LED strip failure modes

Devices & Integrations
1

We have LED strips as cove lighting in the TV room (it’s too small to be a media room!).

It’s about 44ft of 3000K plain white 24V LED strips connected to a transformer and a dumb 3-way dimmer.

This is next on my list to make smart.

About a month ago, luckily before I changed anything, they started acting up. They would go out for a few seconds to a few minutes. Then back on for a while before repeating.

My question for the hive mind is: if there was a bad connecter between segments, would the entire length go out or just the part beyond the connector.

I’ve spent a good part of the afternoon climbing up and down the ladder poking at these damn things with no good diagnosis. For the moment they seem to be staying on.

Don’t dare introduce smartness while the basic functions are not 100%.

2

That symptom is usually one of two things:

One) too much load relative to the power source. This will cause overheating, the lights will shut off, they’ll cool down, they’ll turn back on, etc.

Two) the controller itself is failing.

There are other possibilities, but those are the most common.

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3

I’ll investigate that.

For what it’s worth, we moved into the house, newly built, in June 2018 and the lights have been fine until sometime in the last few months.

4

The strip is labeled “2.2w/ft” and the transformer is labeled 96W max.

I guessed the length at 44 ft, it is really just under 42 ft. So about 92.4 watts. Maybe pushing the transformer a bit.

There’s a cover over the wire connectors that I took off while checking connections. When I put that back on, the problem returned. Gonna leave it off for now.

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5

Sounds like it’s overheating. Some people find that this is more likely to happen in the winter when they are running central heating.

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6

Overheating seems possible.

Does not seem to be season-related. We’re in A/C season here in south central Texas, hit 98° once already.

My initial plan was to just swap out the dumb dimmer for 3-way Levitons. There are also 6 canless can LED lights in the room on their own 3-way.

I’d kind of like RGBWW LEDs so if I do that, I’ll bump up the capacity of the transformer.

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7

It could also be a loose connection in one of those wire nuts, especially if the problem manifested when you were taking the cover on/off.

8

I checked all four wire nuts.

I had previously even swapped out the dumb dimmer and have checked both sides of the 3-way carefully.

9

So the problem came back but this time the lights stayed off for a couple of hours.

I ordered a new 150W transformer. Because I had been searching, Google popped up with the article below which has caused me to cancel the transformer order.

https://www.power-supplies-australia.com.au/blog/meanwell-releases-best-dimmable-led-driver-led-strip

Extract from the article:

To acheive a satisfactory dimming result, LED drivers that do not have a PWM output need to be loaded up to their maximum capacity (PSA recommends 90~95%).

If the load is lower than 90% you most likely will find the dimming performance to be unsatisfactory.

10

Just to close this out.

The article about dimming sent me off on a chase. At first I thought I’d get a PWM dimmer with higher capacity. But reviews said they buzz. This is in our TV room and the driver sits in the ledge of the cove lights so buzzing was not desirable!

I ended up buying a replacement 96W non-PWM driver. Hooked it up today and so far it’s not exhibiting any problems.

It occurred to me: the existing setup worked flawlessly for about 2-1/2 years. It started having issues just after The Great Texas Freeze in February.

During that event we went thru a couple of days of rolling blackouts and then lost power for a couple of days when the substation had a failure.

Nothing else electrical in the house showed any ill effects but I’m now thinking the LED driver took damage from voltage fluctuations as power went off and on.

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