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UV LED strip light troubles Answered

Hey ho,

I rigged up a lighting display for some glow-in-the-dark memorabilia, using a 12V 5A power supply adapter (intended for LED strip rope lights) and some 5050 LED waterproof strips (trimmed down to 156 lights). I asked around and was told I didn't really need to add resistance so I just soldered them cleanly into the display and added an AC power switch between the plug and the power supply.

Everything looked fantastic for a few weeks, but over the last few days they seem to have faded... they are much closer to a mild, neutral white than the strong UV-only brightness they originally provided (fluorescent colors popped, GITD toys glowed nicely). There are a few places on the strips that have come to illuminate with a warmer, yellowy light. Before I purchase some new ones and prepare to replace these, is this a common issue with cheap light strings, or possibly something in the power supply I should check first? Do I need to add some resistance between the power supply and the lights?




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2 years ago

Thanks Jack! It does have the resistors along the length just as you say, but my memory of basic current made me wonder if I should have provided more resistance.

As a follow-up should anyone else encounter this: I found a leftover snip of the strip that I had cut off to fit and found that segment to glow as beautifully as the installed ones did at first, so it's clearly a matter of cheap LEDs losing their mojo (as opposed to the power supply). I'm ordering some new ones today from a reputable source and will use the first set as a test case. Which is good; I already know how I want to improve my layout... ;-)

Jack A Lopez
Jack A Lopez

2 years ago

I would expect this kind of LED strip light, intended for use with a 12 VDC supply, to have resistors built in. In fact, I would also kind of expect these resistors to be visible, and for there to be at least one resistor for every group of 3 LEDs. Often these kind of LED strips are made to be trimmed to length, as long the cuts are made in certain special places, usually between those groups of 3 LEDs, and usually there is a guide printed on the strip, for to tell you the allowed places to make the cuts.

In other words, I would expect that no external resistors are needed, because, you know, they're already baked into the cake.

I must admit, this is the first case I have heard of, of LED strip lights, self-destructing over a matter of few weeks, but that is not going to answer your question about whether this occurrence is common or rare, because I have relatively little experience with LED strip lights, and I haven't seen everything under the sun.

Although maybe I could come close to a level of godlike clairvoyance, seeing and knowing everything, everywhere, just by using a search engine.

Well, I guess anyone can do that. ;-P

Anyway, my best guess advice is that you, in the future, do NOT again buy this particular brand of LED strip lights.