Parallel Wiring Samsung Strips. And Voltage Hogging

[Prawn Connery]

150W LG driver 3.2 amps split over the strips in a 2S 4P configuration.

so for option two I don't really understand how you mean to go from + to - the red line at the bottom is already connecting the two strips in series is it not? Are you saying using the two inside connectors + and - is different to using the ones to the outside of the board?

No, the bottom strips are NOT connected in series – you have bypassed both bottom strips by connecting the outer tracks so that neither strip will light up because neither strip is getting any current.

I think you need to have another look at those strips to see which terminals are which. The two inside connectors at the bottom are reverse polarity to the two outside conectors. From left to right they are: – + – +

My blue-line diagram shows the current entering the lower-right strip at the top + terminal, exiting through the bottom – terminal, entering the lower-left strip via the bottom + terminal and then exiting via the top – terminal in a series connection.

In your diagram the current follows the green line and does not go through any of the LEDs.


I dont know why you drew it like that because you have the correct terminals connected in the pair of strips above it. Each pair of strips should be identically wired. The only difference is the top pair are fed by the driver, and the bottom pair are fed by the top pair in parallel.

Trust the guy who's done this before. In fact, trust the guy who designs these things

The strip frames I posted were drilled by hand. I used washers under the screw heads to hold the strips down. The trick is not to tighten them too much or they will warp the strips. Tighten them just enough so that the strips lie flat on the extrusion. FR4 does not conduct heat that well to begin with, so the best you can hope for is to have all the strips mounted fairly flat and not run them that hard.

So you are planning to run 8x strips off that 150W driver? That would be about right.

 

[Prawn Connery]

Note the green line crosses the LEDs in this image – which means the current passes through the LEDs before jumping to the next strip. This is what you want. Does it make more sense now? You had it right to begin with but I think you got your + – terminals back-to-front when you drew the red lines at the bottom. You want to go NEGATIVE to POSITIVE at the bottom, and not + to – as you have drawn.

 

[MidnightSun72]

No, the bottom strips are NOT connected in series – you have bypassed both bottom strips by connecting the outer tracks so that neither strip will light up because neither strip is getting any current.

I think you need to have another look at those strips to see which terminals are which. The two inside connectors at the bottom are reverse polarity to the two outside conectors. From left to right they are: – + – +

My blue-line diagram shows the current entering the lower-right strip at the top + terminal, exiting through the bottom – terminal, entering the lower-left strip via the bottom + terminal and then exiting via the top – terminal in a series connection.

In your diagram the current follows the green line and does not go through any of the LEDs.
View attachment 4934386

I dont know why you drew it like that because you have the correct terminals connected in the pair of strips above it. Each pair of strips should be identically wired. The only difference is the top pair are fed by the driver, and the bottom pair are fed by the top pair in parallel.

Trust the guy who's done this before. In fact, trust the guy who designs these things

The strip frames I posted were drilled by hand. I used washers under the screw heads to hold the strips down. The trick is not to tighten them too much or they will warp the strips. Tighten them just enough so that the strips lie flat on the extrusion. FR4 does not conduct heat that well to begin with, so the best you can hope for is to have all the strips mounted fairly flat and not run them that hard.

So you are planning to run 8x strips off that 150W driver? That would be about right.

I appreciate the response. I am not asking out of lack of trust at all. I like to gain a first principals understanding of why something is the way it is. Ok so I wasn't understanding the Samsung PCB circuit correctly at all. But ya I was planning on 8 strips per driver. That way keeps all the strips to 1 heat sink which I like from a modular perspective.

 

[MidnightSun72]

Note the green line crosses the LEDs in this image – which means the current passes through the LEDs before jumping to the next strip. This is what you want. Does it make more sense now? You had it right to begin with but I think you got your + – terminals back-to-front when you drew the red lines at the bottom. You want to go NEGATIVE to POSITIVE at the bottom, and not + to – as you have drawn.
View attachment 4934398

Yes I get it now. I was cutting the LEDs out of the path basically?
Edit: basically jumpering around them.

 

[Prawn Connery]

Yes I get it now. I was cutting the LEDs out of the path basically?
Edit: basically jumpering around them.

Yes! You've got it!

The reason there are two + terminals on one side of the strip and two – terminals on the other is because those outer tracks are used to connect strips in parallel. The current enters the first + terminal and goes through the LEDs, but the current is also carried to the other + terminal so that it can be passed on to another strip. Once you know how the strips are wired it all starts to make sense. I will admit, it is a bit confusing until you wrap your head around it. I just said "trust me" coz it's a figure of speech . . . and because I've done this a few times before

 

[MidnightSun72]

Yes! You've got it!

The reason there are two + terminals on one side of the strip and two – terminals on the other is because those outer tracks are used to connect strips in parallel. The current enters the first + terminal and goes through the LEDs, but the current is also carried to the other + terminal so that it can be passed on to another strip. Once you know how the strips are wired it all starts to make sense. I will admit, it is a bit confusing until you wrap your head around it. I just said "trust me" coz it's a figure of speech . . . and because I've done this a few times before

Do you find there a measure able voltage difference between the first set of strips and the second set of strips that are paralleled? Or is the PCB ample enough to avoid measurable drop over 2 ft?

 

[Prawn Connery]

There will be some slight voltage drop, and there will be a very small difference in current between the top pair of strips and the bottom pair (due both to the slight voltage drop and slightly more resistance due to the extra wiring), but it won't be that noticeable. You could always have a hole in the middle of the extrusion and feed each pair evenly, but if it were me I wouldn't worry too much about it.

 

[Grow Lights Australia]

I've built a few of these H-Series strip frames in the past and this is how I did it with side-by-side strips. I wired two strips in series for 48V, and the rest in parallel.

Option 2 is almost correct. But what you need to do is at the very bottom, run – to + (instead of + to – as per your wiring diagram). This will provide one pair of series strips (48V) connected in parallel to another pair of series strips (48V).

If you use my example below, take the first pair of strips on the very far right, move it directly below the second pair of strips to the left. You can see now how the white (–) and red (+) wires from the strip on the left line up with the – and + terminals on the strip below, which is being fed by the driver.

Have a look at the image I have drawn at the bottom. Delete the red lines and insert the blue lines.

View attachment 4934271

This will work. The current flows from the driver through the first strip at the + terminal where it is connected in series to the strip next to it with the current flowing back to the driver through the – terminal. However, the bottom of this pair of strips is also feeding current to the pair of strips below which are wired exactly the same as the strips above. The current is being carried through the outer + track and returned by the outer – track.

Does it make sense now?
View attachment 4934289

I remember those! If I remember correctly those H strips produced some nice results. I like how the LEDs are spaced and the strips themselves are usually pretty cheap. Even though they are an older design they are still quite efficient due to the LED spacing. We've still got a bunch of them I've been meaning to turn into cheap lighting frames. @MidnightSun72 please keep us all in the loop with your new project as I'm very interested to see how it turns out. I like what I've seen so far!

 

[Prawn Connery]

Yep, those H-Series strips certainly did grow some nice plants.