Burning LEDs?

[Garycamper]

O what would cause a 12V LED fixture to burn out? One of my three LED done lights stopped working and some of the wires look burnt.

[Darwin Maring]

There was an overload and it pulled to many amps to burn the wires. Remove the LED and look to see if any of the components are brown/burnt.

Make sure the circuit it was connected to is fused or has a circuit breaker because it should have tripped the fuse/breaker B 4 burning the wires.

[Thomas G.]

If you ran the light with a charger running it could have gotten 14.5 or so volts, which can cause overheating. When I installed mine I installed inexpensive voltage regulators. I also fused them at 1 amp.

http://www.fiberglassrv.com/forums/f...tml#post293093

[Byron Kinnaman]

Little know fact. Simiconductors (LEDS are simiconductors) most common failure mode is to short, then burn open if there sufficient current available. In cheaply made fixtures there's no resister in series with the LEDs or voltage regulator. Therefore when one shorts the current increases to the point where it and maybe other burn open. Since the LED fixtures have the LED in series, like your older Christmas lights, none of them light.

Darwin, Most circuits have 20 amp fuses, even it had a 5 amp fuse the change in current from .2 amps to .5 or even 1 amp is not going to blow a fuse. Furthermore there's time vs current that determines when a fuse or breaker will blow. At double rated value that time is over 1 minute.

[fusedlight]

Some LEDs run very hot. Depending on the application that can cause failure of the LED.

[Ron F]

Tom has the key. When I changed my interior lighting to LEDs, I added voltage regulators to every fixture. Overvoltage, such as Tom described will cook your expensive LEDs.

I've also had experience with cheap (from ebay) LEDs that I purchased for my exterior light. For that one I neglected to add a VR, and that one burned out shortly after installing it. Smoked it... scared me. When my camper is plugged in to shore power, the converter will occasionally put out an equalization voltage over 14 VDC. I suspect that's why it burned out. After that exterior LED got baked, I replaced the old fixture with a motion sensing exterior light fixture (LED w/VR), that solved the problem.
Ron

[Per Walthinsen]

I've standardized on making fixtures from IKEA pucks, mostly because of the ease of mounting, ready local availibility, and the somewhat cooler color temperature that I like.

To control the voltage I use a "Meanwell" DC to DC unit from Jameco that will produce a tightly regulated 12v (adjustable, actually) with inputs from 9.2 volts to 18 volts. P/N 175805, 25.2 watt output. Even with significantly fluctuating input voltage the lights do not dim or flare up.

The usual switches I use are double-pole variants of some commonly used RV switches. Therefore, at the price of more convoluted wiring, the converter is activated right along with the lights and the whole thing is seamless in operation.

Most of these have been in operation for several years, with no hint of trouble.

[Darwin Maring]

Byron: I checked my converter and I have the blade fuses 20 and 15 Amp. I think I will get some lower ones as I have LEDs.

[Garycamper]

Turns out it was a manufacturing defect. Some of the resistors were bad. A new LED fixture works fine.

See my blog. Eggscamper.blogspot.com

[Byron Kinnaman]

Originally Posted by Darwin Maring

Byron: I checked my converter and I have the blade fuses 20 and 15 Amp. I think I will get some lower ones as I have LEDs.

You could lower the fuse size, but don't depend on it to protect over voltage to LED lights. Typically the engineering community jokes about simiconductor devices protecting the fuse. Meaning the device will burn out long before a fuse will blow. The fuse mainly protects you from fire, if more current is drawing through the wires than they're rated for they'll get hot and could start a fire. The smaller the fuse you can use the farther away from being able to generate high temperatures without blowing the fuse.