Power Supply Question

[NTJP]

Trying to understand power supply.  If I have 1600 12 volt nodes that would be .72 watt per node or 1152 watts for all 1600 nodes at full power/white light.  So if I run it at half power it would be 576 watts and at 30% 345.6 watts.  A 350 watt power supply should not have a load of more than 80% or 280 Watts.  So, with that said, if correct.  Would need 2 power supplies to run the 1600 node Mega Tree at no greater than 48%, which would be 553 watts?  Is this correct???

[flyinverted]

That is 100% math theory correct on paper.

Once you get your lights, you'll discover that the output is non-linear. Plan for 100% but reality will usually be less consumption than that.

Try it, you'll see what I mean.

-Steve

[algerdes]

One thing that all (including me) seem to forget is that their is a power draw at each of the pixels, even when they are not lit.

I suggest you put a meter on a string, measure how much that string takes un-lit, then measure how much the string uses when fully lit.  This would give you a better idea as to how much you are using, how much you can put on a power supply, and how much you would have to "dial down" the intensity.

[babybear]

The whole thing I have to laugh  paper, what the paper says . I have a tree with 3600 lights   the Lights are listed at .3 watts each. so that would be 1080 watts.  Im running at 65% and at full white my meter has never gone over 290 watts or 26 amps. Any one else seeing what I'm seeing? Do I have a bad meter?

[algerdes]

I have had the same experience.
Paperwork says one thing, testing says something else.

[NTJP]

I am trying to figure out what to order since I am going all pixel on the house.  So, was afraid someone would say test the strings.  Which I have not bought yet.  I think I will work on the theory it will not take no more power supplies than half of what is needed at full power.  Plan to run at 25% to 30%.  Mega tree looked great this year at 25% but I am doubling the number of strings on it for next year.  I have mapped out the house with number of pixels.  This gives me number of watts/amps per section or controller.  So, from that I will know how many power supplies needed and where.  In theory I should have more power supplies than needed, which gives me backup/expansion power supplies. 
Thank you for the replies.  It was a great help to know I am on the right track. 

[jnealand]

While you are ordering power supplies I would recommend that you order at least one spare.  Having a power supply go south in the middle of a show season is not a pleasant experience and you will want to recover as quickly as possible.  It's not a high cost for a little backup.

[Texdentist]

I agree.  I had a power supply die this year, and having a spare meant I had 1/2 of a mega tree down for thirty minutes.  I won’t be without a couple of spares from now on.


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