Instructables

How to make cheap but very powerful LED bulbs

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Picture of How to make cheap but very powerful LED bulbs
It's been almost a year since I started to "LEDify" my home, with results more or less encouraging, but only an accident made ​​me find the best solution so far.

 
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Step 1: Motivation

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How often happened that you or someone in your family, by mistake, to overthrow the desk lamp? If you are like me, this has happened many times...  For this reason, the last time my offspring slammed my desk lamp one more time, with an innocent "UUPS!", I exclaimed Enough!

Warning! CFL bulbs contains a small quantity of mercury and this is a very toxic substance.
If by accident or intentional, you have broken an CFL bulb, it is advised to ventilate the room as good as possible, in order to dissipate the toxic vapours.


I decided that I have to replace the CFL bulb from the desk lamp, with something more shock resistant...

But that could withstand the treatment of a 10 years child and at the same time to make enough light to work at desk in good condition, to be reliable in operation and decently priced? If only a few years ago, there was no a solution to this question, the answer is now clear: a power LED.

Step 2: Materials

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As I already had some Cree MX6 Q5 LEDs with 3W power and maximum light output of 278 lumens used in some older projects, I decided to use them for this project too. The LED will be placed on a 5cm x 5cm heat sink recovered from the chipset of an old computer motherboard.

For simplicity, I decided to use a switching power supply of a mobile phone, perhaps together with an electronic adapter that would give me the necessary voltage and current to power the LED. For this purpose I have chosen the power supply of a defective mobile phone Siemens A52 having, according to the manufacturer, an output voltage of 5V and a current of 420mA.

An socket from am old CFL bulb should protect all the electronics.
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MooMeat4224 days ago
personally I find the color of the Q5 LED to be much too green without much blue to even it out. But then again I have blue CFLs for the main source of light in my room
nice bulbs.
zubain1 month ago

Its an awesome idea to use the cell phone chargers to directly power the LEDs without using wasteful resistors. Can you please advise the best configuration using 1 W LEDs. Do you think that I can directly connect 2 x 1 W LEDs in parallel to a cell phone charger?

tudurache (author)  zubain1 month ago

1W LEDs requires about 300mA but phone chargers generates usually more than 700mA... so connecting 3 or better 4 * 1W LEDs in parallel should work, but in order to equalize the LEDs characteristics it's recommended to connect in series with each LED a small value resistor... about 0.5 Ohm or 1 Ohm (1W) should be ok.

aarenz2 months ago

Not sure about LED's and electronics but was wondering what it would take to have substantial power supply central place in a house and wire all led lights around house. Would love to remove most outlets and replace with USB connectors to power charging and LED based lighting. You are saying something about the maximum output of the power supply burning out the LED if it is over the rated level for the bulb.

tudurache (author)  aarenz2 months ago

It could be done, but you'll still need a constant current source, for each LED bulb, and this could be more expensive than a phone power supply that you probably already have lying around.

Hinesdarrel2 months ago

Very informative and useful post by you. This can be a very useful to make a cheap but very powerful LED bulbs. There are so many electronics store which offer the best LED bulbs or lights. To get more information you can visit www.analogtechnologies.com .

avedwal3 months ago

u r to good

tudurache (author)  avedwal3 months ago

Thanks my friend :)

en_rov3 months ago

This is amazing. I am just wondering, for safety concerns, how hot does the cell phone charger/power source integrated in the bulb get? I would like to upgrade my desk but am a bit afraid of fires/shorts. Thanks!

tudurache (author)  en_rov3 months ago
Well, I don't see any problem... most of the cell phone chargers contains themselves some protections (short circuit, over temperature) and they are reliable enough (in our office we have few of them plugged non-stop for almost 3 years) and the bulb base is also heat resistant...
There were almost 2 years since I have made my first LED bulbs and all of them worked perfectly since.
en_rov tudurache3 months ago

Thank you for your reply, I am definitely making this. I havo found this leds, http://www.ebay.it/itm/10pcs-3W-5V-700mA-High-Powe... do you think thry would be suitable? I need to light well my desk, so I would like a proper lighting. Thanks in advance

tudurache (author)  en_rov3 months ago

You are welcome! The LEDs are ok, you should use a phone charger with maximum current less than 700mA (maximum current allowed by your LEDs), otherwise the LEDs will have a short lifespan.

