Going even more off topic - these aren't particularly useful shop lights, but they are blindingly bright and incredibly cheap. 100 Watts, 9000 lumens. They need heat sinking (I've used CPU fan/sink combos).
http://www.ebay.com/itm/380515680644 On Sat, Nov 8, 2014, at 05:06 PM, Tom Easterday wrote: > Since this thread is heading down the path of DIY, and since I just ordered > some more of these for a lamp I am upgrading, I thought I would mention this > very useful LED module from Seoul Semiconductor which is powered directly off > 120/220V mains. All that is required is a heat sink to mount it to and Bob’s > Your Uncle. > http://www.seoulsemicon.com/en/html/application/application.asp?catecode=3011&subcode=28 > > <http://www.seoulsemicon.com/en/html/application/application.asp?catecode=3011&subcode=28> > This very bright one is going into my lamp: > http://www.seoulsemicon.com/_upload/Goods_Spec/SMJE-XV12W2P4(0).pdf > <http://www.seoulsemicon.com/_upload/Goods_Spec/SMJE-XV12W2P4(0).pdf> > They can be found at Digi-key, Mouser and various other places. > -Tom > > > On Nov 8, 2014, at 4:33 PM, Jon Elson <el...@pico-systems.com> wrote: > > > > On 11/08/2014 11:29 AM, Dave Cole wrote: > >>>> I wonder how long it takes to pay back the $75 > >> difference at 9 watts? > >> > >> 9 watts x 2000 hrs per year = 18KWHR/yr @ $0.10 per KWHR that would > >> be $1.80 per year so a payback of $75/$1.8 = $41.6 years > >> > >> > > I made up my own LED retrofits, because I couldn't find > > anything that looked > > like it would work well. I bought Cree 1W LEDs, and put a > > string of 20 of > > them on strips of PC board material with little grooves > > cutting the > > copper path. Each LED has 2 square inches of copper as a > > heat sink. > > I used commercial LED lighting regulators, which were pretty > > expensive. > > I have these in the kitchen, where they are on a LOT of the day. > > One strip of 20 LEDs is brighter than 2 32 W 48" fluorescents. > > Not only looks brighter, but my photometer also says they are > > brighter. I have them suspended inside the drop ceiling dual > > fluorescent fixtures with 2 x 4' plastic diffusers that were > > there before. > > > > I measured the power draw of the old magnetic ballast, it > > was 103 W > > with a real power meter. The new system reads 21 W. > > > > I guesstimate payback in about 3 years. > > > > I first did a 10 W unit with a power supply I made myself, > > it has been running > > about 18 months so far, and is still working really well, > > too. I think if you > > use good LEDs at reasonable current levels, the dimming over > > time will > > be very slow. Cree has lifetime charts that show several > > hundred K hours > > before significant loss of brightness. I did make sure the > > LEDs run pretty > > cool, much cooler than a lot of the stuff sold in stores. > > > > Jon > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
