Initiation: DIY a pilot light

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Boris591
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Registration: 26/04/08, 13:39

Initiation: DIY a pilot light




by Boris591 » 26/04/08, 13:44

Hello

I'm slowly discovering renewable energy (an area that interests me a lot)

and I would like to start making very simple DIY.

First assembly I want to make: a stand-alone bulb.

The idea is simple: a solar panel that charges a battery during the day, which in turn will power the bulb throughout the night.


That said here is my question: the assembly will be carried out with an ordinary 100 w bulb.

How to calculate your energy need for around 12 hours, essential for choosing a sufficiently powerful battery, and a solar panel capable of charging it in 12 hours too.



thank you for giving me the basic formulas which will allow me to calculate this simple data myself :P
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nlc
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by nlc » 27/04/08, 01:10

A 100W bulb will have consumed 100Wh of energy after 1h, so will have consumed 1200Wh after 12h.

So you need a 1200Wh energy reserve to light your 100W bulb for 12h.
If your bulb is a 12 volt bulb, your energy tank can be a 12V battery.

A 100W / 12V bulb consumes 8.3 Amperes (P = U x I therefore I = P / U)
So after an hour she will have consumed 8.3Ah. To last 12 hours, your battery must therefore have a capacity of 8.3Ax12h = 100Ah.

We arrive at the same result by knowing the energy reserve you need (1200Wh), and dividing it by the voltage of your tank. So 1200Wh / 12V = 100Ah.

So your battery must be a 12V / 100Ah battery so that it can light your 100W bulb for 12 hours.

So you need a solar panel that can fill this 12V / 100Ah (1200Wh) tank during the day. If we consider that we have 8 hours of sunshine during the day, your panel must be able to supply 150W for 8 hours. Which makes us good 150W x 8h = 1200Wh.

In theory you would need between 1 and 2m² of solar panel. In practice probably between 2 and 3, because it is not said that there is really 8 hours of sun.
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nlc
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by nlc » 27/04/08, 01:12

Note that by using LED bulbs, there is a way to have the same amount of light as a 100W bulb but with a lower current consumption. So necessarily a lower energy reserve, and a lower panel surface
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Boris591
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by Boris591 » 27/04/08, 10:46

thank you very much nlc

perfect answer :P

I will be able to do my little calculations now :)

thanks a lot
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Boris591
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by Boris591 » 27/04/08, 11:11

nlc wrote:Note that by using LED bulbs, there is a way to have the same amount of light as a 100W bulb but with a lower current consumption. So necessarily a lower energy reserve, and a lower panel surface



I thought about it too.

On this site I see 12 or 1 w 3v leds

But in terms of clarification, they are comparable to "traditional" bulbs of how many w? 15? 50? ....


please :P
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Obelix
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by Obelix » 27/04/08, 11:51

Hello,

Already a compact fluorescent bulb would divide by three the power needed for the same lighting.
Then for the sizing of the solar panels, we must take precautions because 8 hours a day seems super optimistic !!
By experience I take 3 times the peak power of the panel used per day. And I am very close to the actual measures. And again I am in the region of Toulon !!!

For the example cited I would take 400Wp of panels which leads to a 12 volt battery of 400/12 => 34A of charging current, ie a 350 Ah battery.
This by experience because I participate in the maintenance of an isolated site which consumes 1 kWh / day approximately 24/24 7/7.

Obelix
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Boris591
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Registration: 26/04/08, 13:39




by Boris591 » 27/04/08, 23:25

thank you for this additional information

that allows me to refine my project a little
(and I learn interesting things :P )



I have another question :
a quick search on the batteries, and I find that 12 v.

or for some DIY idea, I will have to use 220 (for a fairly powerful electric motor)

I know that it "suffices" to convert the 12 to 220, but is there no loss in the maneuver? I'm talking both in terms of power and battery charge capacity (well, won't that reduce the maximum possible time of use of the engine?)


thank you :)
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rodibruno
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Re: Initiation: DIY a pilot light




by rodibruno » 28/04/08, 00:36

Boris591 wrote:Hello

I'm slowly discovering renewable energy (an area that interests me a lot)

and I would like to start making very simple DIY.

First assembly I want to make: a stand-alone bulb.

The idea is simple: a solar panel that charges a battery during the day, which in turn will power the bulb throughout the night.


That said here is my question: the assembly will be carried out with an ordinary 100 w bulb.

How to calculate your energy need for around 12 hours, essential for choosing a sufficiently powerful battery, and a solar panel capable of charging it in 12 hours too.



thank you for giving me the basic formulas which will allow me to calculate this simple data myself :P



A friend :
a consultation pages that:
http://www.coolearthsolar.com/
Image

they say they increase the capacity of the photovoltaic panels a lot, it's a simple and very easy solution to compete, by ejemp`lo an old parabolic screen and aluminum foil, they could replace this reflector.
A type!!
Greetings from Argentina

Rodolfo
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