LED Repair

[Steve@Advance]

About 6 months ago I upgraded 6 of the 8' 2 lamp Slimline light fixtures in the shop.

Now, they are already failing!

These are the type with built in power supplies, operate on line voltage. They are the double strip LED's, 75 watt by the label.

I took 2 of them apart yesterday. Each lamp has 2 power supplies, both showed the same problem, a micro-mini transistor was the center of a blackened mass of carnage!

I was able to remove one good power supply and transplant it to the other lamp to make one good one, but even the good supply showed signs of running hot, so it's just a matter of time before they all fail.

While I had it apart I checked the voltage output. To my surprise the voltage was up around 70VDC. I thought LED strips ran on 12v or 24v, but not these.

I guess it's a far stretch to try to save these...

 

[Janicholson]

let us know the manufacturer/brand so we can avoid them. Jim

 

[Steve@Advance]

No brand I've seen.

Ebay, Hecho en Chine...

 

[Janicholson]

that right there might be a substantial part of the story. You might try to keep them cooler, maybe a hole in the reflector to let air get past them by convection. Jim

 

[guido]

Hello Steve@aAdvance,

Good know what to avoid. Operating voltage depends on how many led's are in series.

Count how many led's there are, and with the operating supply voltage decided by the # of led's, you will find out how much a single one takes to make light, more or less

Guido.

 

[Steve@Advance]

Guido, these don't appear to be in series, but in parallel.

I installed LED tape lights under the kitchen cabinets, they were 24VDC regardless of the length. I did have to multiply the length to get the amp load for the power supply.

I have a feeling the voltage can be pushed to get more light at the sacrifice of longevity.

Since the weak point of these is the power supply, makes me rethink the ones that run off the ballast might not be such a bad idea.

I have no idea what voltage a ballast makes or if it is AC or DC.

 

[wore out]

"To my surprise the voltage was up around 70VDC."

I have some fairly new LED street lites that failed and the power company scrapped them, and I got several from the scrapyard.

They are are 71 Watt LED and use a 300 VDC power supply (yes, that's correct) and all except one had a failed power supply, the other had a bad connection in a multiple pin plug.

The good power supply will light them all up, the actual LEDS are good in all of them.

But try to find a power supply!

LEDS typically use a constant-current power supply, the voltage is varied to keep the current constant to avoid overheating them as otherwise the current would rise as they heat up until the smoke was let out and I have not been able to find a generic replacement.

It seems that through the company (if you can even actually get them) they are the better part of the price of a complete new unit.

So the power Co. scraps them at the first sign of a problem and replaces the entire unit, mount and all, with a new one.

https://www.cooperlighting.com/cont...ark-caretaker-features-benefits-sellsheet.pdf

"Caretaker LED streetlites"

 

[cannonball]

I got some of these
Untitled URL Link

 

[showcrop]

You want ballast bypass.

 

[M-MAN]

Been hearing of that happening to often with the shop lights. Think I'll stick with the 150 watt equivalent screw in bulbs.

 

[c.oawright]

(quoted from post at 22:16:06 12/18/20) About 6 months ago I upgraded 6 of the 8' 2 lamp Slimline light fixtures in the shop.

Now, they are already failing!

a micro-mini transistor was the center of a blackened mass of carnage!
.

They are designed to fail.

The time life designers will work on it till they can get them to last enough hours to keep customers somewhat satisfied.

The tungsten fulfillment in a regular light bulb time life is about 1000 hours on the nose. Its based on duty cycles on and off. The filament flexes back and forth due to thermal expansion and contraction until it breaks.

Components in the LED designs have similar features. Things like the transistor that was undersized in its current handling ability or resistors to small wattage wise and fail with heat cycles.

 

[showcrop]

(quoted from post at 06:43:37 12/19/20)

(quoted from post at 22:16:06 12/18/20) About 6 months ago I upgraded 6 of the 8' 2 lamp Slimline light fixtures in the shop.

Now, they are already failing!

a micro-mini transistor was the center of a blackened mass of carnage!
.

They are designed to fail.

The time life designers will work on it till they can get them to last enough hours to keep customers somewhat satisfied.

The tungsten fulfillment in a regular light bulb time life is about 1000 hours on the nose. Its based on duty cycles on and off. The filament flexes back and forth due to thermal expansion and contraction until it breaks.

Components in the LED designs have similar features. Things like the transistor that was undersized in its current handling ability or resistors to small wattage wise and fail with heat cycles.

Coaright, I suppose that you own a business and have found that somewhat satisfied customers is the best path to success??

 

[Janicholson]

Mean time between failure (MTBF)is always on the butcher block. Engineering things to make customers feel they were satisfied has been a sacred tradition. General Motors had no Idea the 51 3/4 ton PU I own would still be operational. There are good reasons to make efficient long lasting well designed products. As we (humans) choose how we treat the planet, and our children's future, we must trend toward actual conservation. Jim

 

[Blackhole49]

A 1 1/2 years ago I upgraded all my 4' florescence fixtures (48) in my shops and basement to 4' Sunco LED. Absolutely love them and so far no problem. Really like the instant on in my unheated (SE MI) barn.

 

[Steve@Advance]

Yes, ventilating them might help.

Not only are they enclosed inside the aluminum extrusion, the power supply is wrapped up in a piece of cardboard to keep it from shorting against the aluminum.

I could drill some holes, and remove the cardboard, support it by the ends so it couldn't touch...

Thanks!

 

[guido]

Hello Steve@ Advance,

There most be a series circuit adding up to 24volts then. Who knows what the land of almost right is doing. I know what they are not doing, designing their own stuff, copy cats!


Guido.

 

[c.oawright]

(quoted from post at 10:29:39 12/19/20)

(quoted from post at 06:43:37 12/19/20)

(quoted from post at 22:16:06 12/18/20) About 6 months ago I upgraded 6 of the 8' 2 lamp Slimline light fixtures in the shop.

Now, they are already failing!

a micro-mini transistor was the center of a blackened mass of carnage!
.

They are designed to fail.

The time life designers will work on it till they can get them to last enough hours to keep customers somewhat satisfied.

The tungsten fulfillment in a regular light bulb time life is about 1000 hours on the nose. Its based on duty cycles on and off. The filament flexes back and forth due to thermal expansion and contraction until it breaks.

Components in the LED designs have similar features. Things like the transistor that was undersized in its current handling ability or resistors to small wattage wise and fail with heat cycles.

Coaright, I suppose that you own a business and have found that somewhat satisfied customers is the best path to success??

Nope... Worked in the labs where they do it.