How To Wire Up Ccfl To 12V Adapter

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markopolo

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Hi.

I want to wire up 2 x CCFL to a 12V 'wall wart' adapter.

I've researched this for about 8 or 9 hours now and have come across all types of advice of whether this is even possible or not. Some people say that it can't even be done and you need an actual computer PSU to do this. Others seem to be confused by the fact that there are two tubes working off of one inverter, or if they are clear on it, the advice they give for wiring it up is confusing.

Ok. Let's give some specifics:

CCFLs I am using: http://www.ebay.co.uk/itm/WHITE-12-DUAL-COLD-CATHODE-LIGHT-KIT-MOD-CASE-PC-Computer-CCFL-Very-Bright-/380375886930

I have 2 of these kits, making that 4 'tube lights' in total, run off 2 inverters.

PSU I am attempting to use: http://www.amazon.co.uk/Universal-adapter-1000-mains-plug-Black/dp/B008F86R1A

Power Input: 0.25A

Power Output: 1A

It has variable 'V', but obviously I will be running it at the 12V setting.

Here is a photo of the actual CCFL kit, with the inverter a sky blue colour: http://electronics.stackexchange.com/questions/24162/conversion-of-a-cold-cathode-kit-to-work-outside-a-pc

Also on that page is some advice for hooking it all up. But again there are discrepancies in regard to exact specifics, because of the confusion surrounding one inverter powering 2 x Light Tubes. I have links to about another half a dozen pages covering this exact same issue, and I'm still confused, so I'll not confuse things more by posting them here.

This post seems to give the best and most straightforward advice for what I want to achieve: http://www.tomshardware.co.uk/forum/304703-28-cathode-tubes-supply - but I am still not sure exactly what I need to do. This is one thing I don't want to mess up.

So, these are my specific questions:

1: Is that PSU adapter sufficient to power 2 X CCFL kits (4 'Light Tubes' + 2 inverters total)?

2: If so, which wires do I need to 'splice' from the CCFL kit (which colour) to the PSU?

3: What would be the correct way to connect the 2 kits together (they come with Molex adapters)?

With regard to no.1, my specific PSU is either amply powered or under powered, depending on whether you consider the power draw to be from each 'Light Tube', or just from the single inverter. Yes, it's confusing.

With regard to no.2, the post at Tom's Hardware (linked above) says this "Splice the yellow lead from the wiring assembly to the positive lead of the AC to DC adapter and the black lead from the wiring assembly to the negative/ground lead of the AC to DC adapter." But even if it is actually this simple, which 'lead' out of the PSU is negative/ground? One lead is coloured black, the other is black with a white stripe down it.

With regard to to no.3, I have been told (in my research) that these need to be wired in parallel. There is only really one way the two Molex adapters can be joined, and I am assuming that one would connect them via black to black, yellow to yellow, red to red etc. rather than the other way around. I will post a photo of them connected together if it makes it easier to visualise.

----------------------------------------

If you'd like to know what I'm trying to do all this for, it's for some concealed lighting in my studio, to put under some shelving to throw a bit of light on my keyboards and controllers. I have researched this like I said, even studying and understanding the electrical theory behind it all, doing my own calculations etc. to an extent to at least understand the equations that people have given. But as to the actual practicality of wiring this all up, I'm none the wiser. I started about 7am this morning, and in fact researched this for a day or two a couple of months ago (but I had to put it on hold), so I'm kind of at the stage where I need a little help.

Anyway, any advice is appreciated, and if there is some stuff I haven't thought of or information I've omitted, please let me know.

Thanks.

 
A ccfl operates from a high voltage, so to get it to work from 12V you need an inverter, which I think is what the kits you link to is.

But I have to question WHY you want to run them from a wall wart PSU?

If you want to run it in a building from a mains supply, then make your life simple and buy ccfl fittings designed to operate directly from the mains. The sort that go under kitchen wall cupboards would be a good place to start.

