Author Topic: DIY LED bulb (Read 25071 times)

Rover · « **on:** December 30, 2010, 05:38:05 PM »

Hi all,

The whole point of this is to use some of my battery bank energy that normally (for me ) goes unused in the winter. I decide to start using some of it for landscape lighting, in this case a pole light in front of the house. I've tried commercial (eBay) LED lamps, HF 5W CFLs , but the last was a corn/tower style SMD LED light bulb off of eBay (5W SMD 36 LEDs). It did OK job, but I wanted brighter. I couldn't find anything (OK there are probably some CFL's but I was stuck on LEDs for some reason), with more than 36 LEDs that I could use in my configuration (12V, and I wanted to keep using an E27 base).

The problem is the idea stuck in my head and I could not get rid of it, so I guess I had to, just to do it.

The final result was this... on the left is my bulb, on the right the 36 LED commercial unit. Mine has 56 SMD LEDs (5050 , 6000K), draws ~ 14 W.

I started with some rigid led strips, 60/meter in 2 1/2 meter strips. I'm using a 2" diameter PVC pipe as the form , and the E27 base off of a burned out 30W 110V CFL

This is the assembly, strip cut into 4 LED lengths and crazy glued to the pipe. I had soldered wires to each strip )kinda looks like a very small ECM rewire

)

Finally powered up. In a subjective comparison to the 36 LED bulb purchased , this one was substantially brighter, more than expected. Also note that I had planned on 60 LEDs but ran into a cutting issue on the strips and had to drop 4 LEDs

I have the bulb mounted outside now, unfortunately this are not considered weatherproof and I should probably coat the bulb with something, I'm thinking either clear casting epoxy or just spraying with urethane.. any thoughts?

DamonHD · « **Reply #1 on:** December 30, 2010, 05:40:49 PM »

Nicely done...

Rgds

Damon

Bruce S · « **Reply #2 on:** December 30, 2010, 05:46:39 PM »

Rover, that's some light you got there

Any chance one of the old covers for the HF cfl's would fit over it?
Are my eyes going south or does the pic make the light set look square, versus the build being round

Nice Job!!
Bruce S

Rover · « **Reply #3 on:** December 30, 2010, 05:53:02 PM »

It's a photographic effect no idea why it looks square, its not. It is too wide/tall for an HF CFL cover. The light is in an enclosure outside, I just need some minimu moisture protection.

I just took a shot of it on top of the pole , (no flash used, this is all ambient, and post light)

ghurd · « **Reply #4 on:** December 30, 2010, 05:55:43 PM »

There sure do get to be a lot of wires in there!

The math does not sound right in my head. How are they wired together?
G-

Rover · « **Reply #5 on:** December 30, 2010, 06:11:54 PM »

Hey Ghurd,
I used commercial strips, so I didn't have lot of leeway with the wiring ( I also did not want to solder ~ 60 SMDs, my eyes can't do that). On the strips as received, each 5050 led (3 chip) is mounted parallel with each having a SMD resistor (mark 151) , so 150 ohm.

The striips are cuttable into 1 led lengths so any number can be used in a smaller strip, makes sense since each has its own resistor.

in my case I cut 14 strips, each with 4 LEDs , (I meant to do 15 but messed up on the terminal ends of the strips) for 56. I then connected each strip parallel to the source voltage.

Falls in line with the manufaturer's specs with the strips , wattage was measured using my "Wats Up" at ~ 12.5 V from my little U-3 test battery

dnix71 · « **Reply #6 on:** December 30, 2010, 06:28:38 PM »

Nice work. These run off half wave 120v then I guess. What the expected life? I snowy weather you shouldn't need a fan to cool them, but under a globe in the summer it might hot enough to matter.

Rover · « **Reply #7 on:** December 30, 2010, 06:30:52 PM »

Nope these are 12V DC. I use E27 bases since I can get nice fixtures for regular 110V, and if needed just change the source to puit them on 110V ( like if I'm going to sell the house etc, not happening though

)

Madscientist267 · « **Reply #8 on:** December 30, 2010, 07:43:40 PM »

Quote

Are my eyes going south or does the pic make the light set look square, versus the build being round

It's an optical illusion caused by the close proximity of one "miller light" beer can in close proximity to the lamp...

