Why all the ports on a controller…

[BrianZ]

I use this: [# pixels] * [type of pixel amp @ 100% white] * [drive level as decimal]

So for your 750 pixels if you are using 5 Volt WS2811 pixels: At 100% White: 750 * .055 * 1.00 = 41.25 Amp (approximately); and at 30%: 750 * .055 * 0.3 = 12.38 Amp (also approximately). Approximately because pixel to pixel their amperage varies a bit and voltage drop down a string causes amperage change as well. The formula as it is will get one in the 'ballpark'.

Something about supplies though that is sometimes overlooked. Wattage rating isn't necessarily a good value to design from. For example: Meanwell's LRS-350-5 supply while called and considered a 350 Watt supply can only deliver 60 Amp on its (DC) output before going into an overload condition. That 60 Amp and 5 Volt calculates to only 300 Watt deliverable. The supply's datasheet shows what's what.

This is great, thanks. And for 12v, I’ll use .112 or .12?

 

[Skymaster]

This is great, thanks. And for 12v, I’ll use .112 or .12?

Neither. The current doesn't change with the voltage. Use 0.055. That's the reason for using current rather than wattage in the calculations.

Unless it's a resistor 12V pixel at which point the current could be anything depending on the design of the pixel.... But you would need to get detail on the design for that.

 

[BrianZ]

Neither. The current doesn't change with the voltage. Use 0.055. That's the reason for using current rather than wattage in the calculations.

Unless it's a resistor 12V pixel at which point the current could be anything depending on the design of the pixel.... But you would need to get detail on the design for that.

I tested 450 pixels on port 1 at 50% brightness with no PI and it did very well. But how is this when port 1 has a 5 amp fuse?

 

[TerryK]

I tested 450 pixels on port 1 at 50% brightness with no PI and it did very well. But how is this when port 1 has a 5 amp fuse?

What color or colors? The formula I previously mentioned is only at 100% White. For only a single color the amperage drops to approximately 33% of 100% White. Two colors 66% of course. Pretty easy to see that with a moving pattern and colors, amperage is all over the map.

I know I probably shouldn't, and I mean no offense, but I just have to ask. Just exactly where did the .112 come from?

 

[Skymaster]

Fuses do not blow immediately. They will hold indefinitely at their rated current, and may take significant time to blow on overload.
This is a table that gives some ballpark numbers



If they are 12V resistor pixels, they may be drawing considerably less than 0.055A per pixel, some have been tested down to 0.01A
There is also wire losses to consider. The wire is very thin and may not be able to carry the full current, dropping the voltage along it, rather than allowing significant enough current to flow.

 

[BrianZ]

What color or colors? The formula I previously mentioned is only at 100% White. For only a single color the amperage drops to approximately 33% of 100% White. Two colors 66% of course. Pretty easy to see that with a moving pattern and colors, amperage is all over the map.

I know I probably shouldn't, and I mean no offense, but I just have to ask. Just exactly where did the .112 come from?

I ran steady white at 50% with 450 12v pixels coming out of one port and I had to PI. Then I color washed them and no PI was needed. I just don’t know how all those pixels held with no issues on one port. Could I run more pixels from that same port with PI? And I mis-read that .112. Yeah….lol.

 

[Skymaster]

If you're PI'ing it throws the fuse right out of the equation.
Because there is a second power path delivering power.

 

[BrianZ]

If you're PI'ing it throws the fuse right out of the equation.
Because there is a second power path delivering power.

Darn, true. But I actually ran 450 at 50% color wash with no injection and they did great. I tested the very end and it dropped to about 10v. But the colors were fine.

 

[TerryK]

Colors again. If the wash is RGB only then the amperage would be 1/3 of the 100% White. And then further reduced by the 50% drive level. If the wash included the 'mixed' colors; cyan, magenta, and yellow; then it would be higher than the 1/3 but still less than 2/3.

Also keep in mind what @Skymaster said, fuses do not open immediately. So the string could exceed the fuse rating as the wash required a higher amperage and the fuse could have a bit of a rest if/when the colors in the string dropped the amperage.

 

[BrianZ]

Colors again. If the wash is RGB only then the amperage would be 1/3 of the 100% White. And then further reduced by the 50% drive level. If the wash included the 'mixed' colors; cyan, magenta, and yellow; then it would be higher than the 1/3 but still less than 2/3.

Also keep in mind what @Skymaster said, fuses do not open immediately. So the string could exceed the fuse rating as the wash required a higher amperage and the fuse could have a bit of a rest if/when the colors in the string dropped the amperage.

Understood. So, I shouldn’t run that many pixels off of one port then, correct?

 

[KStatefan]

A note regarding the Falcon F4v3, while the controller does only have the 4 physical ports it will with expansion support 2 Smart Receivers taking it to 12 ports. And different from its F16/F48 brothers there is no port sharing. So a F4v3 can drive slightly more than 12,000 pixels, at the slower frame rate of course.

If you daisy chain those smart receivers you can get it up to 28 ports maybe 36 if you converted port 1-4 to smart and then hooked up receivers to the serial port.

 

[BrianZ]

If you daisy chain those smart receivers you can get it up to 28 ports maybe 36 if you converted port 1-4 to smart and then hooked up receivers to the serial port.

Yeah, I’m definitely doing this!! Because I’ll have other props and my main F4 controller will almost be used up by the 750 icicle lights. My question is, can I run all lights from one port with PI at 50% brightness? The reason why I ask is, the controller will be at one end of the roof, in the garage and I want to chain them together across to the other side of the roof line. If I use another port, I’ll have to run an extension cable mid-way, which will be about 20-30ft after the first run.

 

[KStatefan]

Set the brightnees you want in xLights then let xLights make all your controller settings.

 

[Indigogyre]

Yeah, I’m definitely doing this!! Because I’ll have other props and my main F4 controller will almost be used up by the 750 icicle lights. My question is, can I run all lights from one port with PI at 50% brightness? The reason why I ask is, the controller will be at one end of the roof, in the garage and I want to chain them together across to the other side of the roof line. If I use another port, I’ll have to run an extension cable mid-way, which will be about 20-30ft after the first run.

What's the difference between running a power injection cable down the length vs running a second port cable down the length? In either case you have to run a cable down the length anyway.

 

[BrianZ]

What's the difference between running a power injection cable down the length vs running a second port cable down the length? In either case you have to run a cable down the length anyway.

Agreed. But the voltage drops a lot by starting from port 2 with a 30ft extension or is this the same if I chain them together anyway? I’m trying to minimize the cabling. But what I may do, is run all the lights from two ports and run one PI cable with 2 PI points. Sounds good?