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Forum topic by Zonker posted 11-14-2019 09:58 PM 545 views 0 times favorited 14 replies Add to Favorites Watch
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Zonker

108 posts in 413 days


11-14-2019 09:58 PM

Topic tags/keywords: question resource tip

I need advice, I have 7 4’ LED shop lights hard wired into my shop. All wiring and the lights themselves are new construction, as of 1 year ago. About 5 months ago I had to replace one of the fixtures due to flashing. They came in packages of 4 lights so I had a spare on hand. Now I have a second fixture flashing in a different location (meaning not the same spot the first one crapped out in). The overheads are ganged in two sets of three and a single one in between. All my overheads are on the same 20Amp circuit, the only other things on the circuit are the exterior lights (LED bulbs in standard fixtures on motion sensors). I’ve found some YouTube videos and websites, but they all seem to be speaking greek. I’m thinking my drivers are cheap and going out. But before I start replacing things, I want to know a few things.
1. If I had surging or intermittent power, would it affect just one or all if the fixtures?

2. Is there a reliable way to check for surges/intermittent power with a basic multimeter?

3. If I end up replacing them, who can recommend a good hardwired linkable replacement.

Thanks in advance for any help.

-- Larry A. - I've made a small fortune with my woodworking. The trouble is, I started with a large fortune.


14 replies so far

View RDan's profile

RDan

126 posts in 2886 days


#1 posted 11-15-2019 12:07 AM

This is usually caused by the LED’s going bad. I have found that a bad power supply or a deterioration of the LED connection in the circuit can cause this. It will depend also if you have them in series or parallel. Most LED’s are hooked in series for a strip. Think of each one as a resistor in the circuit. You can check for a voltage drop across each on to see if it is consistent. Dan

View therealSteveN's profile

therealSteveN

4318 posts in 1136 days


#2 posted 11-15-2019 05:08 AM

Electric lighting is getting crappier all the time. On an LED they aren’t much except a circuit board. Cheap circuit board fail early, and often. I think at least at present the here and now, and foreseeable future is around LED lighting for low cost, and high output. I may be all off here, but I only buy ones with a plug, and I get them as cheaply as I can. So when they do fail, I unplug, rehang, replug, and done…

Really unfortunately this Summer we had a lightening strike. Wanna talk about losing a LOT of LED’s at once, they apparently do not like surges very much. Going forward we are now armed with a whole house surge protector, who knew….

-- Think safe, be safe

View ibewjon's profile

ibewjon

1068 posts in 3355 days


#3 posted 11-15-2019 10:16 AM

Yes, a multi meter might detect a surge. And you might see it if you watch the meter 24/7. Put in a surge protector on your incoming power. Connect it to the first breaker near the main. And if you have a panel in your shop, add another one there. I have had good success with square d brand.

View Brawler's profile

Brawler

90 posts in 392 days


#4 posted 11-15-2019 11:35 AM

To answer your questions:
1) Possibly, electronic devices have tolerances and one light could be slightly different than the next.
2) Probably not
3) I used these https://www.amazon.com/gp/product/B073W21P6X/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1 in old rewired fluorescent fixtures. They are bright, frosted so no harsh shadows, and they are good from 100 volts to 277 volts. I have been very happy with them. Hope this helps.

-- Daniel

View Fresch's profile

Fresch

455 posts in 2483 days


#5 posted 11-15-2019 03:35 PM

The junction (connection) point of the LED itself has a thermal limitation, most likely your problem is cheap drivers (the power supply from incoming voltage to the voltage driving the LED).
I did a major renovation of LED fixtures using, you’ve seen the lighting on tv if you watch football, we had some bad flashers and I opened one up to find the driver had released from the heatsink (the fixture wall) as nay being held by double sided heat transfer tape.

View JayT's profile

JayT

6325 posts in 2773 days


#6 posted 11-15-2019 03:46 PM

Agree that it is either circuit boards or drivers going bad. The biggest difference in cheap LED bulbs and fixtures vs quality ones is how well the circuit boards handle heat. Better connections, thicker wire and adequate heat protection add to the price—the diode itself is almost never the problem.

