PV Gap

Ricky Said:

how to design a solar panel to store energy and convert it into electrical energy?

We Answered:

solar panels change light into electricity, and do NOT store power.

You need a solar panel capable of enough power to keep the light on all night. And that may be 6 hours of sun and 12 hours of dark.

Then you need a set of batteries large enough to hold that energy. And a charge controller to regulate the charge into the batteries. And then a light that will operate on the battery voltage, say 12 volts.

This is probably not practical due to the large solar panel required, and the large batteries. But here is a few numbers. Assume a 100 watt light at 12 volts. Assume you get at least 6 hours of sun every day and the light will be on for 12 hours. That means the battery has to store 100*12=1200 watt hours. divide by 12 and that is 100 amp-hours, a large auto battery size.

Allowing for 20% losses in the battery and circuitry, that means you nee 1400 watt hours from the solar panel. Since it has 4 hours to operate, that means it has to deliver 1400/4 = 350 watts at 15 volts.

So there it is: 350 watt panel
100 amp hour battery
charge controller sized for above
100 watt light.

If you have to allow for a day with no sun, then you need more batteries. Two nights means 2400 watt-hours, two batteries, a larger charge controller and a 2800/4 = 700 watt panel.

cost: $400 for batteries
$200 for charge controller
$2000 for panel

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Hilda Said:

simple definition of how a solar panel works?

We Answered:

Sunlight (photons) hit a piece of silicon and knock electrons out of it. That causes a flow of electrons, which is electrical current.

simple enough?

a better explanation from wikipedia:
A solar cell is a device that converts the energy of sunlight directly into electricity by the photovoltaic effect. Sometimes the term solar cell is reserved for devices intended specifically to capture energy from sunlight such as solar panels and solar cells, while the term photovoltaic cell is used when the light source is unspecified. Assemblies of cells are used to make solar panels, solar modules, or photovoltaic arrays. Photovoltaics is the field of technology and research related to the application of solar cells in producing electricity for practical use. The energy generated this way is an example of solar energy (also known as solar power).

Simple explanation
1. Photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon.
2. Electrons (negatively charged) are knocked loose from their atoms, allowing them to flow through the material to produce electricity. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction.
3. An array of solar cells converts solar energy into a usable amount of direct current (DC) electricity.

Solar cells are often electrically connected and encapsulated as a module. Photovoltaic modules often have a sheet of glass on the front (sun up) side, allowing light to pass while protecting the semiconductor wafers from the elements (rain, hail, etc.). Solar cells are also usually connected in series in modules, creating an additive voltage. Connecting cells in parallel will yield a higher current. Modules are then interconnected, in series or parallel, or both, to create an array with the desired peak DC voltage and current.

The power output of a solar array is measured in watts or kilowatts. In order to calculate the typical energy needs of the application, a measurement in watt-hours, kilowatt-hours or kilowatt-hours per day is often used. A common rule of thumb is that average power is equal to 20% of peak power, so that each peak kilowatt of solar array output power corresponds to energy production of 4.8 kWh per day (24 hours x 1 kW x 20% = 4.8 kWh)

To make practical use of the solar-generated energy, the electricity is most often fed into the electricity grid using inverters (grid-connected photovoltaic systems); in stand-alone systems, batteries are used to store the energy that is not needed immediately.

Solar cells can also be applied to other electronics devices to make it self-power sustainable in the sun. There are solar cell phone chargers, solar bike light and solar camping lanterns that people can adopt for daily use.


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Raymond Said:

What materials would I need to create a working solar panel out of aluminium cans?

We Answered:

could you give the name of the show?
I can see how a solar powered steam engine could be made from those items, then connected to a generator to make electricity. But not photosynthesis.
I could be wrong -- post the link

Natalie Said:

How does a solar panel work?

We Answered:

"A solar panel is a collection of solar cells. Lots of small solar cells spread over a large area can work together to provide enough power to be useful. The more light that hits a cell, the more electricity it produces".

"A solar cell or photovoltaic cell is a device that converts light energy into electrical energy by the photovoltaic effect."

Jerome Said:

Can I get my laundry room working on solar energy alone?

We Answered:

If your washer is a front load, and you switch your dryer to a small plastic lined closet with a small dehumidifier, it would save its cost in reduced solar panel and battery cost.

But you do not need to have capacity to run both washer and drier at one time, just the larger load.
(That is why you need to change to a small dehumidifier in a plastic lined closet... a clothes dryer demands so much power).
Front load washers will cut your electrical load directly, but also cut the amount of water left in the laundry, so less drying energy needed.

My system has a starting load of 400 watts, so I need a battery pack to provide that much starting load, but my continuous load is 220 watt.

Now this is supported almost entirely by a battery array and a 540 watt inverter that converts 12 volt to 120v 60 Hz.
One load of washing uses 250 watt hours(Up to 300), and drying takes about 500 watt hours.

Using a top load washer might use 500 watt hours, but would also demand more current. Using a clothes drier would be unthinkable.

If you use the system more frequently with smaller amounts of power needed per usage, it cuts down the amount of battery power you need. That is why you want to cut down your energy need to a minimum.

A battery is sold with a number of ampere hours.
When you look for more watts, remember to multiply ampere hours by 12 to get watt hours, so that a 100 ampere hour battery will store 1200 watt hours of power. One large deep discharge battery is enough to wash and dry a load of laundry (or almost dry it) depending on how much sun power you are collecting.

If you want to recharge that 100 amp hour deep discharge battery for use next day, you need to have enough solar panels to deliver 100 ampere hours of power per average winter day. (1200 watt hours)
This map will give a hint as to the amount of rated capacity you will need.
http://www.solarcraft.net/sun-hours-map.…

For battery charging you also need a voltage regulator.