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Forum Index : Electronics : New life for dead 12v compact fluro
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hiya Several months ago I bought a couple 12v compact fluro's to serve as yard lights. I have a controller that switches these on at night, and they run from my 12v system. 
They worked ok for a few months, but soon the tubes became very weak and dim. Just for the sake of it, I pulled one apart and checked the circuit board. It looked OK, no signs of heat stress in these Nelson branded units, unlike other brands which I've seen full of dry joints and basically cooked. So as an experiment I conneced up a 24inch fluro tube to the circuit board, and it worked perfectly 
I've had one of these 24inch fluro / circuit board combinations in use for several weeks now, with no problems so far. It draws about 0.8 amps, and gives off much better light than the original compact fluro tube ever did. I had a 48inch light fitting that was pretty sad, rusty and the ballast was ready to fall apart, so I cut it up and pop riveted it back together to suit the shorter 24inch tube. Then I mounted the circuit board in the fitting. 
And this is the result. The cover isn't on in this photo. 
It's giving off about 10 watts of light, and runs cool, so I expect it to last years, and I have the bonus of a easily replaceable tube. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Just adding, these 12v dc compact fluro's usually have a full wave 4 diode bridge on the input, so it doesn't matter which way the bulb is connected. I removed 3 diodes and bridged one diode location, so it was ony a single wave. This means when I connect it up and it doens't work, I need to reverse the connections. The single diode protects the circuit if its conneced wrong, and by removing a series diode we gain 0.6 volts to the inverter section, which will make the light slightly brighter. I have also tried this with a 48inch tube. Current rises to 1.2 amps, so we are getting about 14 watts light, give or take a watt or two. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Glenn, I have not seen these 12V CFL's yet but what I see in your first picture has me worried. The base appears to use an Edison screw connection just like the 240V types use. Is it different enough so it cannot be confused or did I read your message wrong and the thing actually runs of 240V AC and has a converter inside the base for 12V? You did mention its a 12V compact fluro.....  Klaus |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yes Tinker thats right, its a 12v fluro with a standard Edison screw connection. So yes, it could be fitted to a 240v powered socket by mistake. There is a little fuse in line with the circuit board, so I expect it would blow quickly and the bulb rendered dead. I've had other 12v compact fluros ( from Jaycar ) that have a smaller screw fitting, so these would be less likely fitted to the wrong socket. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| aargee Senior Member  Joined: 21/08/2008 Location: AustraliaPosts: 255 |
Well done Glenn, I love a good (useful) hack! How does it compare with the original 240V? I've got an old Dick Smith kit 12V flouro inverter that we use camping (the ones that run a 36" standard single flourescent tube) and they draw 3-3.5A - but the light output is the full 30 odd watts. - Rob. For crying out loud, all I wanted to do was flash this blasted LED. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I would say its about half intensity, but its hard to tell really without a lux meter. Its brighter that I expected, I would have no problem reading a book within 5 meters of it. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
That's interesting. I think somebody in the design department did not do their homework. One might just as well fit 3 pin 240V power plugs to connect 12V equipment  .
I do hope they printed a big warning label on the package. Klaus |
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