What could make LED bulbs burn out?

GordonThree wrote:
in cold weather, my dc system is at 15 volts, my battery charger is temperature compensated. the cheap ebay panels I started with didn't last long. I have bad luck with stuff from ebay however.

Buy the Best and Cry Only Once....

in cold weather, my dc system is at 15 volts, my battery charger is temperature compensated. the cheap ebay panels I started with didn't last long. I have bad luck with stuff from ebay however.

I converted my entire MH, using cheap ($2-$4) eBay/Amazon LEDs from China nearly 2 years ago.
See this thread

48-5050 panels, 300 and 600-3528 strips, 5050 bulb style, etc. Use them boondocking on 12VDC as well as with full hookups (upwards of 13.8+VDC), in both cold weather and hot weather (115 degrees F). Haven't had a single failure. Wait, I take that back; I had a single LED in a 18-5050 bulb style go out in my porch light fixture.

Interestingly, I tested them running at 12VDC and 13.8VDC; very little difference in current, temperature buildup, nor even brightness.

Harvey51 wrote:
I noticed our SMD48 panels get hot when on shore power. I make a point of not using them when plugged in. We always boondock anyway. It is very revealing to connect a LED panel to a variable power supply and watch the current draw as the voltage is varied from 12 to 14. Over 14 they draw almost as much current as an incandescent and get almost as hot!

Then you are likely running regulator free LED's, or REALLY crummy regulators that were replaced several years ago.

I noticed our SMD48 panels get hot when on shore power. I make a point of not using them when plugged in. We always boondock anyway. It is very revealing to connect a LED panel to a variable power supply and watch the current draw as the voltage is varied from 12 to 14. Over 14 they draw almost as much current as an incandescent and get almost as hot!

oldbeek wrote:
I bought the cheap E-Bay bulbs and panels straight from China. My converter max volts is 13.8 No problems with mine after lots of hours.

I've done this twice now for 2 different rigs. No problems in the last 4 years.:h

4 years ago we bought ebay panels and the worse that has happened is the tape coming off. Now we do charge the batteries with solar in the day time and if we needed the generator it wouldn't be at night when the lights are on. So they don't see higher voltages.

That said I have had them running at 17v here at home and someone else tested them and didn't see a issue until 20v was reached. I even tested two in series on a 24v bank, they got hot but didn't blow.

I learnt this from my good friend who is a pretty good electronics guy, he had a company that manufactured electronic equipment for the Hollywood studios, synchronized 2 Arriflex cameras for 3D in the early 90's.

He told me this:

Transistors, transistorize
Capacitors, capacitate
Resistors, resist

And

DIEODS, die

With cheap LED'S voltage fluctuation and spikes even if you have a charger, many times when you turn on a 12v lamp there is a small voltage fluctuation, that is enough to damage the LED.

navegator

camperkilgore wrote:

2oldman wrote:

camperkilgore wrote:
Anybody have a written article or something to verify the oil from fingers problem?

google knows.

I googled the question quite a bit. Maybe you could steer me in the right direction.

I can't find a thing about touching LEDs, other than how to not get burned. The touching thing in regards to burning out a bulb is particular to much hotter bulbs, like quartz halogen.

So, given that nothing can be found on the subject, that leads me to conclude there's no truth to it. I looked on Snopes too, so it must not be a very popular myth.

GordonThree wrote:
None of the engineering papers I've read from Philips, Cree, Osram and others say anything about skin oils damaging the LEDs.

High power >500mW typically use a silicone encapsulant around the dice and plastic, glass or silicone lens. These devices are sensitive to pressure damage from touching the device.

Low power devices are mostly encapsulated in a high temperature rigid plastic epoxy .

Your knowledge of led's far exceeds mine, and it supports what I was thinking. Thanks.