Need Power Supply Help from the guru's.....(you know who you are)

[ezimnow]

Just want to be sure I have this configured right...I probably don't and I don't want to burn out my pixels if I made an error...

 

I have 12 WS2811 IP68 12v pixel (50 cnt)connected to a ECGP-12R. I string per bank

 

Power  supplies are 2 12v 360W...

 

Math 0.3 watts per  string *50 12v

3amps per string= 36A

= 432 Watts?

 

So I would hook up one 12V power supply per side on the Controller?

 

 

 

Thanks

Eddie Z

[Crazydave]

Each Pixel uses 0.3 Watts 

50 Pixels per string = 0.3 watts * 50 pixels  = 15 Watts per string  or 1.25 Amps per string

15 watts * 12 strings = 180 watts

 

now factor in some head room... run it at 80% of rated capacity.

 

180/80% = 180/0.8  = 225 watts

 

You should be able to run one (1) 350w power supply.

Edited June 11, 2014 by Crazydave

[Ron Boyd]

Just to add to what Crazydave said, I ran 16 strings of 50 pixels each plus 210 Basic nodes from the same 350W, 60A power supply last year. No problems

Edited June 11, 2014 by Ron Boyd

[ezimnow]

Ok, and of course I have to use a 12V Power supply for the 12V pixels and if I had 5V pixels  I would  go with a 5V power supply? Seems basic but I have to ask.

[ezimnow]

By the way, thank you both Crazydave and Ron...

[Ron Boyd]

You are correct. Match the PS voltage to the Pixel voltage, and you're welcome.

[Max-Paul]

Crazy,

 

.3W is that for just one color or all 3 on at the same time? Did some quick math and I see .02mA per color. And now times 3 colors and I got .06A. And now if we do PIE for power its 12V X .06mA = .72W. Just for the kicks of it I did the same with 5V and then I came up with .3W.

 

So using my .72W per pixel times 50, I see 36W and times that by 12 I see 432 Watts.  I think you confused yourself and used data based on a 5V Strips.

 

OP I would say that putting one P.S. per bank (side) is a great idea.

[Ron Boyd]

I agree with Max.

 

Using 12v pixels, I came up with 432w also. I went about it a different way, but came up with the same numbers. I used Holiday Coro 12v pixels as a reference. David publishes the Watts and Amps in his descriptions on the web page.

 

Mine were 5v pixels which comes up to 240 Watts and 48 Amps. The dumb (basic) nodes came up to about 50 watts and 4.2 amps. I actually ran my power supply at about 82%. I know that's  2% over the rule of thumb of 80%, but I didn't have any dim pixels.

[plasmadrive]

Max,

Your numbers would  be good for single LED pixels  but that would change if he is using the 12v strings that have 3 pixels in series to allow for the 12v. (he doesn't say which he is using)

 

Still .06a per pixel at full white but with three in series there would be something other than 50 pixels on a string I believe. 51 perhaps?  That would mean 17 "pixels" If the above happens to be the case then the total wattage would be about 1/3.

[ezimnow]

For the sake of working out your power requirements you can assume a working current of 60mA per pixel (55mA is probably closer to theoretical and 50mA is what is actually likely unless you have awesome power injection). The 60mA doesn't matter if it's at 5V or 12V as the pixels are constant current typically and the extra volts goes into heat. Using that you get 12V x 0.060A which gives 0.72W per pixel or 36W per string of 50 or a total wattage of 432W. With voltage losses (and the fact that the calculations were done at 60mA) you are likely to be well under 400W.
  As far as pixels per output you are certainly under doing what the P12 is capable of. You can happily put 3 strings on an output or if you were using a P2 you could have all 600 pixels on the 1 output and leave 1 free.

[ezimnow]

These are the Pixels I am using

http://www.diyledexpress.com/index.php?main_page=product_info&cPath=42_44&products_id=189

 

 

The post above was from the Aussie chat..

[ezimnow]

Thats why I opened this Topic as I got confused as to what I needed. I didn't think and still don't think I know how you guys are figuring out the actual power needs and then when you say your running your PS at a certain %...man, that confuses me more. How do you adjust your PS....is it a certain type that you can do that to?

 

My main concern is that I don't want to blow out the pixels and when I did the math I was thinking I needed to have 1 PS per side. From what Ron and Crazy Dave are saying they only use 1 PS but It will make a difference based ont the Pixels each of us use?

 

Max kind of agrees with me...I think (LOL)

 

I posted the link to the Pixels I'm using so hopefully that clears it up....I apologize for any confusion...

