Noob Questions

[Dave_Szoka]

I'm not sure, but my guess would be that the PI's don't push data as far as say a Falcon

look at these
http://www.hansonelectronics.com.au/product/null-buffer-rtg1/

they are a Null Buffer... means you don't need to add a Null Pixel to your config

 

[JohnsRdChristmas]

Looking to run passed my gutter line setup, as really not sure if im on the right track,
And as iv just bought a house, i would rather not burn it down

I am running some ws2811 60 led per meter strip, which come in 5mtr lengths,
I have purchased a ton of Ray Wu's pigtails and extension leads

I was going to run 4 lengths of strip, 5mtr, 3mtr, 5mtr, 3 mtrs (so 16mtrs)
And power it off a power supply i have got from 3d printers, (240watt, 20 amps ) and i know that these are cheap Chinese PSUs so shouldn't really be run at any more then 75% so 180watt max, ( I have a few of these so can run multiple if need be)


Questions:

1. - Watts
The strip according to the packaging states maximum power is 36w,
( The packet is for 5mtr roll, so presuming that it is for the roll)
but different calculators i have looked around have it at around 50 watts,

Do i believe the packet?? if so that is 7.2watts per MTR
7.2watts x 16mtrs = 115.2watts
(If thats the case, then im good)


2. - Amps (& Fuses)
I have not thought about it until now, but should fuse each of the power lines for safety, in-case water gets in
and creates a short,
In which case i have ordered some 8 way fuse boards from da-share.com,

I cannot find amp specs on for the strip, but have tested myself???
I have put a multi meter (in amp mode) in the power line before a strip (running power through multi meter)
On full white it draws between 3 - 3.5 amps, (no power connected at end and the colour does dip a little on white at the end - normally would have power injection at end but for the purpose of the test i didnt)
On colours (sample show sequence) it runs around 1.5 - 2.5 amps,

My conclusion
Watts - Now giving a bit of room for overhead, im guessing i can in theory run all 4 strips together off the 1 power supply and the power supply should be fine

Amps (Fuses and Wiring) If i fuse each power line with a 7.5amp fuse then i should be safe, however not sure how best to connect the strands


Can i connect all 4 together like the picture, or do i need to separate it a little, are the fuses effective if there are 5 leeds connected together essentially?
Maybe i should be connected only 2 strips together and have power at start, between and end,

Thoughts?
I really appreciate all the help and advice, I think i am on the right track but safety is important so best to check,

Many thanks

Ben

 

[Dez]

Yes a null pixel is needed

 

[Nuzzy]

I usually work to around 7 watts per metre for a 30 led/metre strip so I would assume a 60 led/metre would be close to double that, maybe around 12 watts/metre.

 

[JohnsRdChristmas]

Hey Dez / Nuzzy

One thing I forgot to mention previously was that all the testing was at 100% brightness (which ofcorse I design for) but when I actually had it up for Christmas 30% was fine, as such all my specs were well under and everything (for roofline) ran flawlessly,

And I had a second psu with a group of elements in front yard and the fuses did their job,
I had water get into an element and blew a fuse, so glad I put them in,

Was a great first year and learnt a lot and already looking to start designing and costing out next year's setup, got the green light from the wife!!

Many thanks for the replies, hope you both had a great tg season,