vdjondo4 months ago

I great this page.
I was looking for this kind of article as I was planing to do my own testings.
How about using the Balast that allready where in the bulb ? Wouldn't they give enough power to your leds ? How about with small consomption led like 3mm classic white led ?
I feed a Led Page where I copied the adress of your present page. Please like it and share.
https://www.facebook.com/pages/Led-Lighting-Lumi%C...

tudurache (author)  vdjondo4 months ago

As far as I know, the ballast from the CFL bulb gives an initial spike of high voltage in order to initiate the discharge inside the fluorescent tube... it CAN NOT be used to power the leds.

akagrawal3065 months ago

Dear Sir,
I seened your led light bulb projects & was very impressed, please guide me to make a LED Headlight bulb for my Bike- Bajaj Platina 125, it has a 12v 35w/35w halogen lamp & uses a 12v 5LB battery, please guide me if i have to use lense or direct LED or have to make projector or something, also its great if i am able to have a full round angel eye in my head light dome, i am from india, and here leds are just begined to introduced in home lighting, but in auto their is no sign of led head lights here, so kindly plz provide me link for the shop where i buy the parts without any bulk order, sorry for my bad english, waiting for your reply, and Thanks in Advance!

My E-Mail for your reply : akagrawal306@gmail.com

astral_mage7 months ago
the linked is in another langauge . that i dont under stand.
PokeyJoe1 year ago
I love LED and flashlights, I've LED'd my SUV. But something you may need to be aware of, at least in the US. If you DIY something and it causes a fire.. Weather it's a DIY light, a rewired furnace fan, a replaced cord on an appliance..your insurance companies response is that you are out of luck. And believe me they are looking for any reason not to pay. If the item that caused the fire was not a UL approved product, or has been modified in some way, you are assuming the liability. And that includes import products that have a RoHS or SA stamp but not the UL. USA must have UL. Now, I have bought a few of these (http://www.miniinthebox.com/e27-16-led-14w-1300lm-6000k-white-light-spot-bulbs-220v_p338711.html) but ONLY use them in a hand shop light. So just use your head. (great source btw, another is (http://www.mouser.com/search/refine.aspx?N=4292733697&Keyword=XMLBWT-00-0000-0000U20E1)
under writers lab is a joke like the Food And Drud administration is. give the right amount of cash to the right pockets an u can get any thing UL'ed or not UL'ed .
astral_mage7 months ago
http://woodgears.ca/index.html
wood working wonders
astral_mage7 months ago
or better yet go alibaba.com or aliexpress.com both china over view sites. first 1 a collection of company all vaying 4 yr money. the second 1 is more selective on wat they sell.
The Freak10 months ago
First of all, good job! I also got found that +/- 30 euro's for a reasonable led bulb is overpriced, and diy would be the solution. I never thought of using phone chargers, cheap and effective! Not sure what kind of light color you are using, but just so you know, warm white LEDs are available for a more gentle light color. Try ebay for example. Oh and the 12V to power the two xm-l's, wouldn't that fry them, or have you added some resistors or diodes to drop the voltage?
tudurache (author)  The Freak10 months ago
Thanks for the appreciations! 12V for two XMLs is not too much if the power supply is current limited... you see... not the overvoltage fries a LED but the overcurrent... When the voltage rise above 3V for a single XML (6v for two) the current should rise above 2Amps, but if the power supply can not supply more than 2Amps, the generated voltage will decrease. In the same way behaves any constant current generator. Regards!
So you check that by taking a resistor capable of handling the Watts and with a resistance of 1 to 10 ohm? I do not fully understand the method you used for checking the actual max current.
tudurache (author)  The Freak10 months ago
Yes, I used an resistor having a value equivalent with the two LEDs connected in serie. I wanted to power the LEDs with a 2Amps current so the resistor value was: R=U/I=(3V+3V)/2A = 3ohm (value is not critical but must be a power resistor)
I measured the value of the current flowing through this resistor and checked that this is not more than 2-3Amps. Before finding the right power supply I checked three or four power supplies that generated a current above 3Amps even if the specs (written by the manufacturer on the power supplies) were under 2Amps.
