How big a power supply?

[algerdes]

This is both a need, and an academic exercise.
We have a matrix that is 24 wide and 48 tall. (Vertical oriented.)
It will be pushed by a Kulp K8 as a stand-a-lone, running Christmas images.

When figuring the size of the power supply needed, from 4 different blinky-heads, we have 4 different answers (hence the "academic exercise".)

We decided to ask others what they would use.

With this matrix (again - 24 x 48 = 1152 pixels), what size power supply would you use?

[kenoman742]

Assuming these are 12v pixels, 1152 pixels would require a maximum of about 70 amps of power. Of course that requirement could be reduced by not running the pixels at 100% brightness, and most of us don't. You would probably need 2-3 30 amp power supplies or 1 1200 watt server power supply.

[k6ccc]

Depends on your pixels too.  For this calculation I use 60mA per pixel so I agree with kenoman at just under 70A (at 100%)
And don't plan on running power supplies at 100% - higher probability of a failure.

[algerdes]

"But failure is a learning experience!"  

Running the pixels at 30% (max) and using a 350 watt 12 vdc power supply is in the plan.  I will take the chance of one of those "moments" where someone does something to cause a 100% moment (such as turning on a test pattern of all white.)

Thanks for the input folks. 

Take care.

[jnealand]

mmmm  I have a matrix of 1000 12v pixels 20hx50w and I have been running it with one meanwell PS for 2 years,  This will be year 3 and it still worked great for Halloween.  It runs from one port of a PICap with two PI spots at 30%.

[algerdes]

mmmm  I have a matrix of 1000 12v pixels 20hx50w and I have been running it with one meanwell PS for 2 years,  This will be year 3 and it still worked great for Halloween.  It runs from one port of a PICap with two PI spots at 30%.

But you just have the magic touch Jim.

[k6ccc]

If all else fails, measure the actual current.  Today I was replacing the lights in front of my roses - part of my year round landscape lighting and also heavily used for Christmas.  Complete change of what pixels, how they were powered and how they were driven.  I was not concerned about load on the power supply, but I was concerned about load on the Smart Differential Receiver outputs and the power injection at the far end.  So my test was to turn off test mode, pull the Receiver fuse for the longer string, put an amp meter in place of the fuse, and put the test mode into full white.  With the PI at the end of the string taking about 40% of the current, I maxed out the Receiver output port at just under 3 amps.  Me happy!
Better yes, my roses lights are fully operational - something that has not been the case for quite a while...

[algerdes]

If all else fails, measure the actual current.  Today I was replacing the lights in front of my roses - part of my year round landscape lighting and also heavily used for Christmas.  Complete change of what pixels, how they were powered and how they were driven.  I was not concerned about load on the power supply, but I was concerned about load on the Smart Differential Receiver outputs and the power injection at the far end.  So my test was to turn off test mode, pull the Receiver fuse for the longer string, put an amp meter in place of the fuse, and put the test mode into full white.  With the PI at the end of the string taking about 40% of the current, I maxed out the Receiver output port at just under 3 amps.  Me happy!
Better yes, my roses lights are fully operational - something that has not been the case for quite a while...

Good to hear you are back up and working.  My only suggestion is to be very careful when pruning/triming those roses.  No sparks, please.

[k6ccc]

Good to hear you are back up and working.  My only suggestion is to be very careful when pruning/triming those roses.  No sparks, please.

Nope, no sparks.  I prune the roses with hand pruning sheers.  I will do that in January after the show gets taken down.  The permanent completion of the rose lights project will happen after the roses are pruned.  A whole lot easier to work around the roses after they are pruned.  That's what happened this year.  I was going to do this after pruning the roses and did not get to it.  By the time I had time, the roses were three to four feet tall...