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LED conversion of fluorescents
Yahoo Message Number: 135189
I just finished converting the two under-cabinet recessed fluorescent fixtures in the lounge area of our FL to LED's. I purchased a 5-meter length of warm-white LED 12V striplight from e-bay for $15.50, free shipping, and cut four strips from the roll. The strip is segmented in groups of 3 SMD5050 devices, with solderable contacts between. Each group of 3 devices is powered by 12V, and the segments are connected in parallel by the strip. Each strip I cut consisted of 8 segments, i.e. 24 LED chips. Carefully cutting through the middle of the solderable contacts allows the connection to be made at either end of the strip. I then soldered short wire pigtails to each strip.
 I removed the flexible light baffle from the fixture, cutting the grounding wire, then cut the red and white leads close to the electronic ballast. These I then wire-nutted to a pair of strips, then re-assembled the baffle into the fixture. Using the 3M adhesive backing on the strips, I then attached the strips to the baffle. For the fixture over the couch, I attached the strips directly above where the fluorescent tubes would have been - but to broaden the light dispersion horizontally, I installed the outside strip for the fixture over the dinette area on the angled part of the baffle to extend illumination further along the dinette table.
 The formal test results of the converted fixtures is that they now consume about 1.1 Amps each, compared to previously 2.2 A each, and the illuminated extent from each is a bit less than with the fluorescent tubes. The semi-transparent fixture lens effectively diffuses the light from the LEDs, such that the glare from the individual elements is suppressed. I noted that removing the lens improved the intensity within the normal dispersion angle of the devices, but replacing the lens increased the intensity over a broader area.
 Subjectively, the intensity of the more restricted area of illumination is similar to before, but the warmer light temperature makes it hard to judge. The result, as intended, is pleasantly adequate illumination where needed, with lower power consumption. For those who would like to do this conversion using a similar product, the 5 meter roll allows plenty of extra strips if the goal is MORE light than provided by the fluorescents where power consumption is not the concern. Total investment to convert the two fixtures was thus the $15.50 plus some scrap lengths of wire, solder, etc., with lots of additional strip left to play with.

Steve
2004 FL
2013 Honda Fit
Re: LED conversion of fluorescents
Reply #1 –
Yahoo Message Number: 135191
That's a really cost-effective conversion you did, Steve. Five meters for $15--wow! That's a LOT less than I paid.
 Coupla questions: 1) Can you give us a URL for the eBay listing? And 2) How far apart (longitudinally) are the LEDs?
 The LEDs on my strips are 3/8" apart, yielding 42 per strip, and I mounted three strips (126 LEDs total) in each light fixture, so that I'm getting somewhat more light than the original fluorescent lights delivered.
 It sounds as if your LEDs are more widely spaced on the strip (24 per strip instead of 42), and I gather that with two strips per fixture, you're getting somewhat less light than the original fluorescents--is that right? I'm just curious.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: LED conversion of fluorescents
Reply #2 –
Yahoo Message Number: 135197
Quote
That's a really cost-effective conversion you did, Steve. Five meters for $15--wow! That's a LOT less than I paid.
 Coupla questions: 1) Can you give us a URL for the eBay listing? And 2) How far apart (longitudinally) are the LEDs?
 The LEDs on my strips are 3/8" apart, yielding 42 per strip, and I mounted three strips (126 LEDs total) in each light fixture, so that I'm getting somewhat more light than the original fluorescent lights delivered.
Hi Andy,
 The seller is listed as 'top201088' in China. The 5m roll has 300 SMD5050 devices. Since this was from E-bay, I don't know of another url for him.
 The SMD5050 chips are about 5/8" apart, and about 3/16" on a side. Each strip fills the length of the baffle comfortably, and comprises 24 devices, so 48 LEDs per fixture. A more careful current measurement indicates about 0.95 Amps per fixture, or about 20 mA per device. Most strips I've seen with a higher chip density use the smaller SMD3528 devices - lower power, but allowing a higher chip density for a more uniform source.

Quote
It sounds as if your LEDs are more widely spaced on the strip (24 per strip instead of 42), and I gather that with two strips per fixture, you're getting somewhat less light than the original fluorescents--is that right? I'm just curious.
Well, to clarify, subjectively the intensity for a wide area below the fixture is comparable to the fluorescent, though I did not do a light meter measurement. Unlike the 'switched' mod for the kitchen fluorescent, I was not able to make an A/B comparison. However, the fluorescent fixtures will provide a lot of illumination at nearly 180 degrees off axis, which these modified fixtures will not. However, that is not needed in these under-cabinet locations, and the dispersion angle is sufficient to illuminate well the entire extended dinette table. I have no doubt that had I used more strips, I could have exceeded the on-axis intensity of the fluorescents. But, my goal was reduced resource consumption.

Steve
 p.s. Ordered on 11/6, with delivery range listed as 11/28 to 12/14. However, they arrived yesterday.
2004 FL
2013 Honda Fit
Re: LED conversion of fluorescents
Reply #3 –
Yahoo Message Number: 135205
Hi All,

I just did the same conversion, and can add some comments:
 On ebay, just search for "5050 strip led." There are many people selling them, and it is easy to find them for ~ $15 to $20 delivered. I bought two rolls from "eshopbuygo." Here is s link to the "pure white" ones: http://www.ebay.com/itm/160840993988?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 Interestingly, the two rolls were clearly from different manufacturers, so I assume this is a bit of a commodity item
Re: LED conversion of fluorescents
Reply #5 –
Yahoo Message Number: 135207
"Since this was from E-bay, I don't know of another url for him."
 If you go to any eBay listing, your web browser will show the listing's URL in its address bar. You can copy and paste that URL. E.g.,
 http://www.ebay.com/itm/NEW-5M-5050-SMD-LED-Strip-300-Leds-Warm-White-3200K-Waterproof-/120889512544?pt=US_Car_Lighting&hash=item1c25939260

Was this the item you bought?
 "The SMD5050 chips are about 5/8" apart, and about 3/16" on a side."
 OK, those are different chips than I have. Mine are about 3/32" on a side, hence one quarter the area of yours. So yours must have substantially greater light output per chip, hence fewer chips per running inch are needed to produce the same amount of light.
 It sounds as if you got enough light and greatly reduced power consumption, at a much lower cost than my conversion a few months ago. Ain't progress a wonderful thing? :-)

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: LED conversion of fluorescents
Reply #6 –
Yahoo Message Number: 135208
Hi Andy,
 The 5050 LEDs have three terminals per side (6 total), one pair per die. The 3528 LEDs have one terminal per side (2 total), one die. As far as I can tell, the 5050 LEDs are the same as three 3528 LEDs (light output and power consumption).

Cheers, Ken
 
Re: LED conversion of fluorescents
Reply #7 –
Yahoo Message Number: 135209
Thanks for that clarification, Ken. I did some research online, and learned that the numbers refer to the size of the LED die: 5050 LEDs are 5.0 mm x 5.0 mm, while 3528 LEDs are 3.5 mm x 2.8 mm. Generally speaking, 5050s are three times as bright.
 There are also other sizes, such as 3014, and of course the output form a strip depends upon not only the LED type but the spacing on the strip, so all these numbers are of relatively little significance. What counts is lumens per length of strip--generally specified in lumens per meter.
 Here's a page that does a pretty good job of explaining the various LED strip configurations:
 http://www.flexfireleds.com/pages/Comparison-between-3528-LEDs-and-5050-LEDs.html

...and here's a pretty good article on what to look for when choosing an LED strip:
 http://www.flexfireleds.com/led-strip-lights/top-4-considerations-before-buying-flexible-led-strip-lights/

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"