If for some reason you really want to run them from 12V then get a ccfl fitting designed for a caravan. You will then just have to check the manufacurers rating of how many amps it requires to determine if your wall wart will power one or more of them.

 
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We used these guys http://www.a1designs.co.uk/  a lot, but have not  had a need for a while Very helpful  and would make the tubes to our spec.
Thanks.

I already have the two kits and they pretty much cover what I want to do, in the space I have.

Good to know though for when I get things a bit more advanced towards rigging everything up.

This has been a major pain to get any solid info. I have a degree in computing but this sort of thing is alien to me.

Using your fellas would have probably been a better idea. The time I've spent on this is getting a bit silly. I managed to rig up to 2 computer fans to a 12V adapter in a few hours researching on the net (with it all working perfectly and not blowing up so far six months later). But this inverter thing is what's confusing the issue. The maths is straightforward, but people are confused as to whether the manufacturers specs are per inverter, or per 2 x light tubes running off one inverter. The difference is marginal, but crucial. Also, a few tutorials by people that really know what they are doing are saying these things are 5W each, not 3.4 as per the proper calculations. Which would bring the total up to 20W, and some people are even saying you need to use a proper computer PSU - 300W jobbies - kind of thing. That is quite a large margin of error. Others are saying to buy a laptop PSU which is inbetween those 2 examples obviously power wise.

The most examples given though seem to think that they can be run easily off a single PSU adapter such as I have. Or accounting for the 'inverter/2 light tube' confusion, one that runs as 2A instead of my 1A.  I have calculated that I only need 0.556 of an Amp, leaving me headroom, but again this depends on whether the figures given are per inverter or per no. of light tubes drawing power.

This guy seemed to know what he was talking about, so I followed his calculations:

------------------------------------------

27_98a8994266fc3456c2523dede5ca74e0.png

27_e8ae004d01986c7ce2566f5dad769c81.png

Total current is,

22_7020944c581fcbc814b5cc1339791174.png

------------------------------------------------
 
I substituted the 3 for my 2 (the guy that was asking the question wanted to use 3 kits) and came up with that figure - 0.556 (sorry, I forget the exact abbreviation for it now, but you know - percentage of an Amp).
 
Then again, when you see how others work it out, the figures vary, though they obviously always use the same methods of calculation which are universal. That's what is totally confusing me, nobody has ever came back and set it works, or it didn't and it blew up. I guess they just gave up. Then again, I've seen a lot of people get this rigged up with photos, it's just that they never say how they did it.
 
I guess the big question that solves all of this is, are those figures given (in my link to the CCFL kits) per inverter or do they need to be doubled because it is firing 2 light tubes? I'm a total noob with this stuff, but others that obviously know what they are talking about, are confused as well.
 
It's not a big deal. I'll either chuck it all in the bin or pay an electrician to come out to do it for me. He'd probably look at me a bit funny and charge the earth, but it would be worth it just to get to the bottom of this great mystery. I can't imagine him turning around to me and saying 'sorry' I don't know how to do it. It's just so confusing trying to explain things or understand things without clear information.
 
Anyway, thanks again.
 
A ccfl operates from a high voltage, so to get it to work from 12V you need an inverter, which I think is what the kits you link to is.

But I have to question WHY you want to run them from a wall wart PSU?

If you want to run it in a building from a mains supply, then make your life simple and buy ccfl fittings designed to operate directly from the mains. The sort that go under kitchen wall cupboards would be a good place to start.

If for some reason you really want to run them from 12V then get a ccfl fitting designed for a caravan. You will then just have to check the manufacurers rating of how many amps it requires to determine if your wall wart will power one or more of them.
Hi.

Yes, the inverters are included in the kits. The reason I want to use the wall wart PSU is coz I have one spare, after buying it on initial advice that that was what was needed to power these two kits (4 light tubes/2inverters). But I know nothing about electronics though I can build and program a computer. Well, next to nothing, obviously with a first class degree, I know a little bit, but assembling a computer from parts is a lot simpler than what I'm trying to do here. I could have actually built a computer and had an OS set up on it with the amount of research I have done on this so far. I'm just checking and double-checking that this is not going to blow the equipment or me up.

