MC-E "Ugly" dive light--any other users?

I recently got a pair of these lights:

http://www.novaeproducts.com/apps/webstore/products/show/1557267

They are also found at DX.

I noticed that from charge to charge, the lights seemed to get dimmer. Like, fresh battery #6 was not as bright as fresh battery #1. It's not a battery problem, it's definitely the light itself getting dimmer with use. I had two lights, one with more use and one with less use, and the difference was easy to see when they were side by side. I also took measurements.

I got the "bad" light replaced and by the time the replacement got to me, the light that I didn't exchange was dimmer too... I had run a few more batteries through it. (Always in the water by the way, so no heat problems.) I exchanged bad light #2 and by the time ITS replacement got to me, the first replacement was dimming as well!

Anyway I am not trying to complain about the vendor, I am just curious if anyone has had a similar problem. If you don't have a pair of lights, or if you aren't in the habit of measuring the output, it would be easy to miss a 20-30% drop in power... one of mine is in that range, but another one lost HALF its light output--obvious even without a twin to compare it to.

Very curious!

Interesting.. Did you notice a coloration difference on the LED? This would indicate overheating. I have had a few LEDs that were not heatsinked properly do that! Overheating could happen, even in water if the LED is not set properly on the heatsink.

Nope, I did not notice a color shift.

Poor heat sinking was one of my thoughts too, but I didn't know that it could manifest that way. Makes sense though, good call.

+1, probably overheating

Looks like a faulty batch

Mine is still a bright as the day I got it.

Oh, BTW, by different coloration, I meant on the actual physical LED. Not the LED while turned on. The ones I have had that have failed, the LED turns a really darkish yellow color and the output goes down to about a tenth of the original. They still work just really dim.

have you read this thread ?
https://www.candlepowerforums.com/threads/227518

in my experience nearly all the lights purchased from DX dimmed. :shrug:
most causes were contact problem between battery and pill or tail cap spring.
only wiping these points clean by soft paper often improves brightness.
please try it if you have not done yet.

There is literally hundreds of posts on this light, not allowed to say where due to forum rules, just use the search function and google.

Thanks everyone.