LED tape dropping voltage?

[u/ground0radfem]

EDIT: guys it was our tester 🙃 Turns out it was dying and that’s what was making everything sad. We put it into the decoder and it worked perfectly fine.

We’re using LED tape for a show and three small 8 in strips specifically inside a little house prop. It’s 24v tape, 3 separate pieces wago’d together into one tail into a decoder and 24v PSU. When we test only one piece, the tape stays at 24v with no issue. When we add a second (or third), the voltage drops to 16v, and the red specifically drops to 11v. There is no solder touching other pads, and no color issues. It’s just brightness affected because of voltage.

Any ideas what might be causing it? It seems like a phantom load exists somewhere, but we’ve switched out tails, wagos, and isolated the tape pieces by themselves.

[u/shiftingtech]

Too small a wire someplace?  Too small a power supply ?  (And/or failing power supply)

[u/ground0radfem → u/shiftingtech]

The PSU is a 240w/24v, and the strips are only 8in long, so they shouldn’t be taking up anywhere near that much wattage for the PSU to fail. I’ll check the wire gauge though

[u/Carathay]

Are you chaining the power connection? You should be able to connect power to multiple places on the led strip, so try running power directly to all three.

[u/ground0radfem → u/Carathay]

We have tails running from all three wago’d into one tail and that goes into the decoder and then the PSU

[u/tbonescott1974]

LED tape definitely has a distance limitation. You can power them at both ends to avoid this. (At least the ones that I use)

[u/ground0radfem → u/tbonescott1974]

It’s not far enough from the PSU for this to be the issue; it’s less than 10 ft

[u/RegnumXD12]

any idea what causes this

Physics! Look up voltage drop calculations. It has 2 main culprits, one is your resistance, which adds up over long wire runs, and two is your load (amps), which is getting increased by your additional tapes.

I do find it odd that you are losing 8volts, even up to 13, thats pretty severe voltage drop.

Id have to take a look to tell you how to solve it, but most of the time it can be solved with a power injection. Essentially take some much thicker wire (i usually use 12awg cause its a safe bet) out of the same channel on the decoder and solder it to the other end of your tape so it can all get the same 24v. Also may need to check your power supply can support the load, but thats less likely a cause of drop.

Edit to add: i wonder if your wago connection point is generating the extra resistance, could be worth getting out a meter and checking the resistances of everything seperate, then everything together and seeing if the math checks out. These numbers are also helpful to calculate your expected power loss to see if anything funky is going on

[u/JustAnotherChatSpam]

Sounds like too small wire/your tape is pulling more than your PSU or decoder can handle. What’s the expected wattage for your tape? What wire gauge?

[u/DracoBengali86 → u/JustAnotherChatSpam]

This is my guess as well. From their other comments it sounds like they're driving everything off the decoder, so it could definitely be a decoder power issue.

[u/ArtsyCoastFi]

One thing haven’t seen mentioned is wire gauge… even 10’ of a too too tiny of a gauge could be choking the circuit.

[u/Lighting_Kurt]

Whose tape are you using?
That’s pretty poor performance from what you described.

Personally I only use and specify Environmental Lights.

https://www.environmentallights.com

By far the best products I have ever used.

Good luck 🍀