Burned P7 up close

[walmartshopper]

I had the driver go bad on my new MTE P7, so I ordered a new one and did a quick direct drive mod in the meantime. It was getting hot pretty fast with a fully charged battery, so I was trying to get the battery down to around 3.7v by turning the light on for a few minutes and then letting it cool. One of the times though, I got a call that required my attention elsewhere and distracted me for about 15 minutes. When I ran back upstairs, it was already too late, and the LED was damaged. One of the four cores was completely burned out, and two other cores had small dark spots. The core that was burned out did not show any visible damage. It's still pretty bright, but the dark spots are growing slowly, and I'm guessing they will eventually cover the entire core. I have a replacement P7 DSXO on the way, so hopefully with a new driver and emitter it will be a decent torch.

The dome was scuffed when I got it, hopefully the replacement will be better

Still pretty bright for the amount of damage:

The beam is still good but the hotspot is slightly oval shaped

 

[waddup]

nice macro work:thumbsup:

 

[DM51]

Welcome to CPF, walmartshopper

That's bad luck damaging your LED, but you've realised how it happened and you seem to know how to replace it.

Those are very interesting photos, and an excellent illustration of the damage that can happen to an LED when it is overdriven - something that I think happens more often here than people report.

I'm going to move this to the LED (emitters) section, as it will be of interest there. Thanks for a very good 1st post!

 

[rizky_p]

First post and with a Bang thanks for sharing it with us. Never seen a burned p7 myself....I am sure with the knowledge you have you are not completely new to CPF aren't you?

 

[walmartshopper]

I'm new here, and this is my first flashlight in probably 6 years, although I've been lurking for about a week and learning as much as possible.

My EDC light has been a CMG Reactor the whole time, which I think was a first gen luxeon (trustfire XP-EF23 is on the way for a new EDC). I was out of the loop and didn't realize how far LED emitters had come. And then my mom got me a Streamlight Nanolight for christmas, and with 4 LR41 cells it was brighter than my CMG with 2xAA lithiums. So anyway, I started becoming interested in the newer LEDs.

I'm a computer technician and programmer, fairly familiar with soldering, and with basic electrical knowledge, so I figured I would start with a budget P7 light and work on it if needed as a learning experience. I was a little disappointed to find out that the area around the emitter was filled up with glue, and I had to scrape it all out before I could even replace the wires. Long story short, the 5 mode driver degraded into a 2 mode low+med driver, so I modded to direct drive, burned the LED, and now I need to replace both. Before I drop in the new emitter, maybe I'll see if I can burn this one out completely and post more pics.

 

[walmartshopper]

I managed to burn another core (on purpose since I have a new emitter on the way). Interestingly enough, the two cores that are completely dead now are the ones that don't have any visible damage, while the two cores that are burned and cracked are still working. Here's a new macro of the two burned cores still working:

Edit: Actually, the third core lights up for about 5 seconds, flickers a little, and then goes dark while the other two remain on but are not putting out much light. I'm getting maybe 50 lumens total from the two cores with the brown spots.

1/4000, F32, ISO100, 60mm

 

[walmartshopper]

Another with the dome removed:

 

[tebore]

This is a perfect example of how an less stable phosphor combined with a relatively poor thermal pathway gives little headroom for overdrive.

This is relative to the MC-E of course and even the new SSTs.