C6 Host DOUBLE M140 Duty Cycle

[SKeeZ]

Hello LPF,

Today I have discovered something fairly interesting. One of my previous hobbies was RC cars. I had an RC car called the MLST/2 which had a dual motor configuration.
These motors would get VERY hot and thus needed heat dissipation.

Earlier i decide to take those heatsinks off of the car and put them on my C6 2Watt laser with no real hope that it would actually fit. Miraculously, the things clipped on
solidly and after some testing, i found they increased my duty cycle of room-95 degrees in 1 minute 7 seconds to 1 minute 47 seconds.

I was pretty impressed so i though i'd share. if your interested you should be able to find them by the search terms "Losi Losb0834" here are some pictures:

 

[benmwv]

Im not sure where you are measuring the temp at but just because it takes that long for the fins to get to 95 doesnt mean it takes that long for the diode. There are a lot of thermal resistances between the diode and the fins. If you aren't already you should measure the temp of the module when you are finding your duty cycle.

Good find though!

 

[SKeeZ]

300th Post

yes, i was measuring the tempeature of the inner heatsink with an infrared thermometer for both tests so thermal resistance was not a variable introduced on the second test.

 

[benmwv]

Good! A lot of people just wait for the outside to feel like its too hot, and by that time the diode is way too hot.

 

[SKeeZ]

yeah... i'm not that dumb.

 

[Tmack]

Looks pretty sick too. I'm liking it. Gotta love it when an crazy idea turns out to work.

 

[SKeeZ]

for sure! you may want to contact coldshad0w about merging your old and new accounts BTW. you'll get all that hard earned rep back aswell as your post count. i did the same.

 

[Tmack]

Don't really want it back. Doesn't really mean anything does it?

 

[SKeeZ]

somewhat... i'd rather take advice from someone with high rep...

 

[Tmack]

That's true. Well I'm the one looking for advice! So a high rep on my part would be misleading lol

 

[SKeeZ]

true.

 

[Cyparagon]

Good! A lot of people just wait for the outside to feel like its too hot, and by that time the diode is way too hot.

The thermal resistances involved are not high enough, nor is the net heat dissipation high enough for that to be a valid statement.

I'll never understand why over-driving the piss out of diodes is perfectly acceptable, but God forbid they get to 50C.

 

[benmwv]

In a lot of hosts there is pretty high thermal resistance between the diode and the outside of the host. Especially when a nickel plated brass module is in the heatsink with a set screw instead of press fit and the heatsink is a bit loose in the host and there are up to 4 anodized surfaces between.

You have a thermal camera correct? Have you viewed a running high power laser from it, with the lens removed so the module is visible? I can easily feel the heat difference with my finger between the module and outside of the host on most lasers. Thats not a quantifiable measurement though.

You want to keep the heat down so the diode doesnt die. I thought this was a fairly simple concept? Yes, overdriving reduces lifetime, so why reduce it more by running it to high temperatures?

That said, I do have a c6 laser with an m140 running at 1.8A that I totally disregard the duty cycle on. Once I got a slight burn (melted the pattern in my skin) from touching the lens nut which is in decent thermal contact with the module, the outside of the host was fairly hot but not close to burning hot. The diode doesnt seem to have any major degradation. Just because this one diode hasnt died yet doesnt mean I can recommend that to everyone though. Its best to keep the diode (not the outside of the host) at a reasonable temperature so you dont risk any more reduction in lifetime.