Maximum reasonable 12v pixel lead length

[jtomason]

Yes, I know, last minute prop building...  Bad Joe... Bad Joe!

You'd think this info would be easier to find, but apparently my Google-fu is weak today.   I am building a 2811 pixel prop for the second floor, and there's no easy way to get 120vac up there without something I don't have time for (like adding an outlet or something) and I don't really want to run extension cords up there.    So I am thinking that keeping the controller and power supply on the ground and running the data and power cable up to the props is a better idea, but I don't know how long of a run will incur too much data signal loss, voltage drop, etc.    It should be maybe 50' maximum.  

Any words of wisdom before I start cutting wire?

Thanks!

 

[TheDucks]

If in doubt bump the wire gauge 😁 You need 11 (10.8)V AT THE FAR END (standard +/- 10%) to avoid poor color

A 50 cnt bullet string take ~3A (All Wh) 18Ga for 20' is no prob .  (We are talkin Voltage drop. Power inject at the far end and you now  worry about Data. I believe LOR cotrollers will do 25' to first node. Got longer: Insert a null pixel in the middle of the home run. (note: Pixies count that as a Node)

[k6ccc]

Possible, yes.  Just varies how much effort will be required.  For data, there is not total limit as you can just keep adding null pixels.  How far you can go and how often you need to add null pixels will vary A LOT depending on what specific devices are used.  You largely need to test what you will be using.

For power, there are ways to get substantially longer power, but it involves higher voltage and regulators.

 

[jtomason]

1 hour ago, TheDucks said:

If in doubt bump the wire gauge 😁 You need 11 (10.8)V AT THE FAR END (standard +/- 10%) to avoid poor color

A 50 cnt bullet string take ~3A (All Wh) 18Ga for 20' is no prob .  (We are talkin Voltage drop. Power inject at the far end and you now  worry about Data. I believe LOR cotrollers will do 25' to first node. Got longer: Insert a null pixel in the middle of the home run. (note: Pixies count that as a Node)

 

This is an (old, inherited) PixLite 16 controller.    The power supply I am using appears to have variable voltage, so presumably I can up it in .5v increments?  What's the maximum voltage a ws2811 can handle before you let the smoke out?

 

 

1 hour ago, k6ccc said:

Possible, yes.  Just varies how much effort will be required.  For data, there is not total limit as you can just keep adding null pixels.  How far you can go and how often you need to add null pixels will vary A LOT depending on what specific devices are used.  You largely need to test what you will be using.

For power, there are ways to get substantially longer power, but it involves higher voltage and regulators.

 

The pixel string lengths won't be long - 200 pixels (window outline) and 100 pixels (2 snowflakes), each on their own line. 

 

Joe

 

[TheDucks]

I set my supplies to * 1/2 the tolerance  (assumes the supplies are stable over  the load range presented. (all lights Off-All n)

12.6V is my All Off set point Safe by a 5% margin

[jtomason]

So partial success.  

The string of the first 100 pixels lit up on the end of the cable - but I didn't scrutinize white.   Get it installed on the roof and white is shifting in color temp as the string goes on.  R, G, & B look OK I think (it's raining).

Cranked the power supply up to nearly 14v at the controller (from 12.2v) and that did not seem to make much - if any - difference.  

I do have extra lead on this run that I can trim, but since raising the voltage didn't seem to help, I'm not sure that lopping off the 10' or so extra I had will make much of a difference either. 

Any words of wisdom?

 

[k6ccc]

27 minutes ago, jtomason said:

The string of the first 100 pixels lit up on the end of the cable - but I didn't scrutinize white.   Get it installed on the roof and white is shifting in color temp as the string goes on. 

Bet the end is shading towards pink.  That is typical of low voltage at the end of the string.  Injecting power at the end of the string is the easiest solution.

 

[dibblejr]

4 hours ago, jtomason said:

So partial success.  

The string of the first 100 pixels lit up on the end of the cable - but I didn't scrutinize white.   Get it installed on the roof and white is shifting in color temp as the string goes on.  R, G, & B look OK I think (it's raining).

Cranked the power supply up to nearly 14v at the controller (from 12.2v) and that did not seem to make much - if any - difference.  

I do have extra lead on this run that I can trim, but since raising the voltage didn't seem to help, I'm not sure that lopping off the 10' or so extra I had will make much of a difference either. 

Any words of wisdom?

 

Raising the voltage may cause the pixels to start burning out at the beginning of the string. Just something else to consider.

JR

[jtomason]

4 hours ago, k6ccc said:

Bet the end is shading towards pink.  That is typical of low voltage at the end of the string.  Injecting power at the end of the string is the easiest solution.

 

Yep.  Looks like I will have to run injection power from the ground.   (sigh)

 

29 minutes ago, dibblejr said:

Raising the voltage may cause the pixels to start burning out at the beginning of the string. Just something else to consider.

JR

Yeah, that's why I only went up a volt or so to see if it would make a difference, then lowered it back down when it didn't.