Nice job dude. Covered everything but the cost... what did it run you to build it (including beer

)

Steve

Rover · « **Reply #9 on:** December 30, 2010, 08:14:04 PM »

Ok this ran ~ 40$ though I have sincve sourced parts for less (my eagerness to do this outweighed my thrift side). should be able to do it for less than half that.

(ssshhhh on the beer can, I may use that as a template next time)

ruddycrazy · « **Reply #10 on:** December 30, 2010, 09:55:31 PM »

G'day Rover,
Looks good mate, now since you mentioned about that can and I won't say *eer as I have heard that yankie *eer isn't fit to give it your dog... OK now thats out of way, how about a clear beer bottle for a waterproof housing. Just put a blob of epoxy putty on the end of each led string then feed each one in until it hits the bottom. Arrange how many strings you need then when each of the strings are cured at the bottom of the bottle use some more epoxy putty to secure the tops of each string. Assuming you cover the inner diameter of the bottle then all the wiring can be placed in the centre and epoxy a E27 base on to suit as you did before. In the day it will be a great talking piece and it would be interesting to see the light output as the glass should merge each led together.

Just a thought...

Cheers Bryan

Madscientist267 · « **Reply #11 on:** December 30, 2010, 11:20:42 PM »

Quote

(ssshhhh on the beer can, I may use that as a template next time)

Hahaha I hear ya... May I suggest Mike's Harder Fruit Punch? LOL

The best of us use a little calmer to stop the soldering iron jitters.. hahah Looks like you needed it during this run..

Steve

Simen · « **Reply #12 on:** December 31, 2010, 01:45:02 AM »

Nicely done!

I did just the opposite a while ago; i had a bulb a bit like your commercial one, and streched the bits into a led-strip.

I got 4 of these:

The specs are 12V, 8.1W, 2900K, 665lm, 56-leds. They are a bit pricey ($60.-), but beats both a 60W ind.-bulb and 11W CFL...

Rover · « **Reply #13 on:** December 31, 2010, 08:08:58 AM »

Ruddycrazy,

"how about a clear beer bottle for a waterproof housing", I'm pretty sure the thickness of bottle glass would cut down too much on the light output. I have the bulb in a fixture which has a housing, so not so worried about that. I'm just trying to come up with a light coating for the assembly to make it more water resistant. The LEDs are mounted on a PCB board with no protection.

I'll probably just go with some spray urethane.

zap · « **Reply #14 on:** December 31, 2010, 10:50:25 AM »

Quote from: Rover on December 30, 2010, 08:14:04 PM

Ok this ran ~ 40$ though I have sincve sourced parts for less (my eagerness to do this outweighed my thrift side). should be able to do it for less than half that.

Care to mention where you sourced the parts for less?

Rover · « **Reply #15 on:** December 31, 2010, 10:54:31 AM »

Zap,

Got em on Fleabay, they are all over the place , do search 5050 SMD LED strip.

This is 5 meter 60/meter, cuttable every 3.

Think it was 80$ for the 5 meters, and included a 6A 12 VDC supply

zap · « **Reply #16 on:** December 31, 2010, 11:23:24 AM »

Thank you sir

I'll have a look.

dnix71 · « **Reply #17 on:** December 31, 2010, 05:48:03 PM »

Zap, here's 5000 loose pieces for about $800.

That's a lot of soldering. The FAA might not appreciate a light that bright though.

http://cgi.ebay.com/5000-pcs-PLCC-6-5050-SMD-3-CHIPS-white-10000mcd-LED-/120588612820?pt=LH_DefaultDomain_0&hash=item1c13a434d4

This one has 300 on a strip that can be cut every 3 LEDs Ten 5 meter strips for just over $600.

http://cgi.ebay.com/10X5M-Warm-White-SMD-5050-Waterproof-300-LED-Strip-Lamp-/350352760366?pt=LH_DefaultDomain_0&hash=item5192a6de2e

Rover · « **Reply #18 on:** December 31, 2010, 07:51:51 PM »

Ok, before we all get carried away.

