Actual evidence to support the durability of LEDs.

[KevinNM]

I took a class from a Halcyon exec and for some reason we talked about LED lights. Essentially the issue with making reliable high power LED lights is heat. The emitters get very hot and the design of the heat sinks and other tricks to keep this under control is complex when you are going for high power long running lights. Though my impression is that the emitters won't get dim if you cook them, they will totally fail. I know some LED lights (tactical lights, not sure if SCUBA lights do this) have circuits that reduce the power to the LED as they get hot, so they will dim to protect the emitter. It seems possible that this kind of circuit, if this exists in your light, could fail and leave the light somewhat dim.

 

[tbone1004]

kevin, those circuits have to be built into the electronics and coincide with multiple brightness settings. I.e. on most of the backup lights, the UWLD lights, etc. when they start to detect increased consumption due to resistance from heat, they kick to the low brightness setting. If the driver doesn't have multiple settings, it can't kick down because there is nothing to kick down to. The heat sink design isn't really that complex, get as big of a chunk of metal as you can, preferably aluminum, and make sure it is touching the metal of the body in as much surface area as possible. If you make it out of delrin you're shooting yourself in the foot for use on land because it is an insulator and won't allow it to stay cool. That's why the UWLD's despite having a very small head, and generate heat that you can feel in front of the lens, stay very cool to the touch on the body because there is a lot of contact area.

 

[kelemvor]

Personally, I think you should consider there may be either a problem with the specific brand you chose or with what you are doing with the lights. I don't have any more data than you do really. I've got 5 LED dive lights, 3 of which are 1000 lumens. Two of them even came from eBAY for about $10. I've had most of them about 2 years, but one of them I've only had about 9 months. No problems with any of them. The closest thing to a problem I've had is I dropped and lost a DRIS 1000 on a dive.

I don't take particularly good care of them, and I've even used them as flashlights around the house for short periods.


Although this article is talking about car headlights, it does an excellent job at describing the technical superiority of LED over HID as a light source.

HID vs. LED Lighting - Innovative Lighting

 

[KDAD]

Tbone, unfortunately the manufacturer's provide very little information on their dive lights and the OP hasn't disclosed which one he's having a problem with so troubleshooting it is very difficult. iIt could very well be a failed component on the driver if it just suddenly started to dim and its not a battery problem

 

[runsongas]

kr2y5, can you disassemble the light head on either failed light? would be pretty quick to wire a 3v battery into the led to check if they work or not if you can. then you can pretty much narrow it down to either the driver or emitter.

 

[buddhasummer]

I've had three lights go bad, but it was not the actual LED but the electronics, nonetheless the result was the same, darkness.

 

[KDAD]

One of the lights is still under warranty so I suspect that it will be send back to the manufacturer for repair, if it hasn't already.

Kr2y5, if you want to send me the other light I can take a shot in the dark and see if I can shed some light on the problem (pun intended). PM if interested.

 

[kr2y5]

Thanks, guys.

The heat sink design isn't really that complex, get as big of a chunk of metal as you can, preferably aluminum, and make sure it is touching the metal of the body in as much surface area as possible.

If memory serves me well, in one of the links cited here earlier by lucca brassi, it was claimed that on average at least 50% of the contact surface between the radiator and the emitter is filled with air bubbles, and the more bubbles, the shorter the lifetime of the emitter. Maybe that's where occasional manufacturing defects come into play.

Personally, I think you should consider there may be either a problem with the specific brand you chose

I've always assumed that in the end, all those lights, regardless of the brand, are made up of components that come from the same factory somewhere back in China, is that not the case? Since the market is small, the light manufacturers presumably cannot afford having their own lab and developing their own hardware. I'm just speculating, though, I know nothing about it, and I might be wrong.

One of the lights is still under warranty so I suspect that it will be send back to the manufacturer for repair, if it hasn't already.

Yeah, it's been a couple of weeks, I haven't heard back yet, but I will share what I find out...

kr2y5, can you disassemble the light head on either failed light? would be pretty quick to wire a 3v battery into the led to check if they work or not if you can. then you can pretty much narrow it down to either the driver or emitter.

Kr2y5, if you want to send me the other light I can take a shot in the dark and see if I can shed some light on the problem (pun intended). PM if interested.

Thanks, guys, fortunately I haven't disposed of it yet, I will try to dig it out.

 

[runsongas]

there shouldn't be bubbles if an appropriate non-conductive thermal compound was applied between the emitter and the heatsink. same as why cpu heatsinks require thermal compound between the heatsink and the cpu.

 

[KDAD]

Dive light manufacturers do not make any of the emitters they use, nor the switches, reflectors, and most likely not the drivers as well. What they do do is design and have fabricated the housings and canisters and perform integration and assembly. They may build their own battery packs - it's just soldering batteries together in series and/or parallel.

The LEDs used in dive lights are sourced from Cree and Luminous. Both are very large manufacturers with pretty good manufacturing techniques and quality control. The LEDs used in dive lights are used in a variety of different applications and if there were issues with a particular manufacturer or type of led it would be widely known.

Since the emitter illuminates the problem is most likely in the driver or the battery. We would all be interested in what the manufacturer says was wrong if they actually tell you and not without glossing over the problem.

If the old light has the same symptoms whatever the manufacturer says is wrong with the warrantied light would be a good start in troubleshooting the other.

I've always assumed that in the end, all those lights, regardless of the brand, are made up of components that come from the same factory somewhere back in China, is that not the case? Since the market is small, the light manufacturers presumably cannot afford having their own lab and developing their own hardware. I'm just speculating, though, I know nothing about it, and I might be wrong.