# Led lights



## dlane (Dec 5, 2017)

Any one put these to use, I ordered 10 50w cool white , will be using some of them around the shop http://www.ebay.com/itm/110v-220v-LED-Floodlight-20W-30W-50W-Cool-White-COB-Chip-Smart-IC-Driver-Lamp/272611210818?_trkparms=aid%3D555017%26algo%3DPL.CASSINI%26ao%3D1%26asc%3D41376%26meid%3D65c07a47dd6843129bcd7f244297edb5%26pid%3D100507%26rk%3D1%26rkt%3D1%26&_trksid=p2045573.c100507.m3226
Hope the link worked was acting funny.


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## Eddyde (Dec 5, 2017)

Haven't used those in particular but have messed around with some similar LED chips I bought surplus. One thing to keep in mind, you need to mount them to some sort of a heat sink, while they don't generate a lot of waste heat, they are sensitive to it.


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## RJSakowski (Dec 5, 2017)

This has got to be the lowest cost in terms of $/lumen.  I ordered a bunch for myself  

dlane, I got a chuckle out of your signature line.  Are you concerned?


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## dlane (Dec 5, 2017)

RJ , a little concerned but I won't be out much if they go puufff, I think the cords , plugs, and some sort of heat sink will be the costly part. Have any good ideas for heat sinks, good cheap ones .


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## RJSakowski (Dec 5, 2017)

Same here.  Two glasses of beer at a restaurant I was at last week were more than 10 of those LED's.  I will most likely dip into a supply of heat sinks that I have.  I am thinking about pulling the guts about of some of the burnt out CFL lights and mounting the heat sink and COB light to it for a screw-in light.    My woodworking shop has some inaccessible incandescent lighting in the rafters and replacing them with longer lasting and higher output LED's will be a plus.


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## dlane (Dec 5, 2017)

From what I hear I need to put some kind of pukey between the light and the heatsink that transfers heat any idea what would work for that ?   I may have to change my signature


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## Dave Paine (Dec 5, 2017)

Do a search for either thermal grease or heat sink compound.   Available in electronic stores which sell computer parts.   Commonly used between the CPU and heat sink/cooler.


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## dlane (Dec 5, 2017)

After rereading the listing they have an aluminum back that gets rid of the heat


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## RJSakowski (Dec 5, 2017)

The aluminum substrate by itself would probably not be sufficient. to adequately cool the assembly. Typically, the substrate is mounted to a larger heatsink.  For the 50 watt unit, somewhere around 30 watts of heat will be generated.  This is comparable to a pencil style soldering iron. Heat sinks are normally rated in terms of the temperature differential between the heat source and the ambient surroundings divided by the heat dissipated (ºC/watt) a parameter largely determined by surface area. 

 It is important to keep the temperature of the LED's from rising too high as a higher temperature causes reduced output, reduced efficiency, and shorter life span.  Somewhere around 60ºC is a good target.  With a 20ºC ambient temperature, the temperature difference wi be around 40ºC.  There will be a temperature drop between the LED and the substrate and between the substrate and the heat sink and finally between the heat sink and the surrounding air.  The aluminum substrate helps to tranfer heat from the LED to the heatsink resulting in a lower temperature differential.


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## dlane (Jan 2, 2018)

Yup they get hot quick without a heat sink and they are proud of those, but they are bright


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## texanjohn (Jan 2, 2018)

Any Auto parts store can sell you a tube of “ Dielectric silicon lube” that’s what GM uses between ignition modules and distributor bases, cheap, easy to applie and it works .


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## whitmore (Jan 3, 2018)

dlane said:


> Any one put these to use, I ordered 10 50w cool white....


It'll flicker, of course (might give odd visual effects on moving machinery).   It also
means you need a good enclosure to keep the 120VAC from fingers.   Buying
an enclosed lamp would be thriftier.   Is the 'heatspreader' plate electrically
live?  If electrically  insulated, how reliable is that insulation?

I don't like these designs; a power surge will take 'em out, and because there's
dozens of LEDs in series,  one that fails open will darken the whole string.


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## aliva (Jan 3, 2018)

heres one source for heat sinks
https://www.banggood.com/search/heat-sink-aluminum.html


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