I like the strips , density of at leat 60/ meter , primariliy for the ability to do a quick assembly and have a decnet light output.

But there are some downsides, some I can live with. Most importantly before rushing out and buying them, is that they are self contained with current limiting resistors. You might say, jeeze thats great, but actually , it is limiting , pardon the pun. If you you would like to drive them with some of Commanda's most generous and a highly educating LED driver circuits , you pretty much can't with these strips. The penalty for the current strips is more dissipated energy over the number of LEDs , and a caution about uncontrolled voltages from a battery bank etc. I will regulate my voltage... in this case yes, voltage, not current since the strips already have resistors.

There is a trade off for simplicity in design and numbers and manufacturing , the strips are easier to work with, however you could make a much more efficiient system from scratch using the proper current driver. ( I just don't want to solder that many SMDs, you could of course go wth high output Crees, but then you have very bright points of light)

I can live with the trade off, for now, I'm actually surprised Commanda hasn't chimed in on this..

commanda · « **Reply #19 on:** December 31, 2010, 08:45:33 PM »

Chiming in as requested.

I did read most of the start of this thread. The first thing that struck me, was the inherent inefficiency in power lost in the built-in resistors.
Like many things, there is a trade-off between ease & convenience, versus the long term cost. And the problem of connecting to a variable voltage battery source.

I won't mention the sheer wrong-ness of using an E27 socket, which is reserved for mains powered bulbs.

Amanda

zap · « **Reply #20 on:** December 31, 2010, 11:37:37 PM »

Quote from: dnix71 on December 31, 2010, 05:48:03 PM

Zap, here's 5000 loose pieces for about $800.

Hehe... way more than I need. Those strips are pretty neat though. I was searching for strips for a day time running light for a bicycle after seeing a nice "chasing led light" youtube clip. I found this impressive clip while I was searching. http://www.youtube.com/watch?v=sf_vmdjmFNk
I love the "inch worm" effect!

Rover · « **Reply #21 on:** January 01, 2011, 12:45:35 AM »

Quote from: commanda on December 31, 2010, 08:45:33 PM

Chiming in as requested.

I did read most of the start of this thread. The first thing that struck me, was the inherent inefficiency in power lost in the built-in resistors.
Like many things, there is a trade-off between ease & convenience, versus the long term cost. And the problem of connecting to a variable voltage battery source.

I won't mention the sheer wrong-ness of using an E27 socket, which is reserved for mains powered bulbs.

Amanda

Thanks for chiming in Amanda!

I agree as posted...(yet I will probably repeat this build ). As far as the E27 base , yeah I know it may look confusing , but the fact is here, and on my boat , the light sockets for 12V are E27 (from factory). OK I have an older boat and stuff has surely changed to make sense. No excuse for my build , the only reason was to use an existing fixture, that if needed could be reverted back to AC . I do label them prominently 12V DC when I do this.

I do have a question though, if I , or others, where to continue using this type of strip, one of the things I see that is needed, ( also smacked into me by some on IRC .. DanG, others)
is some form of protection circuit.

any thoughts appreciated.

commanda · « **Reply #22 on:** January 01, 2011, 02:14:35 AM »

If you're in a closed environment (on a boat, obviously. Did I miss this somewhere?) then using inappropriate connectors is less sinful. Especially if it is clearly labelled. I'll let you off this time.

As for protection, I see the greatest need being environmental.

Electrical ? Series fuse, parallel reverse biased diode, parallel MOV or zener to clamp transients.

Amanda

ghurd · « **Reply #23 on:** January 01, 2011, 11:36:37 AM »

Rover,
I can not find good data on the LED itself.

Can you check the voltage on the built in resistor?
If it is ~3.5V then its maybe not so terrible.
I have a feeling it may be ~9.5V, and that would be very bad in the efficiency department.

