# Short LED Life



## riderdan (Jan 2, 2014)

Hi all,

For those that light your buildings with LEDs, I'm wondering if you could estimate the life of them so I can ascertain if my experience an outlier or what...

I have numerous buildings on my layout that are lighted with LEDs. Generally I've bought these in bulk with resistors for 12v already soldered on. They're run about three hours a day off a timer. My oldest buildings have been outside about three years. That means that the total on time of the lights is about 3200 hours. 

Power is supplied by a Meanwell switching power supply, with the voltage pot adjusted to the lower end of the output--I'm measuring about 10.5v. Wiring is #12 copper direct burial cable to the buildings, then 24 ga copper inside to the individual lights.

The issue that I'm having is that in the course of the three years my Main Street shops and station have been outside, the LED brightness has dimmed significantly more than 50%. I brought one inside because I thought the electrical connections had gone bad. On my bench, I have another power supply and plugged the building in to do some troubleshooting. It turns out there's nothing wrong with the wiring, but some of the LEDs, you have to be looking closely, directly from the end, in complete darkness to see that they are, in fact, lit. 

My suspicion originally centered on the fact that these came direct from China via an eBay seller. But I've checked the resistors and they drop 12v to around 1.5v. Since the outdoor power supply is only pushing 10v, I don't think that the problem is too high a voltage. Obviously I don't have the lumen maintenance numbers on LEDs bought in bulk, but ~3000 hours is significantly less that I'd expect.

Does anyone have a similar experience, one that's wildly different, or any other theories as to why these are fading so fast?


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## toddalin (Jan 4, 2008)

riderdan said:


> Hi all,
> 
> 
> My suspicion originally centered on the fact that these came direct from China via an eBay seller.
> ...


Yes, you got it.

I bought a pack of 50 and made some decorative lighting with 5 in series. Only problem was that in no time some of them would go dim while others didn't. Eventually I got 5 good ones in there that have remained lit.


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## Cataptrra (Mar 16, 2015)

it all depends on how old your L.E.D.'s are. Originally L.E.D.'s had steel leads, these will rust and corrode over time, the rust can cause the dimming issues you speak of. If the L.E.D. can be picked up with a magnet, the leads are steel. Most newer L.E.D.'s have aluminum leads which don't rust, nor will a magnet pick them up. And the aluminum lead ones are much better for use outdoors.

I have had very similar experiences with L.E.D.'s in Christmas and Halloween strands, cause, socket and L.E.D. lead{s} had rusted, dimming the L.E.D. to look like it wasn't on unless you looked directly at it in a darkened room.

Best advice is, if you can them, find rust proof sockets and use them with your L.E.D.'s instead of soldering directly to their leads, also use some non-conductive paste, found at most auto parts stores, and coat the L.E.D. leads and the interior of the socket to help slow down and prevent corrosion{rusting away} of the leads and socket contacts. The paste I refer to is used in automotive sockets to keep them dry and from rusting out. You only need a very small amount, so a tube of this stuff will last you for years.

BTW: There are still millions upon millions of these old steel lead L.E.D.'s out there, against best way to see which are which is use a magnet to get the ones with aluminum leads, as the magnet won't pick them up!


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## Homo Habilis (Jul 29, 2011)

There is also lumen depreciation to consider.


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## Cataptrra (Mar 16, 2015)

**** Habilis said:


> There is also lumen depreciation to consider.


Can't say I've ever had that issue and I have some White L.E.D.'s that have been in railcars and loco's that I replaced back in 1997, and they are still just as bright today as the day they were installed. 

And these loco's, lighted cars have more hours than I know on them, now 2016, so they've been running strong for 19 years with no degradation.

And these loco's and lighted cars had been run for well over 6-10 hours a day/7days a week, sometimes even more.


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## Greg Elmassian (Jan 3, 2008)

did you measure the current the leds are drawing with your power supply? voltage really means nothing to LEDs, it's current.

Greg


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## JPCaputo (Jul 26, 2009)

I've had LEDs die after a short time when running them a bit too hot. Heat kills LEDs quick. If you can keep everything nice and cool they'll last longer.


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## Cataptrra (Mar 16, 2015)

BTW: I wire my L.E.D.'s in one of two ways, one way I use an LM7805 Voltage Regulator {+5vdc output} and a full wave diode bridge for passenger cars to keep the lights on in both directions, the anode lead{+} side of the goes to an 470 ohm resistor, 1,000 ohms{1K} here is overkill and will dim the L.E.D. just a little too much, 470 ohm makes a nice soft glow for passenger cars, but bright enough to see passengers inside. Also use this method for loco cab lighting. 

In loco's I usually wire the L.E.D.'s with an 1,000 ohm{1K} resistor in series with the anode {+} lead of the L.E.D. and no diode bridge. using track power this gives me directional headlamp capability, in reverse the forward lamp is off, going forward the rear lamp is off. Sometimes I'll use a full wave diode bridge on the front headlamp to keep it on no matter which direction the loco is heading, I usually only use this method with loco's that only have a forward headlamp.

Been using these methods since I got into the G Scale trains back in 1997 and I haven't lost any L.E.D.'s yet to date.


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## riderdan (Jan 2, 2014)

Thanks for the replies. I guess switching to sockets would at least make them easier to change out...


