I wanted to test, to see when I would need a Null Pixel for my situation. It is commonly said that for distances greater than 5 metres, you will need a null pixel.
My conclusions are that the Ground cable size is very important. At a larger distance, the voltage drop caused the data signal "return" to fail, as the ground was being used mostly by pixel power return. Use a bigger cable for the ground, and suddenly you can increase the distance. At 6 metres using standard wires, the lights fail. If you double the ground cable, then 6 metres works fine. Use thicker cable for positive and ground, and then you can get to 9 metres, without a null pixel.
I used a basic test bed, and intended to vary the cable type and length to see what I would discover.
PixLite 16 (12V) -> pigtail -> Watt's Up meter -> test wire -> pigtail -> pixel string -> digital voltage meter
The pixel string for most of my tests was not a simple standard string. It is 5 x one metre string of 20 pixels, with pigtails on each end, connected together giving 100 pixels over about 6 metres. So my test bed had the signal flowing through 12 pigtails, in total.
They are all Ray Wu black 4 core pigtails [SIZE=78%](presumably 18 AWG)[/SIZE][/size][SIZE=78%].[/SIZE]
The wire is Ray Wu's 4 core RGBB cable (presumably 18 AWG).
I also used some 2 core 12V garden cable - 12 AWG.
First test, using 4 core RGBB - 6 metres - when white (255) the lights were flasing, not steady. Far end voltage was 11.3 V when all off, 6.9V when full white. Peak Amps 3.2A
Second test using 4 core RGBB for signal and positive - 6 m - plus 1 core 12AWG for ground, 8 m. Everything worked as normal. [/size][SIZE=78%]Far end voltage was 11.3 V when all off, 6.9V when full white. Peak amps 5.2A[/SIZE]
Third test, using a single core of the 4 core RGBB cable (for data) 9 metres, plus 2 cores of the 12AWG, 8m. Everything worked as normal. Far end voltage was 11.6V when all off, and 7.2V when full white. Peak amps = 5.4A
Fourth test, same as third but data cable was 6 metres. Far end voltage was the same, Peak Amps the same.
Fifth test using 4 core RGBB, with Black & Blue joined (ground), 6 metres, everything normal, Far end voltage 11.4V for off, and 5.54V for all white. Peak amps = 4.8 A
Last test using a "normal" pixel string ( 100 pixels on 10 metres), 4 core RGBB (not using blue), 6 metres, and as expected, lights flashing on full white.. I watched this one closely. As the white level increased, the pixels got brighter, up to about 188 (far voltage showing 5.7V). As the level continued to increase, more and more pixels started to flash. And as more pixels flashed, the end voltage increased so that at 255, the voltage was 8V, and the pixels were really flashing erratically.
My conclusions are that the Ground cable size is very important. At a larger distance, the voltage drop caused the data signal "return" to fail, as the ground was being used mostly by pixel power return. Use a bigger cable for the ground, and suddenly you can increase the distance. At 6 metres using standard wires, the lights fail. If you double the ground cable, then 6 metres works fine. Use thicker cable for positive and ground, and then you can get to 9 metres, without a null pixel.
I used a basic test bed, and intended to vary the cable type and length to see what I would discover.
PixLite 16 (12V) -> pigtail -> Watt's Up meter -> test wire -> pigtail -> pixel string -> digital voltage meter
The pixel string for most of my tests was not a simple standard string. It is 5 x one metre string of 20 pixels, with pigtails on each end, connected together giving 100 pixels over about 6 metres. So my test bed had the signal flowing through 12 pigtails, in total.
They are all Ray Wu black 4 core pigtails [SIZE=78%](presumably 18 AWG)[/SIZE][/size][SIZE=78%].[/SIZE]
The wire is Ray Wu's 4 core RGBB cable (presumably 18 AWG).
I also used some 2 core 12V garden cable - 12 AWG.
First test, using 4 core RGBB - 6 metres - when white (255) the lights were flasing, not steady. Far end voltage was 11.3 V when all off, 6.9V when full white. Peak Amps 3.2A
Second test using 4 core RGBB for signal and positive - 6 m - plus 1 core 12AWG for ground, 8 m. Everything worked as normal. [/size][SIZE=78%]Far end voltage was 11.3 V when all off, 6.9V when full white. Peak amps 5.2A[/SIZE]
Third test, using a single core of the 4 core RGBB cable (for data) 9 metres, plus 2 cores of the 12AWG, 8m. Everything worked as normal. Far end voltage was 11.6V when all off, and 7.2V when full white. Peak amps = 5.4A
Fourth test, same as third but data cable was 6 metres. Far end voltage was the same, Peak Amps the same.
Fifth test using 4 core RGBB, with Black & Blue joined (ground), 6 metres, everything normal, Far end voltage 11.4V for off, and 5.54V for all white. Peak amps = 4.8 A
Last test using a "normal" pixel string ( 100 pixels on 10 metres), 4 core RGBB (not using blue), 6 metres, and as expected, lights flashing on full white.. I watched this one closely. As the white level increased, the pixels got brighter, up to about 188 (far voltage showing 5.7V). As the level continued to increase, more and more pixels started to flash. And as more pixels flashed, the end voltage increased so that at 255, the voltage was 8V, and the pixels were really flashing erratically.