LED using Solar Panel

[Maber]

My professor ask me to do a mini project, that will benefit the classroom that we use. And long story short, I came up with an idea to light some dark parts of the room using LED lights with Solar panel as the power source. 

 

The main goal of this project is to help us learn the basics on how to use solar panels.

 

I found this guide online >http://www.instructables.com/id/BUILD-A-NOCTURNAL-SOLAR-LIGHT-BULB/?ALLSTEPS< . 

And I was wondering If I could use a multiple LED with this setup ?

What should I change If say I want to use 6 LEDs ?

 

Please treat me as a beginner when explaining things.

Thanks.

[W-L]

8 minutes ago, Maber said:

My professor ask me to do a mini project, that will benefit the classroom that we use. And long story short, I came up with an idea to light some dark parts of the room using LED lights with Solar panel as the power source. 

 

The main goal of this project is to help us learn the basics on how to use solar panels.

 

I found this guide online >http://www.instructables.com/id/BUILD-A-NOCTURNAL-SOLAR-LIGHT-BULB/?ALLSTEPS< . 

And I was wondering If I could use a multiple LED with this setup ?

What should I change If say I want to use 6 LEDs ?

 

Please treat me as a beginner when explaining things.

Thanks.

 

Yes looking at that it will allow you to put multiple LED's in parallel to have more lights however it will drain the batteries faster of course since it will draw a higher amperage. In the PDF there you can see in typical applications where they have two in parallel to provide more brightness. 

 

-Moved to Hobby Electronics- 

[dany_boy]

Looking at the datasheet you need to adjust the inductor value to accomodate for the extra LEDs. Since this is one of those Chinese ACICs the datasheet is not exactly very professional. Luckily they provide this rather useful chart:

Considering each LED (typical white 5mm) consumes about 20mA in full brightness, then 6 LEDs would require a 33uH inductor to operate at almost full brightness.

Cheers

[mariushm]

You can connect leds in series or in parallel  ... when in series, the minimum voltage required to turn on the leds goes up but the current remains the same.  In parallel, the voltage remains the same but current goes up.

 

It's generally more efficient to wire leds in series, because you lose a lot of energy otherwise in individual resistors to limit the current going through each led.

There are all kinds of led driver ICs and you can find cheap ready made "boost" led drivers on eBay which take voltage from a battery and raise it as much as needed to light up several leds in series.

If you want to make your own circuit, you can buy the separate parts required to build such a circuit from online distributors like Farnell or Digikey (Farnell may be better for you in Philippines).

Here's a link : http://ph.element14.com/led-drivers

Choose one that can work in "boost" mode if you want it to raise voltage from something low (1.5-4.2v  for example) to higher voltages required to turn on multiple leds in series.

For pretty much all the chips on that website, you can download the datasheet where they show example circuits and how to determine the other parts required (inductor size for a particular amount of current) and so on.

You can also find chips that can charge battery from various sources : http://ph.element14.com/battery-charger-ics?searchRef=SearchLookAhead

or you could even go overboard and use some expensive overkill chips specialized for energy harvesting, for taking as much energy as possible from solar cells to charge battery: http://www.linear.com/parametric/energy_harvesting#!cols_1031,2200,1112,1646,2167,1367,1033,1032!s_0,0!gtd_!2200_Solar

 

[Maber]

Thanks for the info guys. 

 

Is 2V enough for the solar panel, since I'll be connecting them in parallel ?

 

 

Sorry for my late reply been pretty busy at school lately.

 

Edit: if i want another power source, besides the solar panel. Can I use a cellphone charger ? If yes, do I just have to connect them the same connection as the battery?

Edited December 16, 2016 by Maber