Humple
Well-Known Member
Yet many of the dudes who buy their QB knockoffs insist that they wouldn't cut corners, and that anyone who buys HLG's boards is getting ripped off. Go figure.
OOPS.... Burnt Cob of Corn (Minus the Corn)
- Thread starter Joint Monster
- Start date
GBAUTO
Well-Known Member
They run @ 50degC based on IR temp readings with normal airflow in the room. That's running the Veros @ 80w.
Joint Monster
Well-Known Member
Ah I found them. These ones:
SUR-SEAL SUR-COOL THERMAL PAD
I used arctic thermal with computer stuff before so yeah, that would be my other option, if these are not suggested?
I purchased it from one of the more reputable people/sites. They may have an account here to. I don't want to oust them, as I don't truly feel they did anything wrong. (Then even if they did send me wrong sized heatsinks, I would still be at fault for not knowing and purchasing.)
I had bought them as a "Kit", I chose to "customize" it by asking for different Cob models and Driver Model. I was given the wiring, wago's (although I opted to solder where needed on the driver), the thermal pads came with it to.
I'm going to say be optimistic and say there may just be an issue with adhesion. I did have issues where some pre-drilled holes were not long enough for the screws (so I used different holes), one screw broke in the hole... so yeah maybe I should get a torque screw driver while I'm getting the temp reader. -.-
To replace all the heatsinks would be the very top end of a 3 digit price tag. @GBAUTO is saying he has the same thing as me and running them without any issues. (So I'll hope that it's just that. I'll go back and fix all the screws again, then run them and get a temp reading and see. I will still have to order new cobs though.)
Current setup:
Cobs (5K 70CRI D and 3K 80CRI D) (I'm not exactly sure which ones are the ones affected. They have the same specs.)
Typical: 2100mA (37.6V)
Max: 4200mA
Driver:
Mean Well HLG-480H-1750B
Output V (DC): 137 - 274V
My Cobs in series, 6 Cobs (per driver) @37.6V = 225.6V. (isn't that okay with this driver? Or do you mean that having them setup in a series is a dangerous amount of electricity?).
This was my first go at LED, I just jumped straight into the deep zone. (I really Appreciate ALL the help everyone gave me getting it up and running! <3)
I didn't use any lenses. I mounted them directly onto "L" metal brackets. Also added an extra "ground" wire from the frame to the driver.
Airwalker16
Well-Known Member
Well 80 watts is asking a lot from that sized sink man. That's why I said if young's direct fan air movement directly across all 12 of them, you can probably get by. I would use the dimmer a bit if you can't get the air movement situation figured out. That will help immensely.
Chip Green
Well-Known Member
I see 1750ma CC drivers running 36v COBs, that's 65w....not sure where the 80w is coming from.
To have a series build with that level of forward voltage, brings the risk of a potentially lethal mistake. Many have chosen to avoid this hazard, by wiring in parallel, with CC/CV drivers.
Just know and understand, that the total voltage output of those particular MW drivers you are using, does have the capability of delivering a devastating jolt.
To have a series build with that level of forward voltage, brings the risk of a potentially lethal mistake. Many have chosen to avoid this hazard, by wiring in parallel, with CC/CV drivers.
Just know and understand, that the total voltage output of those particular MW drivers you are using, does have the capability of delivering a devastating jolt.
Airwalker16
Well-Known Member
I didn't really pay attention to the current I guess just did 480/6. My bad
Pioneer and Sansui ...
GBAUTO
Well-Known Member
I can tell you from experience that the sink/cob/driver combo he's using is more than adequate thermal management. I run oscillating fans in my space-nothing blowing directly on the sinks and they never exceed 50 degC with my IR temp gun. Also, after realizing that he's running them at lower power levels than I ran all last year, the problem is bad conduction-poor TIM application. Replace the damaged cobs and use better technique
Last edited:
nevergoodenuf
Well-Known Member
I have tested a couple thermal pads vs. arctic silver 5 and the pads were garbage. They require more pressure than some of the holder will allow. On the 600w heatsink, you will see that the thermal pads did almost nothing. I will say that the citizen COB can take some heat (270+*c) and it still works.
welight
Well-Known Member
couple of things to consider
Cheers
Mark
- Thermal Paste, grease, compounds: read the data sheets you need to balance thermal performance vs potential messy process, the number you want is Thermal Conductivity: more is better
- silicon pads are good, we have one that is Thermal Conductivity:8.0 W/m.K, thats twice the conductivity of Arctic Sliver Alumina, however when you pull the adhesive covers off, the material can break so place one side on the COB first before removing back cover
- Graphite pads are also Thermal Conductivity:8.0 W/m.K, but thats in the vertical, in the horizontal they are Thermal Conductivity:20.0 W/m.K, in other words once the heat is driven down it is spread nearly 2.5 times more effectively
Cheers
Mark
Airwalker16
Well-Known Member
Lol so graphite pads are the best by a LONG shot.
welight
Well-Known Member
on paper thats how it stacks up
Airwalker16
Well-Known Member
welight
Well-Known Member
Hi Airwalker
sure we can help, do you have a zip code, or PM it if you like, I will check cheapest postal cost,
Cheers
Mark
Randomblame
Well-Known Member
On paper graphite seems superior but that's only in theory. Especially at higher currents they are overwhelmed and can not keep up with a good thermal grease/paste. See the tests @nevergoodenuf posted above.. He has a lot of experience with 250 to 500w COB's.
Btw..
What's going on in your high powered garden, mate? Still growing vertically?
Btw..
What's going on in your high powered garden, mate? Still growing vertically?
nevergoodenuf
Well-Known Member
@Randomblame I just got to busy to post lately and it seemed like I was just posting the same things. I have a 2'x8' tray that is vertical, but the rest of the room is just 3 3'x3' trays now.
Randomblame
Well-Known Member
Hehe, yea! Isn't it not always the same..? But we all love to watch pics and your garden was always something special as you use high powered single COB's like "real" HPS replacements and it works out great.
welight
Well-Known Member
I cant comment on that as Im basing this information on the 75-80 watts being discussed here. not 250 watt+ COB's. One of the reasons Citizen got themselves in the shit with LM80 was their data lacked real gravitas when talking about massive drive currents on these huge chips. The physics is not in their favour
Cheers
Mark
Randomblame
Well-Known Member
Yes, in this area you can work with graphite pads. I've lost 2 COB's to the shitty blue M3 pads(@37w!!!) so basically I do not like them.
Graphite pads seems to be better and an alternative below 100w but they are not as good as they are on paper.
I'm just as fast with thermal grease although it can be a mess sometimes. For strips or boards I realy like pads and tape but for COB's I would still recommend to use a thin layer thermal grease.
