Turning a fluorescent bulb into led bulb

Thread Starter

Jonlate

Joined Dec 21, 2017
75
Hi again,
Let me try and explain this, can I change a fluorescent into a led bulb.

In other words can I disconnect the caps from the end of the glass tube, take out the internals of a fluorescent bulb and connect LEDs to the terminals and stick it back together again?

Problems I see are that the fluorescent bulb runs on 240 volts and LEDs don’t.
My fluorescent bulbs plug into a socket, and are not wired directly to the mains, so I could just connect a phone charger (or similar) between the two and run them off this.

Any other problems you may see me coming up against?
Would I wire positive and negative of the LEDs to the inner and outer parts of the fluorescent bulb at both ends, or would only 1 end be okay?

This is the bulb I am working with, I have 3 under the kitchen cupboards, and they have stopped making them this size now.

Any help appreciated.

Thanks

A458A1DA-61B1-4AD0-848E-7472207F366B.jpeg
 

danadak

Joined Mar 10, 2018
3,627
There are a number of considerations, heat, ballast effect, starters, light distribution,
uniformity......

A number of companies went thru a lot of research to make a general purpose
LED replacement in existing fixtures. I once worked with LED Dynamics who
spent some serious resources and engineering to do this. So its not trivial.

Regards, Dana.
 

Glenn Holland

Joined Dec 26, 2014
667
No - A fluorescent tube and fixture cannot be converted to LED.

The power supply (and photonic processes) are drastically different and you must remove the fluorescent fixture from the 110 VAC supply and connect a completely new LED fixture.
 

dendad

Joined Feb 20, 2016
3,084
You can buy off the shelf LED drop in replacements for fluoro tubes. At least is is so here in Australia.
I would advise against trying to make your own. You could burn your house down ;)
It requires removal of the starter and replacement with a dummy of a "LED Fuse", depending on the tube type. The ballast can remain, at least as long as it is a plain old inductor type.
 

MisterBill2

Joined Jan 23, 2018
4,055
You can buy off the shelf LED drop in replacements for fluoro tubes. At least is is so here in Australia.
I would advise against trying to make your own. You could burn your house down ;)
It requires removal of the starter and replacement with a dummy of a "LED Fuse", depending on the tube type. The ballast can remain, at least as long as it is a plain old inductor type.
Fire is far from the major hazard of attempting to even open a fluorescent tube, but rather the glass and the coating inside it. Certainly the voltage and current requirements are VERY FAR APART and so it does not make sense to try. LED replacement bulbs are available, but better yet are the LED light bars that are also available and run directly from 12 volts. Check this one seller, there are many of them, but this one is good: Superbrightleds.com . Not a very imaginative name but they certainly have interesting products.
 

Thread Starter

Jonlate

Joined Dec 21, 2017
75
Thanks all.
Looking at the bulb again, fluorescent is the wrong word to use for the bulb.
As it’s only a short bulb 12 inches long, it’s got a sort of a metal element inside the bulb. It’s looks like a normal light bulb element but as long as the bulb.
So I have no starter or ballast to worry about!!
Here is the same bulb with clear glass, it’s a 240 volt 30 watt bulb.
DD4E57EF-BFB9-48E4-9E4B-28C070CA2AF6.jpeg
 

MisterBill2

Joined Jan 23, 2018
4,055
If iit is a linear glass incandescent bulb, the effort towards any conversion will far exceed the value of what you wind up with. Save those ends and fill a plastic tube with those high output LED surface mount LED things, all connected in series. Then all you need to do is come up with the correct driver circuit, and build it.
 

Thread Starter

Jonlate

Joined Dec 21, 2017
75
]If iit is a linear glass incandescent bulb, the effort towards any conversion will far exceed the value of what you wind up with. Save those ends and fill a plastic tube with those high output LED surface mount LED things, all connected in series. Then all you need to do is come up with the correct driver circuit, and build it.

That’s exactly what I wanted to do, but using the original glass tube instead of a plastic tube, and plug it wiring through a dc charger.
Looking at the glass tube though, I don’t think I will be able to get the ends off without breaking it.
How are these tubes made in the first place? How are the ends connected to the glass tube?

Thanks
 

MisterBill2

Joined Jan 23, 2018
4,055
The glass tubes are extruded from molten glass, and then in a separate process the filament elements are put inside the tube and the ends are heated and sealed in a secondary operation. Then the assembly is evacuated and the evacuation tube id heat sealed in a third production step. The metal ends are usually glued on with a strange very high temperature adhesive. The big deal part is the very high temperatures needed to melt the glass, where it must be hot enough but not too hot.
 
Then the assembly is evacuated and the evacuation tube id heat sealed in a third production step.
I've done rudimentary glass blowing and sealing under vacuum, mostly with quartz and a Hydrogen/Oxygen torch. If I hadn't done it for a while, I'd have to do a practice run first. My start diameter was about a cm.
Surprisingly, I learned quickly and taught my successor.

I watched a tube making video which was really nice for a real company. See https://www.daliborfarny.com/blog/ and http://tubecrafter.com/

If you take a look a a miniature tube, there is a real small area where the vacuum is applied and the tube is sealed.
 
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