Power Injection - Back Feeding Issue - Singular PSU

xdandev91x

xdandev91x

New elf
Joined
Dec 5, 2020
Messages
23
Hi,

I must be doing something wrong here. When I am power injecting via a Tee, it appears to 'taking voltage' from the following props to the point where they stop working. Then removing the power injection, causes things to work again (to the point where lack of power injection is the issue). I'd wager I'm back feeding the power supply.

For context, I've got a power supply LRS-600-12 connected to the F16v4 controller. The same power supply has 2 pin xconnect pigtails connected to its other outputs which I'm using for power injection.

The strings are connected to the controller output for display. After 150 pixels or so, I've got a power injection tee (3-2-3), with the 2 pin going straight to the pigtails connected directly to the power supply. This causes the backfeeding.

Now short of getting the f8 power distro boards which is next years project, I thought back feeding wasn't an issue when using the same power supply?

In other instances where I'm using power injection across multiple power supplies, I've pulled out the voltage-in pin from the power injection tee so the previous power supply won't feed the other. This seems to work.

What am I doing wrong for the singular power supply string? I tried using a power injection tee with the voltage-in pin removed as well, and to be frank, I almost blew a fuse during testing.
 
Can you do a quick paint / sketch drawing what you're doing? Just lines with V+, V- and data is sufficient and any shape for prop - does not need to be precise, just an accurate diagram of your wiring.
 
xdandev91x said:
Hi,

I must be doing something wrong here. When I am power injecting via a Tee, it appears to 'taking voltage' from the following props to the point where they stop working. Then removing the power injection, causes things to work again (to the point where lack of power injection is the issue). I'd wager I'm back feeding the power supply.

For context, I've got a power supply LRS-600-12 connected to the F16v4 controller. The same power supply has 2 pin xconnect pigtails connected to its other outputs which I'm using for power injection.

The strings are connected to the controller output for display. After 150 pixels or so, I've got a power injection tee (3-2-3), with the 2 pin going straight to the pigtails connected directly to the power supply. This causes the backfeeding.

Now short of getting the f8 power distro boards which is next years project, I thought back feeding wasn't an issue when using the same power supply?

In other instances where I'm using power injection across multiple power supplies, I've pulled out the voltage-in pin from the power injection tee so the previous power supply won't feed the other. This seems to work.

What am I doing wrong for the singular power supply string? I tried using a power injection tee with the voltage-in pin removed as well, and to be frank, I almost blew a fuse during testing.
Click to expand...
1000099937.jpg
 
Pavle said:
Can you do a quick paint / sketch drawing what you're doing? Just lines with V+, V- and data is sufficient and any shape for prop - does not need to be precise, just an accurate diagram of your wiring.
Click to expand...
Almost beat you to it with my diagram. Replied to my own post with the "technical diagram".
 
I can't see any issue with your wiring. Confirming the 150 pixels is the end of the line?
Only thing I could suggest is testing by running an additional 2 wire cable to the very end so you would have power going in at the start, middle and end.
 
Pavle said:
I can't see any issue with your wiring. Confirming the 150 pixels is the end of the line?
Only thing I could suggest is testing by running an additional 2 wire cable to the very end so you would have power going in at the start, middle and end.
Click to expand...
This is what scares me haha. I've gone through what I thought was every possible YouTube video on power injection and was so confident it was correct.

Yeah I'll add power at the end once I've figured out this first. Conscious I don't want to add more variables to the mix.

There is nothing connected to the end of that pixel line.
 
My understanding of power is you can't really have too much. The pixels will only draw what they need.
So long as you have enough power, and you add the power at points accounting for voltage drop (ie: so you minimise any), you are good to go.

Back feeding isn't really a thing - I mean, sure, power does travel in both directions, but if the source is the same, then it's just a circuit.

Is there only this power supply going into your controller?
Are you powering both sides of the controller? Assuming if above is yes, there is 2 connections being used to go to both sides of controller?
 
Have you got a multimeter? Confirm you are getting 12v (in the correct polarity) direct off the power supply and then at each end of the T. It almost reads like the 3-2-3 has an issue with the data line, so check there is not connectivity between the data and the +ve or -ve on the 3-2-3 as well. Note that you can't check data continuity across the pixels, you can only check on the 3-2-3 directly.
 
Pavle said:
My understanding of power is you can't really have too much. The pixels will only draw what they need.
So long as you have enough power, and you add the power at points accounting for voltage drop (ie: so you minimise any), you are good to go.

Back feeding isn't really a thing - I mean, sure, power does travel in both directions, but if the source is the same, then it's just a circuit.

Is there only this power supply going into your controller?
Are you powering both sides of the controller? Assuming if above is yes, there is 2 connections being used to go to both sides of controller?
Click to expand...
Only one power supply going to both sides of the controller.
 
merryoncherry said:
If I had to guess, there is a polarity accident of some sort... reversed, or both ground or both positive, as people do this all the time and it works consistently.
Click to expand...
You've got me paranoid haha. When I get home tonight from work, I'm going to check every single connection etc. If this is truly the case, my deepest apologies for wasting everyone's time haha.
 
xdandev91x said:
You've got me paranoid haha. When I get home tonight from work, I'm going to check every single connection etc. If this is truly the case, my deepest apologies for wasting everyone's time haha.
Click to expand...
Don't worry too much, most of us have all blown fuses, power supplies and the like during our time. It is how we learn and hopefully don't cause fires. This hobby throws up all sorts of weird stuff. One lot of seeds I got from China last year had the negative wire with dots, even though the vendor said the dots were on the positive. I've stuffed up enough times with cabling that I now always check 3 times visually and usually do a continuity test with the multimeter.
 
JacksonHo said:
Don't worry too much, most of us have all blown fuses, power supplies and the like during our time. It is how we learn and hopefully don't cause fires. This hobby throws up all sorts of weird stuff. One lot of seeds I got from China last year had the negative wire with dots, even though the vendor said the dots were on the positive. I've stuffed up enough times with cabling that I now always check 3 times visually and usually do a continuity test with the multimeter.
Click to expand...
I've blown fuses, power supplies.. tripped the electric more times than I'd like to count.. it happens the the hobby and we all learn :)
 
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