Print PDF
Favorite
Email
LEDs could be very efficient and economical in long term use. A 10W LED lamp can replace a 100w incandescent lamp or a 30W compact fluorescent lamp. Despite an relatively high initial cost, compared with other kinds of domestic lamps, your electric bill could drop significantly if you use it instead.
Here I will show to you how to make your own stylish 10W Retro-Futuristic LED Lamp, spending around US$ 25 bucks. Let's go!
Remove these ads by
Signing UpStep 1Materials
You will need:
1. One old burned compact fluorescent lamp, for the LED lamp socket (anyone serves);
2. Two grip flat connectors;
3. One 10W LED: www.satisled.com/10w-high-power-led-white-600800lm_p134.html - color of your choice;
4. Two little screws (search in your tech scrap);
5. One 10W LED driver: www.satistronics.com/constant-current-power-supply-for-10-w-power-led-100240vac-input_p2174.html
6. Thermal paste;
7. One old computer cooler (search in your tech scrap);
8. Heat shrink tubing;
9. 30 cm of wire (2 mm).
| « Previous Step | Download PDFView All Steps | Next Step » |
its my understanding that the bulbs burn quicker than the components behind them.
Nice design , too , but there's one thing , add a cover like those ceiling CFL's have , or else somebody's gonna go blind looking at it , for real .
How about installing a fan too ? It might get hot , why not ;) especially if you encase the cooling fin in a case , i might be wrong , but you could correct me .
The heat sink was from an old CPU cooler with integral fan.
without the fan , junction temperature was recorded as 140 F.
As soon as the fan kicked on, it dropped down to room temp, ie 70 F.
Thanks for the info.
Sree...
The diffuser have the function to soften the light, and it's ok. These LED is really very bright and there are many other options to diffuse his light. I choose a very cheap.
The fan is not necessary, if the cooler is exposed. It reaches 53 Celsius, and the LED supports it. Don't close this thing with a case or it will fry. In this case, the fan is mandatory.
Further, I cannot recommend using the generic power supply linked, it appears to not be UL listed and may be unsafe. I would be glad to be wrong though, if you will provide the CE and FCC certificates for it that are implied by the stamps on its label and a proof that the components are the same as submitted for the certification.
Further, mounting the power supply above the heatsink will heat it up, I would be worried about it causing a fire.
Thank you Instructables for the spell checker.........
Best regards
Thank you for your interest in my article. Of course that you can quote it in your blog. I'm working in other projects with your LEDs and I will send the link to you when they are finished.
Thanks for the 10w LED too!
IF the specs are true the lumens for this LED are actually pretty good as its getting 60 to 90 lumens per watt. 60 is pretty bad but if you get a few at 90 thats pretty good actually.
The warm CFL I have in my hands is 900lumens for 13 watts. or 69 lumens per watt so unless I get a few sucky 600lumen LED's these are superior to your average CFL.
Its superior again because the light is directional. ALL the 900 lumens go in the same direction instead of "all around" like the CFL. so if your usage is set up to take advantage of that its that much more efficient than the CFL.
I have about half the house converted to LED. This might let me convert the rest so I just might build one of these and see what happens.
yes these can get 50k hours if you under burn them a little bit. even 40k hours would mean around 40 years of usage.
how would it "know" otherwise?
another trick with LED's is multiple fixtures all crossing each other. Eliminates the hash shadows.
10W Cool and Warm White: 9.73 V x 0.94 A (9.15W)
LED's are Current Hungry. the whole REASON you need to use "fixed current" power supplies with an LED is because as it gets HOT (and they DO get hot 80% of the power comes out as heat) they increase in resistance. as the resistance increases they draw MORE CURRENT which makes them hotter which makes them draw MORE current which makes them hotter.
you get the idea. eventually you get a run away effect and they DIE as they "melt down"
this is the whole reason you have to RESTRICT the current to the LED and this is the whole reason so many Mass Produced LED bulbs DIE far far before they need to (over driven to make them brighter)
so running a 900mah LED at 1000mah won't make it blow up but IT WILL shorten its lifespan.