Ok I am trying to hook up two 10W 12V 0.9A COB LEDs, to a 12V 2A transformer. Tested the current it delivers to two 2ohm 7W resistors in series, which gave a current of around 2A which is more or less ok. When I hook up this resistor combi in parallel with one of these 10W LEDs it delivers 3A. When I hook up just a single one of those 10W LEDs with a 0.7Ohm resistor the current is only 1A. The weird thing is that if I hook it up to just one of the 2Ohm 7W resistors, it gives 0.1A with the resistor still getting very hot. Also the indicator LED on the transformer starts to flash, so maybe the current starts to go up and down repeatedly so my multimeter won't see the correct amount. Anyway would this be a voltage regulated transformer or something? I think I can work with this transformer just fine but I'm just curious on your thoughts on this situation, since I don't understand what's going on.
tudurache (author)  The Freak7 months ago
Weird... but a wrong measurement i guess...
If you connected in series one LED with one of the 2Ohm resistor and you measured a 0.1Amp current, that means the power in the resistor is 2*0.1=0.2W. An 7W resistor can't be very hot on that power level.
The transformer don't seems to be voltage regulated because when connected to those resistor in series (2*2=4Ohm) you measured 2 Amps and that means 8V. It is possible as you heave said to have an oscillation but you should be able to see this in the light output emitted by the LED. However... 2Ohm in series with each LED for your transformer should be ok. And another thing: try to measure the current by measuring the voltage drop on the resistor and not by connecting the ampermetter series in the circuit because the internal resistance of the ampermetter could influence your measurements. Good luck.
tiMRoni8 months ago
Sir, honest with you the "EVRIKA moment" really helped me...thank you. :-)
This instructable is terribly, terribly unsafe (i.e. death by electrocution)! No name chargers can be very dangerous, and removing one from its case and putting in a light bulb shell makes it even more dangerous. These chargers are often unfused and have terrible creepage. The large screw base and heatsink are large metal parts that could become electrically hot and touched. The openings in the bulb package could let in debris (like a solder ball) and short hot to Vout or ground. See this video to see an analysis of one of these cheap chargers.
Siemens, Samsung, I see names everywhere. No name you say? Though you are right, some of those dirt cheap brandless chargers are a no go. Nonetheless I see insulation tape or shrink tube on every single picture, I'd say he did a good and safe job. The wall socket part is the hot zone, the secondary is not that much of a big hazard if you ask me.
carson01061 year ago
Nice,in fact more and more LED lighting is used in our life,it save ernergy,high-power.More about the LED lamps and other lighting,you can visit the
Web:
http://www.darkon-lighting.com/
Bulb.jpgBulb.jpgBulb.jpg
asharma91 year ago
Amazing instructable sir, ijust wanted to make my lamp with 10+ leds http://www.cree.com/led-components-and-modules/products/high-brightness/5mm-round-p2/5mm-round-white
but Im unable to calculate circuit diagram and power supply to go with it ........im totally new to LED and electronics...
tudurache (author)  asharma91 year ago
These are small power leds... you could use a 5V phone charger and power each led through a 91ohm resistor. A 500mA charger could power 25 LEDs. A simpler option (but less recommended) would be to connect all the LEDs in parallel and power them through a resistor having the value R=1.8/(n*0.02) where n is the number of LEDs. However you should read some basic electronics before diving in this...
Very nice ! I have enjoyed reading the entire Instructable , Thank you!
acruz311 year ago
thanks sir:)
acruz311 year ago
sir can you give me a circuit diagram for this?
tudurache (author)  acruz311 year ago
Sorry for the delay... the diagram is very simple, you can see bellow.
The diode D can be any rectifier or Schottky model that can withstand the required current.
Even I did not used the diodes (my chargers were identical), I recommend you to use them as in the circuit diagram.
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acruz311 year ago
sir thanks:))
acruz311 year ago
Sir i haven't decided yet..but i want to have an output that will light as luminous as 15 W fluorescent lamp..can you give me the characteristics or maybe some techniques or ideas that will help me achieve my goal? tnx
tudurache (author)  acruz311 year ago
You can use an Cree XM-L T6 power LED, powered by two switching power supplies from LG mobile phones, exactly as I have used in the bathroom (Step 7). Each power supply unit can generate according to the manufacturer, a current of 0.9A, but I found the current practically limited to the value of 1A. The two power supplies are connected in parallel for a total current of 2A. If the two power supply are not identical you should connect in serie with each one an 2 Amp diode (any rectifier or schottky diode will work).
Under these conditions the LED will produce a luminous flux of about 700 lumens for a power consumption of 6W, and this is about as much as an 15W fluorescent lamp.
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