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in need of a certain solar cells for my project

nkey292

Mar 26, 2014
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hello dear friends,

i am new at solar and Photovoltaic energy and would like to find some solar cells adapted to my application ,
i need a current of 0.5Amps with a voltage of 5 volt and as small as possible ( for the current and voltage the serie and parallel associations can solve the problem ) what i need exaclty is the dimensions to be as small as possbile
thanks you guys :)
 

Gryd3

Jun 25, 2014
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Please remember that the rated output for many panels is in direct sunlight.
Keep this in mind when designing the circuit and de-rate the panels you plan to use to ensure you have a sufficient source to power your circuit.
Depending on your application, buying from EBay or ripping them out of other electronics are the way to go.

What kind of sizes are you limited to? A couple sources online indicate at least 11 Watts / Sq Ft of panel. Using this number alone, you'll need a 6"x6" Square panel (Or equivalent dimensions).

Will you circuit only be on only during peak performance of the panel, or will it be running for extended periods of time?
You may need a larger panel to charge a battery to power the device during cloud-cover or dips in light as the device is running. You may need a larger panel to compensate for the conditioning of the power provided by the panel. You may not be able to make it as small as you want..
 

nkey292

Mar 26, 2014
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yes #Gryd3 you are right , but what i have in mind is that i will use an intern battery , that will as long as the panels are exposed to any source of light , store the enery that we will use when we'll need it, so the most important thing now , is the power , because the bigger the power the shorter this battery will charge
thank you a lot , but i need some references , because i have many applications , so i am not in need of just one solar panel , but a lot , so i am gonna need to buy them , not take them from electronics
 

Gryd3

Jun 25, 2014
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yes #Gryd3 you are right , but what i have in mind is that i will use an intern battery , that will as long as the panels are exposed to any source of light , store the enery that we will use when we'll need it, so the most important thing now , is the power , because the bigger the power the shorter this battery will charge
thank you a lot , but i need some references , because i have many applications , so i am not in need of just one solar panel , but a lot , so i am gonna need to buy them , not take them from electronics

Ok, so from your first post, you have requested a 5V 0.5A Panel.. Chances are you'll have issues find a panel that gives you exactly these numbers.
Look for at least a 2.5Watt Panel. If you are charging a battery for operation during cloud-cover and night, then please average the power requirement for at least a 24 Hour cycle. (2.5 Watts will only provide you with enough juice to provide 150mA at 5V for a 24H period with 8 Hours of ideal sunlight... This would require almost 0 loss in the circuit..)

http://www.digikey.ca/product-detail/en/750-00034/750-00034-ND/2272160
You may very well need to source or build a voltage power supply (most likely Boost type) that will power your circuit and charge the batter.
 

Anon_LG

Jun 24, 2014
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Supercap2F

Mar 22, 2014
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Ebay item number:160968808439 Is a solar cell that measures 13x15cm 5 VDC out 0.5 Amps. Two of them cost about 25 bucks. Looks like what you need.

Dan




Edited $12.59 each
 
Last edited by a moderator:

davenn

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Sep 5, 2009
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Just be aware too that panels are usually rated at open circuit output voltage
They drop substantially when loaded. You may find you need a 10V open Circuit voltage panel

READ THE DATA SHEET CAREFULLY

cheers
Dave
 

Supercap2F

Mar 22, 2014
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Somebody changed what I said. :confused: I really said this:

Ebay item number:160968808439 Is a solar cell that measures 13x15cm 5 VDC out 0.5 Amps. Two of them cost about 13 bucks. Looks like what you need.

Dan

Someone changed it to 25 bucks instead of 13 bucks. Then someone else edited it and said:

Edited $12.59 each

It's really 12.59 for two not one. :D

Dan
 
Last edited:

nkey292

Mar 26, 2014
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Somebody changed what I said. :confused: I really said this:



Someone changed it to 25 bucks instead of 13 bucks. Then someone else edited it and said:



It's really 12.59 for two not one. :D

Dan
lol , i can't do that , if fact i couldn't see the item in ebay , because i have some kind of restriction i don't know why ? can you take me a screenshot of the page please ?
 

Supercap2F

Mar 22, 2014
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I attached a screen shot for you. But just type in the item number in to ebays search engine, and it should bring it up.

Edit: make sure your on the USA version of ebay:)

Dan
 

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nkey292

Mar 26, 2014
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I attached a screen shot for you. But just type in the item number in to ebays search engine, and it should bring it up.

Edit: make sure your on the USA version of ebay:)

Dan
thank you al lot bro, i will take a look on it
 

davenn

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Somebody changed what I said. :confused: I really said this:

Someone changed it to 25 bucks instead of 13 bucks. Then someone else edited it and said:

It's really 12.59 for two not one. :D

Dan

NO read the ebay page again Dan !! look at your own screen dump

Quantity 1 for $12.59

I was the one that edited you post ;)

Dave
 

Supercap2F

Mar 22, 2014
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Untitled.png

Maybe I'm missing something, but the "Get lots" drop down list is set to two and It's still 12.59. Am I looking at this wrong?

Regards

Dan
 

davenn

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maybe I am haha

I give up haha

if some one else can confirm you thought, I will re-edit your earlier post and tidy up the thread
 

davenn

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nkey292 hasn't said what country he is from ... maybe ebay is inaccessible there ??
 

Anon_LG

Jun 24, 2014
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I still want to know about the overcharge preventative system, do you have one?
 

Gryd3

Jun 25, 2014
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I still want to know about the overcharge preventative system, do you have one?
Well, overcharge may not be an issue if the device draws any more than 330mA (Assuming 8 Hour Night, 16 Hour day with 100% efficiency...) Losses will need to be factored in, as well as non-ideal light conditions.
Of course it is always best to side with caution and put protection in... you skimp on that and you can cause some problems.
 
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