Introduction: Cheap LED Retrofitting

Ah! In this instructable i will describe how you can convert those old small tube lights in better and more efficient LED Lights that doesn`t even hurt your pocket!
As we all know LED`s are - good, long lasting,efficient and easy to play with!

Let me share a small anecdote:
I had this really small sized Tube light that i used during some late night reading. It served me good for about 2 years and then it would abruptly close down after a few minutes. It had those so-called power efficient electronic chokes to start and drive it. After a  quick run to the spares shop to get a replacement choke for my light, i found out that , these  chokes are no longer in stock (Mine was a low power one, higher ones were still available). Adamant, i came back home and decided to replace it with a LED Replacement.

So, to get started you will need :

Electronics:
LED`s (3x1 Watt) (Moon White/Warm White)
Wires
LED Driver (You build you own too using either a ac stepdown transformer with a Buck Conv. or Linear Regulator( Less Efficient))
I decided to buy one because the cost of building one was somehow more than the product.
These are readily available on the internet
like this , this or this . I managed to find a local source for the same, who after some bargain was willing to sell it to me for about 2.2$ . If anybody needs it in India, they can surely ask! :D

Tools:
Screw Driver
Drilling Machine
Wire Cutter
Heat Shrinks
Soldering Iron


Mechanical Stuff:
Screws
Steel sheet (for making a heat sink)
Heat Glue 
Butter Paper 

Just the above materials and you are all set for making a LED RetroFit!

COST:
So, i just too me about 2.2$ for the driver and LED`s worth 1.4$, which is 3.6$
To resurrect an old Tube Lamp into a modern day LED Lamp!

Just in case you don`t have a similar model, the instructable still applies, as you make use of several tricks i used in any of your high power LED Project! 



Step 1: Crack Open the Tube!

Now just crack open the case with some screw drivers and other related tools. You will find the choke there thats driving the tube!
Carefully cut the wires, leaving the switch intact,
Then remove the Choke and the screw away the small connector for the Tube.
The back surface if sufficiently silvery, do not remove it, it reflects some light! 

In the next step, we will see how to fit LED`s there!!


Step 2: LED In- CFL Tube Out!

The driver is rated 12V, and can drive 3 LEDs in a series fashion.
The current is about 350mA, thats enough to produce the maximum intensity from the LED.
 First i tested the circuit and soldered all these 1W LED`s in series , just to get a feel of the brightness it could produce.

Next we need to screw these LED`s on the shiny surface. 
Drill some holes and use some screws to firmly bind the LED`s in place.
Do not use any glue, this is because LED`s can get really hot and in that case the glue might melt.

Also drill a few holes to take the wire backwards! 

Step 3: Butter Paper Trick!

Now, here comes the part 1 of the fun,
LED Intensity is too high to be viewed directly, this is because they are essentially point source and constant looking may cause strain. So, commercially they use these special quality Plastic Injection molded Diffusers ( yeah! they are called diffusers ) .
But , i thought that friendly butter paper would be of great use here.
So i cut out a strip from the butter paper and taped it to the front grill of the Tube.
It works really great, and almost like those industrial quality ones!


It diffuses the light quite effectively and prevents that high intensity problems!

Step 4: It Heats a Lot!

I initially over estimated the capability of the internal heat sink of these LED`s, but after a few hours of operation, i found that they would become very hot. 
So, i worked out an easy to make heat sink. just cut a strip from the steel sheet you can easily get at hardware store and place it as shown in the picture,
The frills like structure , increase the dissipation area and cool down the LEDs by taking heat from inside to the outside.

I have never had a problem with this light in the 6 months of operation till date!

Step 5: Pack UP and Install!

Now, i just packed it up and installed it where it was installed previously!

This ends the instructable!

Hope you like it ! :D
Any questions are welcome and please do vote!

Comments

author
krishna.cool.94849 (author)2015-05-22

The way you have connected the LEDs is not exactly right........ Each LED (white) requires 3.2 v to work..... With a maximum current in your case of 350mA........but you are supplying....4v to each led which is greater then it's critical voltage of 3.6v...... And the current can vary according to the capacity of your LED driver...... So i suggest you use a current limiting resistor with 6.8 ohm resistance....... The resistance is calculated like this resistance={12-[3×3.2]}÷(350×10^-3)

author

Hi,
You are correct. But in my case the voltage of the driver on No Load conditions and full load condition is not same. When completely loaded the voltage drops down to about 10V and hence adding a resistance would have been useless in that case.

author

Oh........ Okay then. ^^

author
thebriguy (author)2014-11-26

I found you can just rough sand the 'lens' (bulb cover) and that diffuses the light. You have to judge if you would still need the butter paper :-)

Thanks for the instructable

author
bhvm (author)2013-09-01

very nice work. butter paper diffusion is a great Idea. please give your views on my project- https://www.instructables.com/id/Transform-a-boring-old-Table-lamp-into-2800-Lumen-/step4/wicked-2800-Lumens-of-Retina-burning-power/

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Bio: Im a freelance electronics designer who loves to do photography and spends the day working for his college Solar Car Team apart from studying the ... More »
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