Author Topic: megatree power requirement?  (Read 493 times)

Offline rickswa

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megatree power requirement?
« on: February 22, 2018, 12:43:33 PM »
Hello All,

Im planning on doing a megatree this year using 12v ws2811 nodes from Ray but want to make sure my math is correct.  I plan to use 24 strings of 124 pixel nodes for a 360 degree tree that's 10'6" tall and 5' wide at the base with 1" node spacing using boscoyo strips. 

The calculations that I came up with (using 75% brightness just to be conservative...probably be more like 55 or so) was 5.58A/strand of 124 pixels.   That puts the entire tree of 2976 pixels requiring 134A.  I plan to use mean well 350W 12V power supplies and if I limit them each to 85% of max, this should give me 25.5A DC output per supply.  Is this correct that it will take 5 (actually 5.25) power supplies to power this tree of 24 strings of 124 nodes? 

Also, does anyone know the AC draw of a 350W power supply?  I'm just concerned that this will draw more power from the house than I thought.  Thanks for any help.

Offline jnealand

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Re: megatree power requirement?
« Reply #1 on: February 22, 2018, 01:57:25 PM »
75% brightness on 1" spacing will be so bright you will not be able to take a photo or video.  I use 30% brightness and use 3" spacing.  I would not recommend more than 2" spacing.  That will also reduce your power needs.
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Online pixelpuppy

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Re: megatree power requirement?
« Reply #2 on: February 22, 2018, 02:13:46 PM »
I know you asked about power, but I would seriously re-consider your pixel layout/spacing.

Given your base diameter of 5' and 24 strands in a 360-degree arrangement, the spacing of those strands at the bottom of you tree is going to be close to 8" apart.  Then you said 1" pixel spacing on the strands to the will be very tight spacing vertically and very sparse spacing horizontally.

My suggestion is to go with 2" vertical spacing and make 48 strands.  Same total number of pixels but then you will have pixels spacing pretty close to equal 2" horizontal and 2" vertical in the middle of the tree.  Being a tree, of course, its tighter at the top and wider at the bottom but spacing it close to equal in the middle give the best visual results - especially if you do any pictures, graphics, or faces on the tree.
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Offline Emuney18

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Re: megatree power requirement?
« Reply #3 on: February 23, 2018, 11:39:45 AM »
I would also be worried about 1" spacing.  I had a matrix with 1" spacing this year and had to turn the brightness down to 10% and anything over 20% was too bright to make out even text.  I would do what pixelpuppy said.  My tree is 12.5' with 2" spacing with horizontal spacing at the bottom around 5.5" spacing.  This was really nice.

Offline rickswa

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Re: megatree power requirement?
« Reply #4 on: February 23, 2018, 01:31:28 PM »
Thanks for all the great replies.  It sounds like your tree is pretty much the same as I plan on.  I currently have the strawberry style LED's and switching over to pixels this year.  I'll definitely go with the 2" spacing and 48 strands.  My only concern now is that I have a 7" top piece for the strips to mount to but wonder if I'll have difficulty getting 48 strips to attach to the 7" top. 

Emuney, can I ask what your power consumption is on your tree?  Do you think my calculations earlier are good to use but just scale down for the brightness?

Also, any rough guidelines on how much AC power the 350W DC supply takes?

Thanks again for the great advice.  I really appreciate finding now rather than when I do it wrong and wish I had done it differently.

Offline jnealand

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Re: megatree power requirement?
« Reply #5 on: February 23, 2018, 03:00:26 PM »
48 strands is a lot.  I would suggest you start by building 24 strands and trying it out.  You may find that it does exactly what you need.  You can always add more strands.  I use 24 strands in a 270 deg config.  48 strands would be double that and even in a 360 deg config I think it may be more than you need.  Start early and start small.  Put it up in your backyard in July and see.  Just my 2 cents.

Offline Emuney18

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Re: megatree power requirement?
« Reply #6 on: February 23, 2018, 06:37:40 PM »
AC power is the wattage divided by the voltage (110-120 in the US). So about 3 amps of household current per power supply.   I didn't measure Rays nodes this year but I did DIYLEDEXPRESS last year and they were 5.5 amps per 100 nodes.  I have seen others say 4.5 amps per 100.  Either way I calculate based on 5.5 to be conservative.  My tree was 24 string of 75=1800 nodes. That's 99 amps.  I ran my tree at 30% so that's only 30 amps roughly.


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Offline aknflyer

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Re: megatree power requirement?
« Reply #7 on: February 24, 2018, 12:29:58 AM »
My only concern now is that I have a 7" top piece for the strips to mount to but wonder if I'll have difficulty getting 48 strips to attach to the 7" top. 

I ran a 24 string 180 tree x 50 pixels. Top was 14" diameter, bottom 6', 2" pixel spacing, 1" spacing between the j-hooks. This is the bare minimum you could go. I had to bend a couple of boysco aluminum strip anchors to get them to hook on the top. Looking back, I would go maybe 2" larger to avoid the interference.

Offline rickswa

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Re: megatree power requirement?
« Reply #8 on: March 12, 2018, 12:28:23 PM »
Thanks for all the great replies.  So now I'm thinking 24 strands to start but still 360 tree.  flyer, when you say 2" larger, do you mean 2" larger than my 7" top mount?  I really appreciate all the input but I was now thinking of the 24 strand 2" vertical spacing tree with the 7" topper and 5' base.  The only problem with changing sizes (especially the base) is that I have jumped the gun apparently too early and purchased the parts already.  BUT if the top will be too small, I'll just have to suck it up and get a larger one.  The base, that will have to stay 5' because of yard constraints.  Thanks again for all the great help.

Offline aknflyer

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Re: megatree power requirement?
« Reply #9 on: March 13, 2018, 09:56:21 PM »
flyer, when you say 2" larger, do you mean 2" larger than my 7" top mount? 
Well yours is 360 and mine was 180. With 1 inch spacing between the j-hooks, the strips overlap each other a bit at the top. A couple j hooks were a hair closer and that was why I had to bend the aluminum anchor in the boysco strip to squeeze it past the adjacent j-hook. In hindsight, if I had to replace a middle string I would have had to remove other strings at the top to get that one off, or unbolt the j-hook. That is why I said 2 more inches in diameter would eliminate the overlap for me.

Offline jnealand

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Re: megatree power requirement?
« Reply #10 on: March 14, 2018, 09:31:05 AM »
I've never had to bend a misr clip, but they are tight.  I have to give them a slight twist to get on and even if they are just a bit overlapped at the top there does not seem to be any impact on the lights.  Getting one off in the middle can be tricky, but it can be done.  I've done it.

Offline taybrynn

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Re: megatree power requirement?
« Reply #11 on: March 14, 2018, 05:46:01 PM »
You want fairly similar horizontal and vertical spacing if possible ... so think about how sparse 24 verticals on a 360 will be (very far apart) ... and then compare that to 1" vertical space (very dense) ... its not a good match, IMHO.


I've got some 24 vertical trees on a 180 (front facing only) and they are 46 vertical nodes each on 10' 1/2 megatree  ... can recall the exact spacing but its closer to 3" I think and with the width between verticals is similar, maybe a bit more.


You also run into a horrific space issue up top ... and tbh, you can't tell whats going on up there ... so even with 3" spacing ... its marginal up there ... and you don't want a huge flat top either.  The workaround is a larger top, but your sacrificing a lot in looks for very little return (up there), imho

 

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