NEWBIE QUESTION (parallel led)

Djatnet

Newly Enlightened
Joined
Jun 4, 2008
Messages
4
Hi, i'm new at this kind of electronics and i would like to ask you something.

What kind of driver should i use in this application?

ledcopydq8.jpg


In this case i would have +/- 3.6v and since i'm using rechargeable battries of 2500mAh in parallel i still have the same 2500mAh "Theoretically". (I'm from Portugal and i must use this kind of battery because it is the most usual in the market)

I already made that kind of aplication but with some changes I used 3+3 batteries to change from 2500mAh to 5000mAh and no driver. What kind of advantages and disavantages can i get with the driver?

Thanks.
 
Last edited:

TorchBoy

Flashlight Enthusiast
Joined
Jan 15, 2007
Messages
4,486
Location
New Zealand
Re: Parallel LEDs

:welcome:

If you put the three cells in series you would have 3.6 V and 2500 mAh capacity. With them in parallel like in your drawing you have 1.2 V and 7500 mAh.

You also have drawn the three LEDs in parallel, which is not the best way to do it, because if they have different operating voltages then they will draw different current. If the LEDs' operating voltages are quite close then it will work, perhaps a bit unevenly.

What current do you want to run each LED at?
 

LukeA

Flashlight Enthusiast
Joined
Jun 3, 2007
Messages
4,399
Location
near Pittsburgh
Re: Parallel LEDs

The way I would do it would be to use 3 separate AMC7135 drivers (they're cheap enough to do this), put those three cells in series and run the three drivers in parallel and have each run a single LED.
 
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