We’ve redone the lighting in several of the stores where I work and even with good quality LED tubes, there is about a 5% early failure rate. It’s much, much higher with cheap ones.

When you replace, just keep in mind that similar to tools and many other products, you get what you pay for. Not saying you need the most expensive lighting, but it is necessary to match product to use.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

View splintergroup's profile

splintergroup

3064 posts in 1784 days


#7 posted 11-15-2019 03:50 PM

Either a thermally intermittent solder joint on one more LEDs or (most likely) the power supply (driver) is going into a current limit shutdown from a failed driver component or as Jay mentions, bad heatsink connection.

View DrTebi's profile

DrTebi

360 posts in 3829 days


#8 posted 11-15-2019 07:44 PM

I would guess that the LED tubes have gone bad. I have had one that started flickering as well, while all others were fine and still are two years later.

I have been a big fan of LED lights and started replacing pretty much every light in my apartment and shop 10 years ago. There weren’t many companies out there making LEDs, choices were limited. The only LEDs that are still working fine today are my Philips EnduraLED tubes in the workshop, some lightbulb replacements from Philips, and Cree LED cans in my kitchen.

If you are planning to replace your tubes, I can highly recommend the Philips tubes. You may get lucky with cheaper ones, but oftentimes it’s the same old story… you get what you pay for.

View Zonker's profile

Zonker

108 posts in 413 days


#9 posted 11-17-2019 01:51 PM

Thanks Everyone. I have removed the offending fixture, and will be ordering up a Quantity of replacements. The lights I have consist of a strip of LEDs and the driver in a metal body with a lens. The wiring is all soldered between the driver and light strip. They “gang” together at the ends so there is no rewiring.Again, thanks for all your advice.

-- Larry A. - I've made a small fortune with my woodworking. The trouble is, I started with a large fortune.

View clagwell's profile

clagwell

56 posts in 354 days


#10 posted 11-17-2019 02:14 PM

Zonker, do your fixtures hang from chains or are they attached directly to the ceiling?

-- Dave, Tippecanoe County, IN

View bondogaposis's profile

bondogaposis

5570 posts in 2913 days


#11 posted 11-17-2019 04:29 PM

Since you already have a strobe light you may as well put up a disco ball.

-- Bondo Gaposis

View therealSteveN's profile

therealSteveN

4318 posts in 1136 days


#12 posted 11-17-2019 08:43 PM



Yes, a multi meter might detect a surge. And you might see it if you watch the meter 24/7. Put in a surge protector on your incoming power. Connect it to the first breaker near the main. And if you have a panel in your shop, add another one there. I have had good success with square d brand.

- ibewjon

Yes, this is what my Electricain did. Cost us 300 bux installed, carries a lifetime 45K guarantee. So far the Electical strike has gone over 8K in total destruction, and items that “kinda worked” afterward. Insurance is still looking, but I’m thinking I own a portion of it.

-- Think safe, be safe

View Zonker's profile

Zonker

108 posts in 413 days


#13 posted 11-18-2019 02:03 AM

Dave, The fixtures are attached to the ceiling.
therealsteven: Were all your LEDS flashing/failing after the surge? or just a few.

-- Larry A. - I've made a small fortune with my woodworking. The trouble is, I started with a large fortune.

View clagwell's profile

clagwell

56 posts in 354 days


#14 posted 11-18-2019 10:48 AM

All of the low cost shoplight style fixtures I’ve looked at have the heatsink on the top surface and rely on natural convection for cooling. If the fixture is mounted against the ceiling the airflow is interrupted and all of the electronics are forced to operate at a higher temperature. Aging rate increases (lifetime decreases) exponentially (roughly a factor of two for every 10C) with temperature.

Some of those shoplights include warnings against ceiling mounting, just like many LED replacement bulbs are not rated for use in enclosed fixtures.

Can you estimate the number of hours per day those lights are in use?

Bottom line: A LED bulb in an enclosed fixture or a shoplight attached to the ceiling will fail sooner than one that has better cooling. That happens even if the device is rated for that environment. The rating just means that the thermal design has enough margin to delay the failure past the warranty period.

-- Dave, Tippecanoe County, IN

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