The efficiency of a solar panel is determined as the ration of power out or electricity; to power in or solar irradience striking the panel.? Usually it is described as a percentage.

Think of irradience as the power of the sunlight striking a given area at a given moment.? Usually in Watts per meter squared.? Since the sun’s irradience is constantly changing due to the earths’ rotation, an average figure normally used by most manufacturers is 1000 w/m?.? This will occur around noon on a clear day.

The panel’s manufacturer lists the maximum power in watts on the panel’s nameplate and from the values given, you can calculate the efficiency by dividing maximum power by 1000 times the surface area of the panel.

Example:

For a 40 watt panel with .5m? surface area, the formula would look like this..

70????????????????????????????????????????????????????????? 70
_________????????????????????????????????????? ________
1000 x .5 ? ? ? ? ? ? ? ? =????????????????????????? 500 ? ? ? ? ? ? ? ? ? ?? = .14 ? or? 14%

Note:? Remember the 1000 used is an industry constant in reference to 1000 watts per meter square of solar irradience.

For informational purposes, solar panels are actually called solar modules in the solar industry.?? Try not to get confused with all the differing terminologies used.? The field is developing rapidly and self-education is undoubtedly your best path to understanding the world of solar energy.

What? You don’t want to sink ten of thousands of dollars into a professionally installed solar power system? You want cheap solar panels?? With some smart shopping and DIY ingenuity, you can harness the sun for less.My first piece of advice for people looking for cheap solar panels is to AVOID OLD ADVICE.? Solar panel technology is in a stage of rapid development.? First generation solar panels are pricey because of the expensive materials and the skilled labor required to produce the cells.? Second generation solar panels hold some promise of affordability, but there is no way of knowing just how low they will go.

My second piece of advice is that FREE is the cheapest that you can get.? Free solar panels are often used and/or damaged.? They may or may not meet your needs.

The sticker price is only part of the cost equation. You have to compare efficiencies as well. A cheap panel with a much lower efficiency than a more expensive one may take decades to pay for itself.

Photo Credit: geocam20000

Unlike PV solar panels, there is no limit to how low-tech you can go when heating water with the power of the sun. Modern systems use vacuum tubes and they are very efficient. A simple collector that uses a black surface encased in insulation and glass with copper piping running through it will work too. Very basic systems are commonly used to raise the temperature of swimming pools. They can also help reduce the cost of heating the running water that you use in your home. Even if you live far away from the equator, you can offset your water heating costs by 25% or more with a solar water heater. Sunnier places can approach a 100% savings.

If you are thinking about a DIY solar water heater there are three many things that you have to consider when comparing plans or making your own. These are COST, DURABILITY, and EFFICIENCY.

There is no point in spending more on your do it yourself project than it would cost to get a factory made, plug and play water heater. Good quality solar water heaters cost in the neighborhood of $5000. One of the cheapest looking plans that I could find on the internet used Coroplast as a collector. The designer was quite confident about the panel’s efficiency but he admitted that it may not be durable enough to install as a residential water heater. So basically his simple solar water heater excels in one of the three considerations but falls short on the other two.

I saw elsewhere that someone had a plan to convert a free supply of old fashioned cast iron radiators into solar collectors. It seems like a simple plan since these things are incredibly durable. In this case, two out of three is bad. While the plan is cheap and the end product would be durable, the efficiency of the system makes it nearly useless.

The most common type of DIY solar water heater is common because it has the best balance of durability, cost and efficiency. These plans typical involve a collector plate made from a conductive metal like copper or aluminum. This plate is coated on one side with black paint. Copper piping is attached to the back of the plate. This collector assembly is then housed in a basic frame with the coil side next to insulation and the plate side covered with glass. A panel like this can be plumbed to the hot water line for you home. Obviously, the secondary system should be between the solar panel and the outlets (faucets). It would be very inefficient to pump water that you had heated with gas or electricity up to your roof on a cold, cloudy day.

I just finished watching a video interview of a professional solar panel installer.? He explains the process of getting set up with residential solar panels step by step.? I like the last step best:

“Watch your meter start spinning backwards.”

Some of the other steps made me uncomfortable, like the one where you give SolarDave a big chunk of money. The process of obtaining permission from your local government sounds like a bit of a hassle as well. In the future, people in the solar power industry are hoping to see some standardization of the approval process. As things stand, the time and cost involved in getting a permit to put residential solar panel on your roof is all over the map.

There is a whole other layer of bureaucracy if you want your system to be tied into the grid.

One way for do-it-yourselfers to avoid some of the bureacracy is to put the solar panels someplace other than their roof.? Using them in a closed off-grid system simplifies things even more.

Thermal solar panels, the ones used to heat residental water, are said to pay for themselves in less than ten years.? Heating water with electricity in one of the biggest inefficiencies in the modern home.? A solar water heater will save your family $6 per month per person and reduce your carbon emissions by 3 tons per year.

Quote: “Photovoltaics is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.” From Nasa

This is the simplified explanation of how solar panels work. Solar energy hits the Earth as a particle that we refer to as a photon.? When a solar panel is bombarded with photons,? some of them are absorbed by the semi-conductor material (commonly silicon).? Each photon that is absorbed can potentially shake loose an electron.? An electric current is a flow of electrons.? Solar cells are constructed with materials that force the free electrons to flow in one direction, thus creating an electrical current.? A typical solar panel is composed of a group of solar cells joined in series and/or in parallel by a conductive material.