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## Cataptrra (Mar 16, 2015)

I use small 2 pin female sockets{connectors} with wires for most of my L.E.D. installs, then if an L.E.D. would happen to fail or I got hold of a bad one, or heaven forbid, I picked up the wrong color L.E.D. and installed it. Just too much work when repairs need to be made or want to change out the L.E.D. for another color, I use Super Bright White, Yellow, Red, Green and Blue L.E.D.'s for various things and once I find my buildings I'm still searching for, know they're here somewhere, I'll be changing their incandescent bulbs out for L.E.D.'s as well.

BTW: the 2 pin female sockets{connectors} come with wires attached and are the same kind found on MTH smoke unit boards. I get mine at an electronics surplus outlet between .15¢-.25¢ each. Occasionally they may cost a little more, but this is what I usually pay for them. Rarely I've paid as high as .50¢ each for them, but only if I really, REALLY needed them to complete a project. And on rare occasion I may find them bundled 50 for $5.00 or 100 for $10.00

And they've served me well for years since they are made to military specs for outdoor use and haven't had one rust away yet. L.E.D. leads yes, rust away, L.E.D. still good, but the rusted lead just falls apart because it's so brittle and make the L.E.D. unusable when the lead breaks off. 

And this is why I strive to get aluminum leaded L.E.D.'s over older steel leaded L.E.D.'s.


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## Rod Fearnley (Jan 2, 2008)

Dan I have suffered from the same things in the past. A friend of mine unconnected to the hobby, works on traffic lights systems on the highways.He told me to spray all of the leds and connections with clear auto lacquer. No probs any more.


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## Greg Elmassian (Jan 3, 2008)

I'm confused, the OP states the connections are fine, but the LEDs are dimmer.

This points to poor quality LEDs or over current. I gave suggestions to make sure the resistors on the LEDs are correct.

I'm not sure how corrosion figures into this, he has not stated there is corrosion.

Greg


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## riderdan (Jan 2, 2014)

The warm white LEDs are (supposedly) 3.2v at 25mA. I tore apart one of the pre-wired eBay ones and found what I believe is a 390 Ohm 1/2 watt resistor (OWBG). I think that's the correct resistor for these on a 12v supply--and as I said, my power supply is actually putting out 10.5.

I have had some with corroded leads, but those mostly went out completely. Those were almost all mounted on the outsides of buildings--they don't last long enough to go dim. The ones that were dim were from building interiors and seemed OK when I took a couple apart to see what I could see, and mainly were inside. At least, I didn't notice any visible rust.

I think I will probably switch to LED sockets, just so that they're easy to change out. Considering the low cost of individual LEDs, that's probably a sensible thing to do.


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## placitassteam (Jan 2, 2008)

I cut up strings of Christmas lights to use in my buildings. They have sockets and the lights are replaceable. Three in series will run for several days on a 9 volt battery. I haven't run them enough to determine if they get dimmer or die.


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## CliffyJ (Apr 29, 2009)

Dan, I wouldn't feel good about individual LED sockets, seems like an expense that's prone to corrosion and oxidation (on the socket side as well as the LED side). And you're still subject to the LED failure.

You might consider switching to waterproof LED tape, where multiple component LED's are doing the job. You can cut it every 3 inches (or thereabouts). At the cut line, you trim away the "waterproofing" silicone, and solder on your leads. The resistors are baked in (for 12v operation), and you can go many feet. Standard spools are ~16'. Many colors are available, and 3-packs of dimmers are cheap. You can also use a lower voltage power supply to power longer strips, for low-intensity but very distributed light, say, in a large building.

https://www.amazon.com/dp/B00HSF66JO

I haven't used these connectors yet, because I've only soldered my wires on. But I have some on order. They should eliminate the soldering. You can get packs of the male jacks really cheap.

https://www.amazon.com/dp/B0085ZX8EM

If you want to set the mood or disco up, the RGB kits are fun. The remotes are flaky & short range, but WTH, cheap thrills. I'd recommend to buy some, go out after dark, and just mess around. 

https://www.amazon.com/dp/B00ASHQQKI


Cliff


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## riderdan (Jan 2, 2014)

CliffyJ said:


> Dan, I wouldn't feel good about individual LED sockets, seems like an expense that's prone to corrosion and oxidation (on the socket side as well as the LED side). And you're still subject to the LED failure.
> Cliff


Cliffy--I can get the sockets for pennies each, and I've had good luck with my barrel connectors outdoors with a little Permatex bulb grease--some of them are three years old and still unrusted. So I'm hoping this might help in those situations where I have to have an individual lamp (light posts, wall sconces, etc)


CliffyJ said:


> You might consider switching to waterproof LED tape, where multiple component LED's are doing the job. You can cut it every 3 inches (or thereabouts). At the cut line, you trim away the "waterproofing" silicone, and solder on your leads. The resistors are baked in (for 12v operation), and you can go many feet. Standard spools are ~16'. Many colors are available, and 3-packs of dimmers are cheap. You can also use a lower voltage power supply to power longer strips, for low-intensity but very distributed light, say, in a large building.
> Cliff


I hadn't thought of that, but I do have a couple steps I bought a few years back for a different project, so I might try a strip or two of that out in buildings where I just need "general" lighting.

Originally I went with the individual LEDs as a cost-saving measure. When I first bought a set, I think I paid $30 for 100 of them. I am finding (as usual) that the trade-off for the low initial price is shorter life and other complications.


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