DIY LED Help

DonPetro

DonPetro

Well-Known Member
Positivity said:
@DonPetro...no, the only thing soldered are the small 670nm stars. Those are ideal cob holders holding the cxas down in all the pictures. They screw down and use push in terminals. You can remove the wire by inserting a small guage wire in the adjacent hole and pulling the wire out.

http://www.idealindustries.com/products/oem/led_holders/chiplok.jsp

Best thermal paste I know of is prolimatech pk3. Quite a few here use it including me. It's not a thermal adhesive though. So some have used kapton tape along with it to secure the led. Basically relying mostly on the vacuum created by the paste. I've never done it that way so I can't speak for longetivity...probably be good with the kapton though I'd think.

Screws aren't as bad as they sound...lol. Few tools and it only takes a minute..
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Hmmm...those are nice pieces of hardware. Not sure if they will work with the cob im planning to use. Is it best to use a holder or could i get by just fine without?
 
S

Skaumannen

Well-Known Member
You can go by just fine without the holders. SupraSPL uses thermal paste and kapton tape to hold the cobs in place. And some cobs come with screw holes so no holder is needed. But a holder can make it solderless. That was a big advantage for me, as i am not very good at soldering.
 
Positivity

Positivity

Well-Known Member
DonPetro said:
@Positivity
Ok...question: Can a driver have a higher current output than what a cob is rated for and if so by how much? For example if this COB(http://ca.mouser.com/Search/ProductDetail.aspx?qs=Qlzq7FOrON7bFzoKki4/bw==)has a forward current of 1800mA can i use this driver(http://m.ebay.ca/itm/191076829554?nav=WATCHING_ACTIVE) which is rated at 2100mA? Or would this unit be better: http://m.ebay.ca/itm/161320347325?nav=WATCHING_ACTIVE
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The mouser links not working. What cob is it? Cree?

If your driver has a higher current than what the cob is rated for it will most likely overheat quickly and meltdown. It may be possible to do that but it would take extreme cooling. They work well when they are efficient anyways. 50%...1.4a out of a max 2.8a cxa 3070 is what most do. I've been at 1a and lower to get even more light and less heat per watt.

What cob? Just gotta match it to a driver..meanwell..meanwell...meanwell...lol.
 
DonPetro

DonPetro

Well-Known Member
Positivity said:
The mouser links not working. What cob is it? Cree?

If your driver has a higher current than what the cob is rated for it will most likely overheat quickly and meltdown. It may be possible to do that but it would take extreme cooling. They work well when they are efficient anyways. 50%...1.4a out of a max 2.8a cxa 3070 is what most do. I've been at 1a and lower to get even more light and less heat per watt.

What cob? Just gotta match it to a driver..meanwell..meanwell...meanwell...lol.
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Its a Luminus Devices cxm2730
http://ca.mouser.com/ProductDetail/Luminus-Devices/CXM-27-30-80-36-AA00-F2-3/?qs=sGAEpiMZZMu4Prknbu83y1zhPTc0SxQxaRM46v/p8vCzu7Lcfc2cuQ==
 
Positivity

Positivity

Well-Known Member
@DonPetro
Looks like it's about equivalent to a z4 bin cree 3070?

I'd still take a cree z4 though just on what I've seen. Luminus could be just as good though I'd guess.

Guod linked this earlier. Not sure how much shipping would be.
http://www.leds.de/en/High-Power-LEDs/Cree-High-Power-LEDs/Cree-CXA3070-warmwhite.html

1.8a constant current meanwell driver with at least 36v and 75w available

Not as familiar with meanwell drivers as some unfortunately. Been using inventronics drivers...although I'll be switching to meanwells if I build another light. They are a more affordable option. Meanwell you need to get the right letter designation for dimming options.

I'll take a look...but someone should beat me to it hopefully
 
DonPetro

DonPetro

Well-Known Member
Does the power factor rating on a driver relate to its efficiency? For example would a driver with a power factor of .95 be more efficient than one rated at .6? How important is the wattage of a driver?
 
Positivity

Positivity

Well-Known Member
Power Factor (abbreviated PF) is the ratio of real power to apparent power in an AC power system and is expressed as a number between 0 and 1. Real power is the actual power drawn by the load whereas apparent power is the product of the load current and load voltage. Since the voltage and current may be out of phase this product may be significantly greater than the real power.

PFC is the abbreviation for Power Factor Correction. In order to maintain a high power factor, switch mode power supplies (including LED drivers) must employ some form of power factor correction.

