Cobs smoke
- Thread starter Budies 101
- Start date
Budies 101
Well-Known Member
I added them after I made the post, but it was shortly after.
Budies 101
Well-Known Member
Where is good places to buy heatsinks? I found some for the cxa3070 pin heatsink but I dont see any way to buy them lol.
Budies 101
Well-Known Member
thank you
weed-whacker
Well-Known Member
oh i missed those, well it looks obvious so probably wrong
YOU DONT HAVE A HEATSINK
dude, wtf really? what is that "metal backing" you used!?!?!? is it even aluminium?
how many fins?........looks like none
http://www.heatsinkled.com/Pin-Fin-Heat-Sinks-c24651876.html
Budies 101
Well-Known Member
robincnn
Well-Known Member
I will have 120's in stock in 2 days. Pre drilled for 3070. Should be good for 60W
Not sure why it's smoking. I ran a cob without heatsink once and saw smoke. Smoke was from the LES phosphorus burning up. made a pop sound within few seconds and silicone phosphorus LES was damaged followed by broken diode connections and the cob went out of action.
Not sure what grade steel or aluminum you using as heatsink. Steel does not look as good as aluminum in terms of thermal conductivity. cobs have concentrated heat so proper heatsink is important. The steel should still soak up some heat... Does the steel heatsink you have heat up right behind the cob atleast ? if it does not then i think thermal interface material could be the issue or may be there is some paint or something that is blocking the heat from cob to heatsink
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html
https://en.wikipedia.org/wiki/List_of_thermal_conductivities
Not sure why it's smoking. I ran a cob without heatsink once and saw smoke. Smoke was from the LES phosphorus burning up. made a pop sound within few seconds and silicone phosphorus LES was damaged followed by broken diode connections and the cob went out of action.
Not sure what grade steel or aluminum you using as heatsink. Steel does not look as good as aluminum in terms of thermal conductivity. cobs have concentrated heat so proper heatsink is important. The steel should still soak up some heat... Does the steel heatsink you have heat up right behind the cob atleast ? if it does not then i think thermal interface material could be the issue or may be there is some paint or something that is blocking the heat from cob to heatsink
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html
https://en.wikipedia.org/wiki/List_of_thermal_conductivities
Damn bro that's alot to invest without doing research you need to buy yourself 56 heatsinks
Budies 101
Well-Known Member
Well to be fair I built my first lights and it worked just fine. I did these lights different but it only cost me like 5 bucks for the case so buying heatsinks was something I always considered. I built my first lights like 8 months ago or so and knew nothing about LED's at all... I understood why you need a heatsink but as I said it seemed to work without it on my first build.
Budies 101
Well-Known Member
How much are they per?
I just bought some of the long flat fin heatsinks like what realstyles uses (dono how to spell his username). I bought 4 for veg lights that are going to be different than the flowering lights.
What size heatsink did you get?
robincnn
Well-Known Member
sixstring2112
Well-Known Member
i would think even thin steel would be good for 10 mins before it got too hot.im still guessing it to be too much paste or a wiring issue.if you ever looked at a mars panel,some of the leds are NOT mounted on the heatsinks,they are just on a flat piece of aluminum that is very thin.probably why those lights eventually fail but still mine ran for a solid 14 months lol.
SPLFreak808
Well-Known Member
With diamond style paste, adding to much will pro-long the break in period. Put that on a steel post and you'll probably see smoke. Do what these guys suggest and re-apply the paste lightly
Budies 101
Well-Known Member
Ok, when I get my new heat sinks I'll update just so everyone knows i didn't burn my house down and kill myself =)
welight
Well-Known Member
my first guess was the heatsink. While throwing lots of metal at a cob seems intuitive, the design of the heatsink and its ability to move heat through the sink is its key. The path to ambient is the rule of law with heatsinks and you need a path of least resistance which is difficult to achieve with flat bar, image below of our 140mm pin fins demonstrates what you need, an even spread of heat across all surfaces, if you can get the heat away, those babies will cook
Cheers
Mark
Cheers
Mark
coreywebster
Well-Known Member
Thermal Conductivity
Thermal conductivity (W/m K)*
Brass 109.0
Aluminum 205.0
Iron 79.5
Steel 50.2
Thermal conductivity (W/m K)*
Brass 109.0
Aluminum 205.0
Iron 79.5
Steel 50.2
Similar threads
