A solar panel is a collection of solar cells, arranged in various configurations to get various wattages or voltages out of the solar cell.
Each solar panel can range from less than 1W up to 250W or greater. It all depends on the manufacturer, and configuration of solar panel bought, which should be bought according to the application. For example, if a solar panel to charge a phone in remote locations is desired, a 100W solar panel wouldn’t really be the best option, whereas a 1W or so would be more suited to the application.
Solar panels provide raw electricity. A solar panel by itself cannot store the electricity that is generated, so unless it’s hooked up to a battery of some sort, the electricity that is always being created when light hits it is being lost. If this energy isn’t considered properly (ie. grounded somewhere) when storing the solar panel, a natural buildup of electricity can occur within the panel which can lead to degradation of the panel because of electrical sparks or arching. When dealing with solar panels, and electricity in general, you don’t want this, so be sure to understand proper handling and storage techniques. The best bet is to talk to the sales rep when buying it. However, with smaller panels it’s usually not even considered a hazard, which isn’t safe to rely on.
So, typically a battery will be what actually powers whatever is being powered, and the panel will charge the battery when there is ambient lighting. The way it works is during the day when there is ambient lighting, each solar cell will create an electrical current that then goes through a control circuit to ensure proper charging of the battery, and then trickles into the battery charging it. There will then be a control circuit (it may be the same as the one from the solar panel) to plug the device requiring power in to. The figure below shows how this is set up, in a very simple format.
Pretty simple isn’t it?
Typically, solar panels should be used by anybody using electronic devices. However, they’ve been really marketed for people to have the convenience of a device to recharge cell phones, iPods, laptops, lamps, or anything else one takes with them into the outdoors is very attractive, so they are widely used by outdoor enthusiasts.
Larger scale applications are most common for cabins off the grid, too far away from any kind of power line. However, there is a large increase in usage within city limits around the world as well, which is a very positive fact considering their power is nearly 100% clean, ignoring construction. Installing solar panels onto a roof is a very practical way to generate a households own electricity requirements, and in some cases it’s even an option to feed excess power back into the cities electric grid. If you’re looking at this type of application, it would really be worth your time to look into the electric companies policy on this, as most will pay you for the electricity generated.
So, keep in mind that the solar panel is really no good unless a battery or electricity storage device is also used directly with it. Sometimes the solar panel will come as a complete kit, with relays, control circuits, plug ins, battery, and of course the panels and directions for safe operation which is a really easy way to go, but usually this direction will be more expensive than buying separate parts and putting/fitting it all together yourself.
If you’re looking at buying a solar panel for your device, be sure to check first what kind of power the device requires. This is usually located on the power adapter, or close to where the power cable plugs into the device. Also keep in mind how many devices are going to be charged in a typical day of the solar panel.
Often times it’s too complicated and just not available to get the information on charging times of electronic devices, but if it is, a quick calculation of the amount of wattage or amp/hours required to charge the devices should be made, and a battery that is capable of producing this should be chosen.
I also want to stress the importance of understanding what one is doing with the solar panel. Make sure to read owners manuals, installation instructions, and any other how-to or information articles on using solar panels if you’re not familiar with electricity. It can be dangerous if not handled properly.
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