LED Christmas lights

[Soapman]

I just bought some of those LED christmas lights and came up with a question. It's a strand of 100 multi colour. There is a tag on it that says 120v,60hz,0.04a,4w. My question is, Is each light 4w or is the whole stand? 4watts for the whole strand sounds too good to be true, yet 4watts each is still 400 watts for this one strand. I asked the guy at canadian tire and I'm not sure he even knows what a watt is. I did a quick search and came up empty. Any ideas?

[Norm]

  Thats easy.....V x A = W

0.04a x120v = 4.80

             ( :>) Norm.

[zap]

Most likely it's 4 watts for the entire string.  A 4 watt LED would be blindingly bright and 100 would light a good sized room.  Consider a whole string of 100 small tree bulbs is about 45 watts in slow "chase" mode and about 85 watts with every bulb burning.

[altosack]

Most LEDs like this can't handle more than about 20 mA at 2V or so, which is  40mW, times 100 is, hey !, 4000mW or 4W.

Multi-color LEDs are low voltage, and must be put in series to get up to a higher voltage. Since LEDs are about 20 mA, and your specs say 40 mA (0.04A), there are probably 50 in (2) series strings, each of which would then have 2.4V, which sounds about right. Since LEDs are diodes, if you have 2 strings, you have a rectifier if they are attached out of phase.

Just in case that sounded like greek, yes, 4W is for the whole string.

Dave

[terry5732]

When someone parallels a bunch of these strings to make their main rectifiers I wanna see pics.

[JW]

Hear that all you who have tried to make led-solar PANELS.. yOU can re-use your grid panels to make a rectifier bridge for a single phase using 4.5vdc, as the operarating voltage for 4.5dc system(providing there clear lens blue leds).  If you had 1000 leds you could series parallel them for one phase, I guess .... 500 for the anode lead and 500 for the cathode for DC output, then feed AC into the junction.

Just having E-fun

JW

[kenputer]

I plugged a string of 70 LED's in to my wattmeter and it only read .01 watts being drawn.

Ken

[AscenXion]

I am going to be building a large home in about a year. And I was interested in using led lights as my "main" lighting. Not lighting to be able to do any tasks by, just ambient light to be able to find my way in the dark of night. I know that for actual light output vs energy input, cf bulbs are more efficient. I REALLY like the idea of using led's however, and I was wondering if anyone on here had any experience with this.

My plan is to use light strings or some such thing and place as few leds into the ceiling as possible, just enough to provide adequate lighting to see by.

[ghurd]

Don't use too many LEDs in a series string, don't use AC, keep the amps well below the data sheet max, use the widest angle LED you can find, make the LEDs replaceable, don't use "internet LED math" as a substitute for a meter...

And don't use Chinese LEDs.

G-

[Bruce S]

Soapman

Here's a link to a guy who uses a set for lighting in his RV.

http://altenergy.blog-city.com/led_apps.htm

 He has a lot of information about what he's done, of course they have the parts and such, but it does seem to do what I beleive you're looking for.

The price doesn't seem too outlandish either..

Cheers

Bruce S

[Soapman]

You guys answered all my questions and then some. Thanks for all the help. My wife loves Christmas lights but we started popping breakers all the time. Way to many lights! We just moved to a new house and I told her I would put up as many lights as she wanted. But they have to be LEDs. So we bought the first strand of 100 and she loves them. After all of you confirming how energy efficient they  are, She went and bought more. Alot more. So I spent a whole weekend putting up LED lights. I now have 1605 multi-coloured light on my house just waiting for me to turn them on. ( it's not quite close enough to Christmas yet) Would you believe she wants more?! Now you see why we were popping breakers with the normal lights.

[alancorey]

Finally, something I've got actual experience with.  I've bought from http://www.superbrightleds.com and been fairly happy, but I've only had them a few months and don't run them often.  I've seen some people posting that the cheaper ones get darker with age or overcurrent, but I haven't seen that yet.

I've got a small 8'x12' shed on some land that I probably won't pay to get the grid run into, and I've bought some LEDs I use for light in there, powered by a 7.2 AH battery I bring home to charge every couple of months.

Superbright LEDs sells a little circuit board for about $3 that holds 9 LEDs and 3 series resistors.  I've got 4 of these boards hung from the ceiling and it is possible to read in there, but I find I want a little more light if I'm going to do fine work for some period of time.  I'm 52 and don't see as well as I used to.  These are 8000 MCD LEDs with a 45 degree viewing angle.  There are a total of 36 of them, consuming about 2.75 watts total.  I'm using 150 ohm series resistors for each string of 3, calculated for 20 ma at 13.8 volts, and later checked with a meter.  Since I don't have anything onsite to charge the battery with yet, the voltage is more often down around 12 volts.

This is a closeup, sort of, of one board.  Because the LEDs have a half-power beamwidth of 45 degrees I tried to aim them to cover everywhere in a downward-facing hemisphere.  The ones on each end point 45 degrees off to the ends, and all but the center one point 45 degrees off to the sides.  No matter where you look at it from, there's always one that seems brighter than the rest.  







Here's my shed full of junk, lit only by the LEDs.  The camera makes it look bright, but this is a 4 second exposure.

I won't claim these are cheap, and probably don't begin to compare to LED Christmas lights that way.  This is about $60 worth of LEDs and boards, but the prices have come down a little since I bought these.  I would definately consider them more than bright enough to get around by, and plan to put switches in for each board.  I have a white/clear fiberglass roof on the building (no windows) and there's enough reflected glow from even one board running to see the roof from 100 feet away.

  Alan