No Batteries

If you are using batteries the power generated by your solar panels will be used to charge your batteries and any left over electricity generated by your  solar power system is directed onto the power grid. It adds to the overall total of kilowatt hours that can then be used by someone else.

With a battery less system if the grid supplied power goes out due to a storm or other malfunction, the user has no power for lights, furnace, refrigerators, etc, which could be powered by batteries for a limited amount of days.

There is a difference in cost between a battery less grid tie system and one with battery back-up. A battery-less system requires an inverter and a solar array or other renewable power source.

In addition to these two components, a battery grid-tie system requires several batteries, a charge controller for efficient battery recharging, breaker panels, circuit breakers, and enclosures to house the components.  A grid-tie system with battery back-up adds 10%-20% more cost over a stand-alone grid-tie system.

If you are not using batteries, any and all left over electricity generated by your residential solar power system and not used in your home, is directed onto the power grid, where it adds to the overall total of kilowatt hours available, and can then be used by everyone.

These systems will offset your utility usage, with the correct size system it will earn you a credit during the day that you would consume at night. These systems are easy to install and since some do not have batteries for back-up, the lack of batteries in these systems means no battery maintenance or replacements to worry about.

Grid-Tie systems are part of your overall solar system, the number and type of solar panels will determine how much energy you can produce, as will your geographic location. The DC power generated by your panels goes into an inverter.

Inverters

Inverters work by taking the DC power from the source, such as an array of solar panels or wind generators and converts it to AC power so it can be used by your appliances and fed into the grid.

The inverter must also synchronize its frequency with that of the grid (e.g. 60 Hz) using a local oscillator and limit the voltage to no higher than the grid voltage.

Grid-tie disconnects allow you to stop the flow of electricity between your solar power system and your electrical system. This provides for the safe maintenance of electrical and utility systems.  Grid-tie disconnects are also designed to quickly disconnect from the grid if the utility grid goes down.

This is an NEC requirement that ensures that in the event of a blackout, the grid tie inverter will shut down to prevent the energy it produces from harming any line workers who are sent to fix the power grid.

Selling Power Back To Your Utility Company

Ideally you want the utility company to buy back any excess electricity that you produce at the same retail rate that you buy electricity from them at. This is called net metering and is the simplest way to setup a grid-tie solar system.

In such a system you only have one utility kWh meter and it is allowed to spin in either direction depending on if you are buying or selling energy. If your solar power array produced enough electricity, your utility meter would begin to run backwards, and you earn credits on your electric bill.

In a non net metered system, the utility company will require that you install a second kWh meter to record any excess energy that you sell back to them and they will only pay you the wholesale rate.

To find out if your state offers “net metering” or any other incentives for installing a renewable energy system, Click Here.

Solar Power Information

Harnessing the power of the sun is on the rise and has lead to many different uses of solar power.

Most electric Power today is generated by turbines, using principals discovered by Michael Faraday in 1831. Most of these generating plants use the process of burning coal to power the turbines.

The Burning Of Coal

The burning of coal is one of the largest sources of carbon dioxide and other pollutants in this country and is a major contributor to global warming.

Economic concerns dictate that these plants will be around for many more years, as society is so dependent on electric power, that without it there would be chaos.

Solar Energy

Energy from solar power advanced rapidly during the space age as it was a great method for powering satellites.

Solar power is slowly growing in popularity, especially when used as a means to power your own household, giving you a free source of energy that is non polluting.

This reduces the strain on the public power grid, and it gives you the satisfaction of knowing that you are helping the environment.

You are also helping your wallet by eliminating the dreaded monthly power bill, which has grown into a large expense and will continue to get larger in the future.

The Different Uses Of Solar Power

Interestingly solar power has other uses besides generating electricity, for instance it can also be used to cook food. Solar cookers are more of a novelty, but they actually do work well and show another of the different uses of solar power.

Solar heating systems at home are being used by some families to take care of their own home’s heating needs. Solar thermal systems can maintain a steady temperature at your house without worrying about bills.

These systems are currently in use and have proven to be a valuable resource to many people. Just one more of the many uses of the power of the sun.

The use of solar energy to power traffic signs, emergency roadside phones, and other similar applications has been growing in popularity lately. There are many marine applications like the powering of remote buoys for example.

Solar power is being used in japan to charge electric vehicles, there is an interesting article on this at the green autoblog, and a similar station has just been opened in Brooklyn NY, article at brooklynpaper.com

Of course the use of solar power in communication satellites has made today’s cell phones and other related applications possible.

Solar Power For Your Home
There are many people who have always wanted to eliminate their power bill and help the environment but the very high cost has understandably held them back.

Recently new developments in the solar energy field has made it possible for just about anyone to have their own solar powered home. You can have a professionally installed system, buy a kit and install it yourself, or build an entire system on your own.

Thousands of people have actually built their own solar systems at a very low cost, using materials that are readily available just about anywhere.

Which ever option fits your needs, of all the different uses of solar power, home solar systems is your best bet to reduce your power bill and to help reduce pollution.

Home Solar Power

Using home solar power systems will help the problem of decreasing oil supplies. This country is facing a serious two headed energy crisis.

First off is the use of fossil fuels. The problem with this is the ever increasing prices, and the dependence on having to get these resources from overseas suppliers that can shut off the supply at any time.

Will Oil Run Dry?

Contrary to popular belief there are tremendous petroleum resources still available in this country, like oil shale and oil sands for instance. That being said, the process of extracting usable oil products from these resources is extremely complicated and very expensive.

So while oil is probably not going to suddenly run dry, decreasing supplies of relatively cheap oil only means increasing prices of the harder to get resources.

For families already struggling to get by this is not a good prospect, and for those that think this is in the future, you only need to look back a short time to when oil prices took a huge jump. And this is just the beginning, ever higher rising prices are inevitable.

Pollution And Oil

The second problem and the one that is considered the worse of the two is pollution. Bad air quality and the threat of global warming is real and it is not going to go away as long as the burning of fossil fuels continue to add to the problem.

This country has been dependent on this form of energy for the last 150 years. Initially people were not aware of the consequences, but we now are beginning to realize what they are.

Unfortunately this form of power is deeply entrenched and will be around for a long time. Additionally the government has been slow to react and make any changes, even with the knowledge of increasing pollution. That means it is has been left up to the individual person to act.

The Abundance Of Solar Energy

The sun’s energy or solar energy is the most abundant form of energy available on earth, it is time to take advantage of it. What most people do not realize is that switching to solar power has now became affordable to everyone. There are three options:

• Build Your Own. Solar cells have became quite inexpensive lately, using these and materials that are readily available at your own local home store you can make your own home solar power system. These home solar systems are not only cheap to build, they are very reliable, low on maintenance, and are a great investment for your homes power supply. With a good manual they are surprisingly easy to build.

• Purchase A Kit. Everything you need delivered to your home. Like homemade project, only much easier to put together, as all the measuring and cutting has been done for you. They are also very reliable, low on maintenance, and easy to assemble, but do cost substantially more than a do it yourself project.

• Professional Installation. Sit back and let a reputable company do all the work. More and more home solar power companies are converting homes to solar energy. The cost associated with this plan is quite high, but if you can afford the cost it is a great option.

With decreasing oil supplies and increasing pollution, the time has come to not only help the environment but to reduce, or even end your monthly power bills. Convert to home solar power today.