The E27 and 12VDC is not a serious crime, IMHO.
Can buy factory made 12 and 24VDC LED bulbs and CFLs with E27.
Buying a DC bulb with a lot of light output almost always comes with an E27 base.
G-

Rover · « **Reply #24 on:** January 01, 2011, 12:23:04 PM »

Hi GHurd ,

here is he spec on the LED itself

http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fspecs%2F5050smdpw_specs.htm

the current limiting resistor is 150 ohm per led

DamonHD · « **Reply #25 on:** January 01, 2011, 12:40:05 PM »

I think the ES base is a crime generally. It's used in the UK for spotlights for example. I have so many poor connections compared to the rather more binary bayonet connection that's more common for similar-size bulbs, or even the GU10 fitting!

Rgds

Damon

Opera House · « **Reply #26 on:** January 01, 2011, 12:49:04 PM »

Found a super deal at SAM'S on a two pack of 4W 120V GU10 145 lumens LED. Lights Of America, sure they are quickly replacing LUCAS as the prince of darkness but still a deal at $4.71 for a pack of two. Rated at 35ma, I measured 21ma (12V) on the 560 ohm dropping resistor and 95V DC forward voltage on the LED assembly.

Assembly easily screws apart so a different mount could be made. Just a bridge rectifier and a 560 ohm current limiting resistor. Shown with shrink tubing and lens removed. There is also a 47,000 ohm bleed resistor across the LED. I can only imagine this is to eliminate capacitive effects so the bridge rectifier can be a lower rated voltage. Would have liked the forward voltage to be lower but I still bought all they had in stock. I assume these were marked down from the usual $14 because no one buys GU10 bulbs and thy seem to be going with GE now for LED. Your store may have the same deal. I might make a grow light and unscrew the LED and just mount it to some aluminum. Then I could use the heatsink and lens with a 3W LED for my camp which is only 12V.

Rover · « **Reply #27 on:** January 01, 2011, 04:21:27 PM »

Hmmm, I onlly have a Costco membership, doubtful they will have them, how many you buy?

Opera House · « **Reply #28 on:** January 02, 2011, 12:20:46 PM »

Bought the last six at that store. On closer inspection, the 47K resistor is on the input side of the bridge rectifier. This is likely to eliminate parasitic capacitance that can cause the LED to glow when the switch is open. Even with this resistor installed this LED makes a nice night light with a .047uF capacitor in series with the power. Wouldn't light with .022uF because of the 47K resistor. At normal voltage this resistor consumes 1/3 watt. With that resistor removed a .02uf is more than enough for a night light. It even still works with only a 150pF. Makes it easy to see the 6 by 6 LED array. The SMT resistor easily snaps with a pair of wire cutters.

Madscientist267 · « **Reply #29 on:** January 02, 2011, 08:40:55 PM »

Thats my favorite part about SMT - REALLY easy to get rid of... now if we could just somehow convince the ...

Oh who are we kidding...

Steve

OperaHouse · « **Reply #30 on:** January 04, 2011, 04:26:08 PM »

Went back to SAM'S today and they came up with another 4 packs. This time they dropped the price to $3.01 a pair. Needless to say I bought them all.

Rover · « **Reply #31 on:** January 04, 2011, 05:21:02 PM »

OperaHouse ,
Cool , Have fun with them I'm hoping my 300 leds come this week, first thing if they do, is to hook the entire string up, should pull ~ 6 amps, be interested to see how bright that will be.

Bruce S · « **Reply #32 on:** January 05, 2011, 09:00:14 AM »

Quote from: Rover on January 04, 2011, 05:21:02 PM

OperaHouse ,
Cool , Have fun with them I'm hoping my 300 leds come this week, first thing if they do, is to hook the entire string up, should pull ~ 6 amps, be interested to see how bright that will be.

Rover;
I noticed that they are right here in St. Louis, well actually in an area called Earth City

.
I thought maybe , just maybe they would have discounted strips or products and would try to score a few. Nothing doing

Only thing I would save on is shipping.
Lots of really cool stuff out there though, like being a kid in a candy store again

WOW is there some STUFF out there, might become my new favorite candy store.

Our company has a bulb recycling collection point. There's always spent CFL bulbs in them with standard bases.
Cheers
Bruce S

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Author Topic: DIY LED bulb (Read 25071 times)