This is an important issue because a load with a low power factor draws more current than a load with a high power factor for the same amount of real power transferred. Low power factor therefore results in greater power losses in the utility lines. There are a number of standards now in effect requiring certain levels of power factor correction in switchmode power supplies and/or LED drivers.


More info on drivers, pertains to meanwell, etc. also...

http://www.inventronics-co.com/jszc.aspx?c_kind=3&c_kind2=18
 
Positivity

Positivity

Well-Known Member
I do wonder how much actual power it'd draw...ya know...a 200w pf corrected vs 200w not....both running the same leds..

What I worry most is that they took the time to do it..among other things like safety certs, warranty, reputation...

You asked importance of wattage of driver...not sure exactly what your asking..

But...in my limited experience..

You want to give 10% to 15% extra for driver inefficiencys. My drivers are 90% efficient and up...I give 10% sometimes even a bit less dependant on the setup of leds. The driver does run warmer when running at full capacity. On my light the drivers get cooled by fans and are potted so they don't heat up much. If the drivers had no circulation they would probably have a shorter lifespan running at maximum.

Giving 15% extra is definitely optimal. Having too much extra isn't always a good thing either as efficiency decreases under light loads. The datasheets of drivers usually show that stuff. So you want to have your leds and drivers well thought out and matched if possible. 15% extra watts on a 90% efficient driver will help it to run optimal and cooler
 
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DonPetro

DonPetro

Well-Known Member
Positivity said:
I do wonder how much actual power it'd draw...ya know...a 200w pf corrected vs 200w not....both running the same leds..

What I worry most is that they took the time to do it..among other things like safety certs, warranty, reputation...

You asked importance of wattage of driver...not sure exactly what your asking..

But...in my limited experience..

You want to give 10% to 15% extra for driver inefficiencys. My drivers are 90% efficient and up...I give 10% sometimes even a bit less dependant on the setup of leds. The driver does run warmer when running at full capacity. On my light the drivers get cooled by fans and are potted so they don't heat up much. If the drivers had no circulation they would probably have a shorter lifespan running at maximum.

Giving 15% extra is definitely optimal. Having too much extra isn't always a good thing either as efficiency decreases under light loads. The datasheets of drivers usually show that stuff. So you want to have your leds and drivers well thought out and matched if possible. 15% extra watts on a 90% efficient driver will help it to run optimal and cooler
Click to expand...
I think you pretty much answered my question and i think i have a decent grasp of what i need. Im just having a hard time matching the numbers.
 
Positivity

Positivity

Well-Known Member
DonPetro said:
Thought i had a found a driver but then noticed 79% efficiency. Yikes!
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1.8a is a little hard to find in meanwell. This driver page has the options broken down in watts.

http://www.trcelectronics.com/Meanwell/power-supply-led-constant-current.shtml

The luminus you want to run is 36v at 1.8a dissipating about 65w. According to the datasheet the max current is 2.7a and 37v dissipating 100w.

The 1.4a drivers linked above will be by far the best bang for your buck. $15 for a driver is awesome.

1.4a x 35v = 50w

Really think you should consider 1.4a. It will be more efficient...easier to cool....less light in one spot...

1.95a 80w driver would work. Adjustable internal pot between 1.17 and 1.95a. 1.95a x 35v = 70w. 10w to spare..
http://www.trcelectronics.com/View/Mean-Well/HLN-80H-42A.shtml

1.95a 80w driver. External dimming. 70w per led.
http://www.trcelectronics.com/View/Mean-Well/HLG-80H-42B.shtml

2.2a 100w driver. External dimming. 80w per led.
http://www.trcelectronics.com/View/Mean-Well/HLG-100H-42B.shtml

2.5a 120w driver. External dimming. 90w per led.
http://www.trcelectronics.com/View/Mean-Well/HLG-120H-48B.shtml

And many many more options....other companies..etc..larger drivers to run multiple cobs..

Be sure to try supras page for driver recommendations....

https://www.rollitup.org/t/diy-leds-how-to-power-them.801554/
 
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Positivity

Positivity

Well-Known Member
DonPetro said:
Hmmm...those are nice pieces of hardware. Not sure if they will work with the cob im planning to use. Is it best to use a holder or could i get by just fine without?
Click to expand...

Looking at the datasheet for the luminus...

They have holes drilled out in the base for screws. simply use a good TIM like arctic silver or prolimatec pk3...not a permanent epoxy....and screw down with self drilling screws. Predrill a hole for the screw would be a good idea.
 
guod

guod

Well-Known Member
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