 

Eddie Z

[CLD Kevin]

The percentage that was mention is no adjustment setting on the power supply. Its a rule that many of us use. Its called the 80% Rule...meaning run the power supply at 80% of the max it can handle. So if your using a 360W PS, the max power you want to drive it is 228W. This is so you don't overdrive the PS and burn it up. I run at 80 - 85%.

Go with 2 PS for the 12 50ct strings (432W). 80% of the 2 PS would be 576W....more than enough plus extra for future.

Distance, injection, ect are other factors to consider. If using in close proximity like for a single mega tree, probably don't have to inject power down the line from a separate power source.

[plasmadrive]

who started this 80% thing anyway?  Most good power supplies will run at full power without issue as long as you don't try to run them where they can't cool themselves.  I agree there is nothing wrong with chosing 80% as a safety factor, but for good supplies it is not so necessary..

[ezimnow]

Thanks for clearing the air on the 80% PS rule Kevin. Glad I posted this topic and gratefull to all for their input...now its time to put it all together...

 

Thanks Again!!!!

 

Eddie Z

[Crazydave]

80% for line losses, etc

[Crazydave]

Crazy,

 

.3W is that for just one color or all 3 on at the same time? Did some quick math and I see .02mA per color. And now times 3 colors and I got .06A. And now if we do PIE for power its 12V X .06mA = .72W. Just for the kicks of it I did the same with 5V and then I came up with .3W.

 

 

 

If it says 0.3w   I'd assume 100% white is going to use 0.3 watts

 

 

There is some confusion.

 

I looked at Holiday Coro's website:

 

They claim

WS2811 Pixel node is 60mA for 100% White.

at 12v this would be 0.72 watts

at   5v this would be 0.30 watts

 

but their website says:

• Power
  • 12v DC Input
  • White (all three colors) per node: 60 miliamps / .3 Watts
  • White (all three colors) per string (50 nodes): 3 amps / 36 Watts

 

 

60 mA does not equal 0.3 watts at 12v..... it equals 0.72watts

 

 

however.... 60mA * 12 V * 50 pixels does equal 36 watts.

 

 

Not sure which spec is correct....

 

 

 

Now for the 12v 2801 pixels

Power

• 12v DC
   
• White (all three colors) Single Node: ~36ma
• White (all three colors) 100 Nodes: 3.6 amps / ~44 Watts\

it's slightly different.

 

not sure why.

Edited June 13, 2014 by Crazydave

[Max-Paul]

Max,

Your numbers would  be good for single LED pixels  but that would change if he is using the 12v strings that have 3 pixels in series to allow for the 12v. (he doesn't say which he is using)

 

Still .06a per pixel at full white but with three in series there would be something other than 50 pixels on a string I believe. 51 perhaps?  That would mean 17 "pixels" If the above happens to be the case then the total wattage would be about 1/3.

Say what, Plasma?  be it one or 100 in series. It is still 20mA. And in the case of 12V and one LED. Then there would be a currently limiting resistor so that only 20mA would flow in the circuit. But because this is RGB (3 LEDS in a single package). then we need to say that this would draw 60ma per node or pixel. Now if the node or pixel is made up of 3 RGB LEDs, it is still 60mA. My numbers are good anyway you slice it or dice it.

[plasmadrive]

yes.. and no.  Current in a series circuit is the same.. it is about 20ma per color... you still have drop on the LEDs and you have to have enough voltage available to allow you to draw the needed current.. But you can put 100 LEDs in series and if you have enough voltage.. they will all draw the 20ma if you have your current limit set as such..  so 20ma per LED junction.. regardless of the voltage.. my point is that there are only so many LEDs on a strip.. so the power per strip would be what changes.. 

[Max-Paul]

Crazy,

 

I really do not know how to answer what the site says. But I am 55, and have been doing electronics for the past 40 years. Ohms law is just that a law. And PIE has never failed me in pure D.C. circuits. So to find power, one multiply voltage by current (P=I*E). And we know that the 5050 RGB module is rated for 20mA per LED. Remember we are looking for max power required of the power supply. So, thus I have all 3 LEDs turned on and drawing max current of 60mA.  So, using the above formula we take 12 * .06A = .72W * 50 = 36w per string.

 

Sorry to all of my friends. But all other answers are wrong.  I do not know where ezimnow comes up with this 55 or 50mA. Now that might be where you run it or after the voltage drop it might end up there. But I am going strickly by what it is rated for. Not some magical might be cause of this or that variable.