As I travel around the web and find simple solar oven ideas, I will post them on the site.

The following video is short and basically shows about how simple a solar cooker can get. For those of you starting out with home solar panels and projects, this is a great one to show how effective the sun’s power is.

Download the free Aluminum Solar Cooker Plan

httpv://www.youtube.com/watch?v=ENwEO6ekUds

The cost of solar panels is quite variable.   There is no upper limit to how much money you can spend on a residential solar power system.? I guess you are limited to some extent by the amount of surface area at your disposal.? The realistic number for a serious solar power system, one that is professionally installed and connected to the grid, is $20,000.?? The cost of professional installation is a pretty big portion of that round number.? Retailers of solar power components are now providing extensive advice to people who want to install their own components.

Experts are predicting that the cost of solar panels will drop in the future.

A portable unit that is suitable for a boat or RV can be had for less than $1000 but these units have very limited output.

The best bang for your buck is actually solar water heating.? A system can be installed for around $5000 and it can reduce your water heating costs from 50-100%.? If you presently use electricity to heat your water you can expect to have the unit pay for itself in just a few years.? The price for solar water heaters quite variable, I was able to find one that is made in China for $235 plus shipping.? The most expensive system on the market is equipped to provide in floor radiant heating for your home as well as hot water.? It costs almost $25,000.

Buying in bulk to save money is a strategy that we all know about.? Is their such a thing as buying solar panels in bulk?? Well, some suppliers have pallets packed and waiting for a buyer.? If you have? project that requires this many panels,? you can potentially save some money.

Photo Credits: TVentano / Haversack

Photo credit: docentjoyce

Portable panels practically shout the word FREEDOM. Whether your an outdoors type of person like the one in the above photo or a traveling business exec, you should recognize the advantages of being able to plug into the sun rather than search for an electrical outlet in a place that is strange and new.

There are many products that claim to provide a solution for people who want to power their portable electronics using solar power. Whenever a new one comes on the market, the popular technology bloggers are quick to review them and they are almost always found wanting. They can fail in three different ways. They can be too expensive. They can be too big to be portable in any practical way. They can fall short on the amount of power that they generate. Some products that are aggressively marketed actually fail on all three counts. Different reviewers will always have different standards by which they measure portable solar panels. I have seen a review where the blogger was quite happy to have a gadget that would just barely charge an iPod over the course of a full day of bright sunlight. I think it would be great to have a serviceable solar panel as part of the emergency kit in you car. Even if it was only good enough to partially charge your mobile phone, it could potentially save your life.

Building your own portable solution allows you to set and meet your own standards for cost, portability and power output. You may have to consider some compromises. A common strategy to maximize portability is to attach the solar panels to storage items that you would be taking with you anyway. Backpacks, laptop cases, handbags and more can be retrofitted with today’s flexible solar cells. If you want more power, you can build a purpose specific bike trailer.

If you are planning to use the panels to charge one or more DC powered devices, your system may not require a battery or an inverter.

Take a look at some systems and pricing as shown below from various stores. It will give you a good idea of retail cost according to watt delivery.

Portable Solar Panels And Units

When we talk about how much solar panels cost, the standard measure is in dollars per watt. The electricity that we buy from the grid is generally priced in dollars per kiloWatt hour. Solar panels generate at their full potential for about 5 hours per day. The average household pays for about 10,000 kWh per year. That is roughly equal to 1140 Watts 24/7 all year. If solar panels can only power for 5 hours per day (check here for Sun hours per day in your area) you need about 5000 watts worth of solar panels to meet average consumption needs.

Solar panels are presently available wholesale at a minimum of $3 per Watt. That means the cost of the panels alone will be $15,000.

I don’t have that kind of money burning a whole in my pocket, do you? There are lots of other less capital intensive ways to take advantage of solar power. You can build your own closed system that uses this alternative power for one of your needs. A small solar panel setup could easily power an LED lighting system. You could save some money by building a DC lighting system that wouldn’t require an inverter. Your laptop uses about 60 Watts. You should be able to build your own solar panels to power a laptop and some DC powered peripherals for a few hundred dollars.

The energy that comes from the sun is free.? Free solar panels, on the other hand, are hard to find.

You might be at a loss as to where to start looking for free solar panels.? Keep an eye out for solar panels that are being used to power traffic lighting and construction signage.? See if you can find contact information for the suppliers in the phone directory or on the panels themselves.? These businesses may have damaged solar panels taking up space in their garage.? They might be happy to let someone take them off their hands for little or no money.? Visiting in person is more effective than trying to convince someone over the phone.? Be very friendly because you never know which contact has the potential to become a continuous source of useful free stuff.? Bring a meter with you .? You should buy (or borrow) a meter that can measure the volts and amps.? You want to avoid wasting you time, gas and possibly money on a solar panel that does not generate any electricity.

Solar cells are easily damaged, but they can be used to build less than perfect looking solar panels.? If you can’t find a source of free damaged solar cells, look to some of the bigger retailers for cheap grab bags of damaged cells.?? These kits can be useful for practicing the basic skills that you need to build you own solar panels.