Pixel confusion

[~DOC~]

I invested in some pixels and a pixie 16 with power supply. I also bought one of those dumb controls to just see if the pixel string is working. So the power supply is only 1amp at 12 volts (12watts) how in the heck is it lighting 4 stings of nodes on full white. With no issues. The math says it won’t Light the first string? 

I am going to do a check with the fluke meter this week to see what it’s drawing but this has me a little baffled at the moment with out tests since it should be discolored.

[~DOC~]

9 minutes ago, Mr. P said:

I don't know but if you just figure a 50 pixel string at 36w x 16 strings = 576w total. It all comes down to the specs of the lights but with 16 ports I can almost guarantee you will need more then 350w.

Hey Mr P check above statement

[k6ccc]

Something does not add up.  Most common pixels are about 0.060 amps per pixel.  So a 50 pixel string will be about 3 amps.

 

[Mr. P]

Here is a popular ws2811 50 pixel string, read in the description 36w total.

http://www.holidaycoro.com/12mm-Pixel-Node-With-Waterproof-Connections-p/711-wp.htm

[~DOC~]

26 minutes ago, TheDucks said:

Those are 100 node strings. I estimate 96A, over a KW 😮 They did say Meanwell supply with extra cooling in the BOM

I have a power supply that’s 1 amp 12 volts says it does 18watts. It’s running 4 strings of pixels

[~DOC~]

I wish I could figure out these phone pictures. So I can post easily what I have done.

[TheDucks]

1 minute ago, ~DOC~ said:

I have a power supply that’s 1 amp 12 volts says it does 18watts. It’s running 4 strings of pixels

Cheap supplies don't have real good current protection.  1A @ 12V is 12W out. supplies are not 100% efficient, so 18W might be the input (and that is pretty bad efficiency)

[~DOC~]

1 minute ago, TheDucks said:

Cheap supplies don't have real good current protection.  1A @ 12V is 12W out. supplies are not 100% efficient, so 18W might be the input (and that is pretty bad efficiency)

It’s me playing around figuring out things. But hopefully this picture comes through

[~DOC~]

I am using the power supply to control the dumb controler but it’s hooked to 4 strings. For some reason. I cannot compress the picture of the strings hooked up small enough to post. 

[TheDucks]

Yew, the 18W is the input (I also have a few of those SAME from my Network switches, routers) Netgear is Communications equipment. They have a 5Y warrenty, but mainly COM suppliers build for high MTBF because their gear runs 24/7.

Still, that doesn't mean you should abuse them. Great for a short test ( I also have a bunch of 12 3-5A bricks from old LCD panels and stuff)  I also have a old, weak UPS battery with a RGB Pigtail (the R,G & B leads a not connected) that I take to the string, for a quick 1 color at a time test

[~DOC~]

30 minutes ago, TheDucks said:

Yew, the 18W is the input (I also have a few of those SAME from my Network switches, routers) Netgear is Communications equipment. They have a 5Y warrenty, but mainly COM suppliers build for high MTBF because their gear runs 24/7.

Still, that doesn't mean you should abuse them. Great for a short test ( I also have a bunch of 12 3-5A bricks from old LCD panels and stuff)  I also have a old, weak UPS battery with a RGB Pigtail (the R,G & B leads a not connected) that I take to the string, for a quick 1 color at a time test

So your telling me it’s putting out more than it should.

[TheDucks]

10 hours ago, ~DOC~ said:

So your telling me it’s putting out more than it should.

No! (Semantics here) You are DRAWING (overloading) more than you should.   Ohms law.  12V applied to R = I  You control the R

The transformer (rectified) makes 12V.   These are not constant current devices like used for NiCd chargers, that regulated current, by varying the voltage.

First it will overheat, then it may shutdown. Design dictates if it is permanent. (some embed a fuse link to pass UL. Others put a thermal switch)

 

Edited December 21, 2018 by TheDucks