How many GGG LEDs can I wire together when connected to the PC's 5V power?

[unclet]

I would like to wire some of Randy's LED lights directly to my PC's 5V/ground power supply connectors.  How many of these GGG LED lights can I wire together and still have them work?

(EDIT)
All LED lights will be wired in parallel ....

[Franco B]

Depends on the LED forward voltage, the LED forward current and how you wire them

I think you will get more if you wire the LEDs in parallel.

This is a handy link that will work out an array for you and also tell you what resistors to use.

http://led.linear1.org/led.wiz

Put the values of the resistor in and then just keep increasing the resistor count until you cannot add any more.

[unclet]

That link you provided me is way over my head.   Pretend I have absolutely no knowledge of electricity.   

Now, I am using the resistors which Randy includes with the GGG LED lights and I am wiring them in parallel.

Perhaps someone can tell me how many can be connected together using one set of 5V/ground lines from the PC.

[Neverending Project]

I was in the middle of writing a reply when Franco B beat me to it. 

Another thing to consider is the USB bus itself. The USB bus allocates current in 100mA units, up to 500mA per port. Most places you plug your USB cable into in your PC will actually be a hub (even the front USB access in your PC is usually an intenral hub), and hence will most likely only be able to pull between 100mA and 500mA. If you plug your USB cable into a self-powered hub, it may depend on the total current rating of the hub itself.

Unfortunately, it will be a bit of a trial and error for you. Each USB device will be different, and other devices on the same bus will be drawing current also. As a general starting point, I calculated that you should be able to get 5 LEDS in parallel with a 100Ohm resistor each, and this will draw about 100mA.

FWIW, if you are talking about the ButtonBlaster LEDs from GGG, according to his site they have a drop of 3.0-3.5V (most LEDs like this are around 3.3V) and draw 20mA current each.

Hope this helps.

[EDIT] Hold on a minute here... I somehow thought you wanted to connect them to the 5V in a USB bus, but now I realize that you are talking about the 5V power supply. In this case, it depends on how much current your power supply can dish out (taking into account the rest of the 5V circuitry on your computer that also needs that current). Sorry for the mis-info above.

[RetroACTIVE]

That link you provided me is way over my head.   Pretend I have absolutely no knowledge of electricity.   

Now, I am using the resistors which Randy includes with the GGG LED lights and I am wiring them in parallel.

Perhaps someone can tell me how many can be connected together using one set of 5V/ground lines from the PC.

(current) X (voltage) = power ... example: 20mA over 5 volts = 0.1 Watt per led

[Havok]

Depending on the psu, more than you will need...

[Neverending Project]

How many do you want to use? I have read some info here and there that suggests you don't want to wire too many in parallel, they don't share current very well. What some people have done is make legs of a few in series, and then wire these legs in parallel - so you have a combination of parallel and series.

But in your case, you wouldn't be able to do this unless you used the 12V supply, and hence could put 3 in series (with a 120Ohm resistor). Then if you put 10 of these legs in parallel, you would have 30 LEDs.

In fact I just checked using the calculator link provided above, and if you enter 12V as your source, 3.3V and 20mA as the LED voltage and current, it will actually build you a circuit with 10 legs of 3 LEDs each, complete with resistor values and how to hook them up.

[unclet]

I thought it would be a simple answer.   I know nothing about electricity so I have no idea how many volts or amps or mA stuff means.   Lets assume the power supply is 200Watt.   I would like to connect 8 LED lights in parallel only.

Do you think this would work?  If not, then I guess I just will think of something else.   

 

[Neverending Project]

I thought it would be a simple answer.   I know nothing about electricity so I have no idea how many volts or amps or mA stuff means.   Lets assume the power supply is 200Watt.   I would like to connect 8 LED lights in parallel only.

Do you think this would work?  If not, then I guess I just will think of something else.   

 

Yes. Hook them up like the attached picture.

[unclet]

Excellent .....  thanks for the effort.    

It seems I can simply wire the LEDs in parallel like your diagram .... that is great.

I am assuming you know Randy's resistors are 100 ohms?   I mean I have no idea, but I will take your word for it.   

Thanks again.   

[Neverending Project]

I am assuming you know Randy's resistors are 100 ohms?   I mean I have no idea, but I will take your word for it.   

Actually, no. I don't know this. This picture is from the afore mentioned calculator (wizard?), and it calculates the resistor size based on the number of LEDs and their current draw. Considering Randy states that it includes an "appropriate resistor for a 5V connection", I would assume it is correct. But if it isn't, and he cannot substitute for the 100 Ohms, they are very easy to find and readily available most everywhere resistors are sold.

Good luck!

[urbecrisch]

unclet, please post your results.  I'm thinking of doing the same thing with my PC.

[Fozzy The Bear]

unclet, please post your results.  I'm thinking of doing the same thing with my PC.

Don't worry!! Just go ahead and follow the information supplied there by "neverending project" It is correct......

As for the resistors supplied by Randy with the LED's don't worry! They're fine in this application and are exactly matched to the current draw of the LED's that Randy supplies! Just go ahead and use them.

Best Regards,
Julian (Fozzy The Bear)

[unclet]

urbecrisch
When the project is done there will be pictures of everything

Fozzy
Excellent .... thanks

[Zebidee]

When wiring many LEDs together, you may be better doing it in series, and running it from the PC's 12v rail.  This should result in less stress on the 5v rail and less heat buildup.  Each LED subtracts it's forward voltage from the line, so 12v could easily power 3 x 3.5v LEDs (= 10.5v) running in series behind a single resistor (rather than one per LED).  If you want more than 3 LEDs, then wire another set of them + resistor, in parallel with the first set.  Each set of LEDs in wired in series, but each set in parallel with each other.

If you want just one or two LEDs, then powering from 5v is fine.

[Green Giant]

Well, a simple answer for you.

I have about 51 hooked up through 2 ledwiz's.  All the power comes off a single 5V wire from the computer power supply.  It can probably handle many more since those power supplies are designed to run hdd's and dvd drives, bigger current draws.

[ivwshane]

Well, a simple answer for you.

I have about 51 hooked up through 2 ledwiz's.  All the power comes off a single 5V wire from the computer power supply.  It can probably handle many more since those power supplies are designed to run hdd's and dvd drives, bigger current draws.

Are you having any issues with controlling the various leds with two ledwiz's? I was looking to do the same and my project would require two ledwiz'a but a disclaimer on ggg's website seems to indicate that there are some issues with various front ends when using more than one.


Also can you post a pic on how you connected them to your ps?