Some questions about solar-powered LED

xela

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I am going to construct a solar-powered LED lamp. I am a newbie in this topic. As I know here are many professionals and may I ask some questions here?

Here is my idea:
solar panel->voltage shunt charger->rechargable battery->RGB LED driver->RGB LEDs

and here are my problems and questions:
1)How much power should the solar panel generate to have about 800 lumens at LEDs?
2)What exactly is a RGB LED driver and are there any commonly used in this topic?(not expected to use a microconcontroller)

thank you for yr attention
 

simonsays

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Ummmm. 800 lumens is pretty bright for an LED setup
rolleye11.gif


This is -one- way of getting 800 lumens
http://elektrolumens.com/K2-Stunner/K2-Stunner.html

I dont know how you'd go about making a solar powered version though. Wayne recommends 12000mAh rechargable D cells to power his 'big' torches and they take quite some time to charge up (24 hours+ in my charger). I suspect you're going to need lots and lots of solar cells/sunshine for the project you have in mind.

More knowledgeable members than me may well be along shortly with better ideas. Good luck
smile.gif


Simon

Oh, and welcome to cpf. Hang on to your wallet:laughing:
 
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xela

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thank's for yr advice
actually those are only my assumptions
um...how bright should it be if it's just considered as a desk lamp?
or say, how many sets of RGB LED should be used?
 

Calina

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At 20mA you should get between 2.5 and 4 Lumens per 5mm LEDs; so with 5 LEDs you will have between 12.5 and 20 L. If you over drive the LEDs at 30mA you could get up to 6 L with good Leds. That should be enough for a desk lamp. If not you can add more LED later but more leds could mean a bigger solar panel or longer charge time. Don't forget, LEDs are more efficient (more lumens per units of energy consumed) at lower current, 20 mA is a good compromise.

The size of the solar panel will also depend on the autonomy you require from your batteries.

See this Thread for more information: http://candlepowerforums.com/vb/showthread.php?t=89607

As for the rest of your project I will leave the opportunity to answer to somebody else .

Good luck and welcome to CPF.
Have fun.
 

Illum

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the amount of solar cells to use with regulated drivers will make it impossible for edc...:laughing:

solar cells arent really that efficient in terms of footprint....solarcells give out a higher voltage and lower current:awman:

xela said:
solar panel->voltage shunt charger->rechargable battery->RGB LED driver->RGB LEDs

you must put concern on the circuitry resistance...the more stuff you add, the longer the electrical path is...:ohgeez::huh:


its a good idea, i dont blame you for the idea, in fact when I first got here i posted the same thing, so far I havent seen a solar powered light that works over 3 seconds at full brightness:ohgeez:
 

Calina

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It could work, don't despair and don't listen to people who say otherwise.

Look at the solar garden lights - it works. You just need bigger cells.
A 2 to 5W panel should probably do the job if you don't need light for more than a couple of hours a day.
 

xela

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To tell the truth
this is a project for me, a electronic student
there are some confusion. My superviser told me to use RGB driver(?) to driver RGB LEDs instead of white LEDs.
and also LED requires about 10mA and 3V each to turn on? He told the other story....
 

Calina

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xela said:
To tell the truth
this is a project for me, a electronic student
there are some confusion. My superviser told me to use RGB driver(?) to driver RGB LEDs instead of white LEDs.
and also LED requires about 10mA and 3V each to turn on? He told the other story....


I guess you'll have to talk to you supervisor. Why RGB?

LED do turn on at much less than 10mA and 3V. They can work at extremely low levels (albeit with very little light output), have a look at the PAL light for an idea.
 
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