LED Abuse

[lonesouth]

Shortly after I got into LEDs, I decided I had to have a Cree XR-E R2. I got this LED and was still using a combo of JB-Weld and Actic Silver CPU compound. Not too long after I had, what I thought, thoroughly destroyed this LED. I managed to rip off the dome and severely chew up the mounting star. I used my bench grinder/wire wheel to remove the J-B weld mix and during testing, the LED got hot enough to desolder itself. I used excessive heat to finish removing the LED from the star and put both in my parts bin figuring both were a loss.

I came back to this LED while waiting on my DX order. I used more excessive heat, pliers and dropping the star to remove the rest of the solder. I did the same with the LED. Then I managed to solder the LED back to the star without creating a solder bridge from the slug to both pads. Mounted this to 1" of 3/4" aluminum square tubing. Taped that to an old Motorola switching phone charger 375ma, tape going through the tubing and around the charger. Clipped the wires to just long enough and plugged it in. I couldn't believe this abused LED still had it. It works as an excellent night light if used an indirect location. I'll snap some pics tonight, but I figured I'd see how you guys have abused LEDs and been surprised when they still worked in spite of your best(or worst) efforts.

 

[bshanahan14rulz]

I have a cree LED that is nothing more than the ceramic substrate, SiC diode, and LED chip w/ phosphor. All 4 bond wires intact. Only a little gel on one corner of the chip under a bond wire. No cree ring, no dome. Very bright, no difference in color, afai can tell. Trying to mount it in a p60 drop-in to see what kind of beam pattern it gets. Need a star, though. DX, here I come! (well, after I get paid. can't even afford an effing chunk of aluminum >.<

 

[lonesouth]

Quick update. This light has been in use for ~12 hours a day for the last 11 months. It is still plenty bright and has never shown to first inkling of trouble. I'm betting that the timer or charger will fail before the LED will.

 

[Axkiker]

I agree LEDS can take more than people think


I have 2 sets of leds running straight off my boat battery and have had no trouble. I figured with all the talk you hear about transient voltages, reverse polarity and voltage spikes they would have been toast a long time ago...


still runnin

 

[Steve K]

it's a matter of probability. If you are building just one copy of the design, and it's no big deal if it dies, then you can cut a lot of corners. If you are producing 100,000 a year and even 0.01% die early, then it's expensive to replace all of the parts and compensate the customer (assuming that you want to keep the customer happy). And if someone gets hurt because your product failed at a bad time, then things really get pricey!

So, there are reasons to protect the LEDs. It's up to you to decide if it's worth the extra $0.20 of parts.

regards,
Steve K.

 

[CKOD]

Nice work with the charger/LED, I have a few old chargers around that look like they might have found a use!

I agree LEDS can take more than people think


I have 2 sets of leds running straight off my boat battery and have had no trouble. I figured with all the talk you hear about transient voltages, reverse polarity and voltage spikes they would have been toast a long time ago...


still runnin

Automotive systems are tough, especially with load dumps etc, but if youre hooked up right at the battery, the battery can be what protects you, you figure an automotive battery can output 500+ A (and presumably sink that much too on severe overvoltages) any sort of transients would be absorbed by the battery. It can be quite different once youve gone though 2 fuse panels supplied with wiring thats a slim as it can be and still be reasonably safe (you hope) and you have a load dump which causes an overshoot.

Plus I'd imagine a smaller boat could have less electronic widgets to cause problems.

 

[MikeAusC]

I've replaced the five interior lights in my 2007-build car with LEDs.

Just the cheap multi-LED boards - strings of 3 white LEDs and a resistor in series.

2 years later still working fine.

 

[corvettecrazy]

I agree. I have run the bulb pictured below for almost a year now in my map lights. LM317 as a current regulator with the 3 XR's running at 350mA. There is no heat sinking at all and it isn't uncommon for it to flicker as the LM317 bounces off the thermal shutdown. Still going strong!

I've also taken an XP-E soldered wires to the +/- pads and ran it at an amp. After it heating up enough to de-solder the wires 3 times I got sick of soldering them back on and tossed the LED.