Compact Fluorescent Lamp(CFL) is becoming popular day by day because of its ease of instillation and low power requirements.They have a fairly good life of about 2 to 2.5 years depending on use. I was having 4 dead CFLs and was wondering how I can recycle them. I got an idea to make Compact LED Lamp (CLL) from them. Read out my instructable to get to know how to make a CLL from dead CFL. Its easy, economic & fast. It took less than hour for me to make a CLL. So lets start.....
Step 1: What We Need ?
We need the following material to make a CLL
1) Dead CFL(s)
2) Bright White LEDs having such size so that they can fit into the bore of tube of CFL.
3)Solder & Soldering Gun
4) A power supply (discussed in detail in notes).
5) Screwdriver, hammer, hacksaw, adhesive, adhesive tape, etc.
Step 2: Lets Get to the Work
Now, first of all we need to open the dead CFL and remove the ballast circuit in it. First remove the end connecting cap by screwdriver as shown in photos and disconnect wires. Then try to open the upper portion of the plastic assembly that holds the glass tube. It is anchored in the base plastic assembly that holds the ballast circuit. For some CFLs these two may be sealed with adhesive. Try to open them by screwdriver so that anchoring releases or simply use hacksaw to separate then as I used, Be careful while using hacksaw, cut it in circular fashion not from top to down. When you complete separate 3 parts of CFL, cut down wires connected to glass tube and remove ballast(choke) circuit from the middle part.
Step 3: Breaking the Opening of Glass Tube
This part is very important and risky too. If you got a CFL of 11 W (As I used here), it contains main two tubes. No of tubes may be more for more CFL having more wattage. But there will be only 2 electrodes. We need to take these electrodes out. Using a wire stripper break the uphaving glass part of electrode. It may fall down in the tube. Make tube vertical so that it comes down again. Using screwdriver or any tool u find suitable make small pieces of electrode by breaking it in the tube so it comes out totally. No part of electrode, especially metal wire should remain in the tube. Don't strike screwdriver on inner walls of the tube as it will remove the inner fluorescent coating. Once you remove both the electrodes, you get two openings to tube. Broaden them carefully so that your LED can enter it.
Now for remaining you need to be careful. For CFL used here, there are two totally sealed bottoms of tube that we need to break. Use a sharp nail or screwdriver and gently break it by hammer. Be gentle, this could break the whole tube. So finally, you should have opening for every section of tube from bottom.
Step 4: Arrange the LEDs
Now the part comes to arrange LEDs. Connect your soldering gun to AC supply and get ready. You can choose any no of LEDs depending on the length of dead CFL you are using and your light requirements. I have used total 24 LEDs here as 6 LEDs in each tube bore. You can either use series of parallel connection. Parallel connection would require huge reisistance to connect with it. Also it may not fit in the tube bore. So I prefer series connection.
As illustrated in photos, get rough idea of how much should be space between two LEDs. I have kept space of about 1 cm between two. Then cut extra leads and go on soldering. Make bunch of 6 LEDs (or any no you want) in total 4 (equal to total number of tube bores). You need to connect a wire to lead of LED that goes innermost in the bore to connect it further.Insert every bunch in tube bore very carefully. Make the connection of all LEDs so that they are as per shown in circuit diagram. Finally you should have all the LED bunches in the bore of tube and only two connecting wires coming out.
Step 5: The Power Supply
Hmm.......the tricky part now comes. You can run LEDs directly on AC supply as they itself rectify the AC, however this is risky and reduces life of LED.I have used a bridge rectifier to improve life. You must connect appropriate series resistance. To calculate series resinstance-
I have 24 LEDs in series.
Max voltage drop in each LED = 3V & current is about 20mA ( for LEDs I used, this may differ, refer datasheet of provider or estimate by multimeter)
for 24 LEDs 3*24= 72V
AC supply available at me = 230V
Voltage to be dropped in resistance= 230-74=156 V
Hence for me approx. 8 to 10 K resistance will be needed. I have used 10K resistance.
Assemble power supply as shown in circuit, which is very simple. If you don't get ready made bridge rectifier, make it by using 1N4007 or similar diode.
1) Working with AC is risky. Using such type of power supply will reduce the life of LEDs.
2) Using a DC supply containing step down transformer, filter & regulator is advisable. Or solid state transformer less pure DC supply circuit will do.
3) You need to design power supply according to input voltage available at you.
Step 6: Gather It Together.
Finally, connect the glass assembly to output of power supply. Extend wires of end cap if needed and connect them to power supply. Connect the end cap. Use adhesive and tape to join the plastic assembly. Its DONE ! Get ready for testing.
I suggest you to use small car inverter or a UPS or a home inverter for testing. Do not use AC mains directly for testing. If everything goes fine, its okay to use with AC mains.
Step 7: Compact LED Lamp Is in Your Hand !
So finally we have made dead CFL working again by using LEDs. The CLL I made consumes about 6W only. It is enough to light up a small room or porch or balcony. Better the power supply you use, better the life of CLL. It costs almost nothing. I needed to spend only 70INR (about 1.5USD) to make this. Let's recycle dead CFLs to CLLs !
This method can be also applied for Standard Fluorescent Tubes. Bulky ballast assembly can be replaced by power supply circuit. Only the thing is it is very fragile to open end caps of the tube.
If you want to create LED Bulb, you need to carefully open and remove filament in incandescent bulb. Also you need to add a reflected behind of LEDs.