You plug a 100mah LED into a 1000mah power supply that LED IS DEAD and FAST.
Running it (the 900mah led) at 800mah will LENGTHEN its lifespan while only losing a tiny bit of lumens.
unless "something else" in the loop is restricting the current somehow if you plug a 900mah led into a 1000mah power supply IT WILL EVENTUALLY DRAW 1000mah from that power supply especially in the summer or unless you really go crazy on the cooling.
its LED 101.
9.15watt is nice. How long was it running and how hot was it when you measured that? how hot did the actual emitter get? Lumens from that?
I want LED for the low cost low power and MOST IMPORTANT to me. LONG TIME. I would rather have a dimmer product where I use TWO to get more lumens and have it outlive me than have a brighter product that dies in 10 years.
There are 2 usual ways to run any LED.
Constant voltage and vary/limit current. This is done with lower powered LEDs where currents are from 10mA to 30mA. Usually use a resistor to limit the current and drop the voltage across the LED to 2 - 3V depending on type of LED. If a white LED needs 3V and 20mA to light at full brightness, and supply voltage is 5V. Resistor is (5V - 3V)/20mA = 100 Ohms. Resistor will dissipate 40mW of power.
Constant current and vary/limit the voltage. This is usually used for high power LEDs. Using the other method (constant voltage) with a resistor would dissipate too much power. The 10W LED needs 900mA at about 11V for full brightness. At 12V supply you would need a 1 Ohm 1Watt resistor. Since the supply may vary you might need to run at say 15V. That will be about 4.5 Ohms at 3.6 Watts. If you are using mains power a proper constant current circuit is the only practical solution. These high power LEDs are more sensitive to overload and need proper regulation with an active circuit.
A LED driver should sense both current and voltage and not exceed the 10W to protect the LED. Notice the measurments Lindsley made, they are in line with the LEDs specifications. In fact the voltage seems to be a bit low and the current slightly high. I'd say that is due to the meter/s affecting the circuit when making the measurements or the variations of components.
To get less current you would need to get an 8W driver. The 8W drivers I've found only put out 350mA and so will only give a very dim light, if at all on a 10W LED.
As for long life, from what I can find the LEDs could last 30,000 to 60,000 hours of continuous use. That's 3 to 6 years continuous or 10 to 20 years at 8 hous use per day. Even if the life is shortened by slightly incorrect driving you would still get many years of service, with huge power savings.
The resistance of the LED actually decreases when they hot, so the current increases.
How the driver limits the current?
as for how the driver works. I have no idea.
as fot temps ahh NO if that temp is celsius its way way way too hot.
anything over 100' F or 38' C is way too hot for a White LED. you wil start burning away the phosphorus at temps over 100' F
if your emitter is running 80C or 176" F its NOT going to last long (two months is not long LONG is 40 years) unless its a VERY different emitter than your typical white LED.
once you hit 100' 38c you start to degrade the phosphor. this is why "bad" led's die and why they die faster in the summer.
NOW this is not your normal drop led its a truer emitter so it may be able to handle higher temps. but my Normal LED's I do not let them run more than 5' above ambient.
hotter = more resistance. More resistance = more heat.
more heat equals yet more resistance.
your equation does not factor temperature. you equation is for when CURRENT and RESISTANCE intermingle.
LED's RESISTANCE AND TEMPERATURE mingle and a side effect of that mingling is more temp equals more resistance which means more current demand.
as an led overheats it's junction allows more current through which causes it to explode or melt down.
I hope i helped a little bit
why does a lower rated resistor get hot faster than a high rated resistor when connected to a power source? of course the resistor with less resistance draws more current. how is an LED different?
nerys says:
but not if the resistance increases HEAT which increased resistance and increases power demand.
now incandescent light bulbs have an increased resistance once the tungsten filament is heated up but there is no runaway overheating because of it because increased resistance = reduced current.
lindsley and switch62 seem to correspond to what I thought I knew about leds.