Also, I am trying to learn about electrical stuff, and I'm studying as I go along. It's been a great project and it's helped me to fill in a lot of gaps, so no regrets. I'm not even frustrated really, I'm determined to see it through. My aim is to learn enough so that I can safely design and work out schematics for the lighting in my studio (amongst other things) and then finally give that to a proper electrician to come in and do the dirty work, so to speak. I figure he'd be more than happy to follow a well  designed schematic, than have to make someone else's decisions for them. Thats' the idea anyway.

I'm also in the process for building my own Light Box for photography and 3D CAD, in fact I have actually built a very crude but working prototype with several interchangeable CFLs (not CCFLs to be clear) and a couple of computer fans in there as well for cooling. And I'd like to extend that out with using CCFLs (though apparently they don't run much cooler than CFLs all things being equal) as they come in a variety of colours. So it's not just this one random thing I am trying to do here, though this seems like as good a place as any to start.

I'm quite happy to reconsider things, and I'm quite happy to buy a laptop PSU or even a proper 300W computer PSU with multiple rails - they are all cheap enough - you can get a 500W one for 15quid!

And don't even get me started on the difficulty of working out stuff like Lumens. There are even greater orders of magnitude in difference with various people working that out 'scientifically' as well. Most people just say 'oh it's not really possible to work it out accurately'. Not half!

To be fair, I got a lot of information from certain, shall we say 'horticultural' sources, that may or may not have been getting high on their own supply, so no wonder they were confused!

Besides, even when I figure this little conundrum out, I'd like to do a proper job with connecting the splices up, and I guess that would involve a bit of soldering and crimping and whatnot - I don't know - I haven't really looked into that seriously yet. I mean, it's not like I'm trying to rewire the house or anything. I'll leave the heavy lifting to the pros, but how difficult does this need to be, to do it well and do it safely?

Anyhow, thanks for the reply. Hopefully my little ramble explains a bit better where I'm coming from. I actually feel confident enough to rely on the science I already know to work this out, but maybe an email to the manufacturer of the kit to specify the exact facts and figures, is in order first before I plug anything in - that's the real stumbling block here.

Cheers.

 
Have you considered using LED's or LED strip? I understand that you have the lamps already, but LED's would be much easier and less to go wrong

take your pick and they would run from the wall wart you have.

 
Connect 1 of the lights to your power supply and measure the current it takes (buy a cheap digital multimeter for £5 if you don't have one) Then you will see how much they really take and work out if it can supply all 3.

 
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Have you considered using LED's or LED strip? I understand that you have the lamps already, but LED's would be much easier and less to go wrong

take your pick and they would run from the wall wart you have.

Actually, that was my next question. I have a few silly little LED strips (the bendy ones) just for experimentation purposes as well. They actually come with some instructions. I was thinking it might just be easier to use the wall wart I have for these and get a 2A 12V PSU adapter that should cover me for the CCFLs (even if it is double the estimate).

These are the LED strips I have:

http://www.ebay.co.uk/itm/Pack-of-4-White-LED-Strip-Lights-12V-DC-for-Cars-Caravans-Boats-SWB-Vans-10cm-/121356304427

But first I would like to figure this problem out. I get to a point where I have spent so much time that it feels like 'giving up' if I don't work it out. Dog with a bone kind of thing. I've already decided to cut my losses though, and am only interested in this now from a purely academic point of view, for use later on.

Regarding the CCFLs:

I'm actually going to go on the calculation, that those figures given for the CCFL is per inverter.

---------

Input voltage of inverter - 12v

Output voltage of inverter - 680v

Current Draw - 5.0 mAv

-----------

So that would be:

P = 680 x 0.005 = 3.4W

I = 3.4/12 = 0.283A

Total current is:

0.283 x 2 = 0.566A

..................

That would be according to that random bloke's calculations, which seem to be the most common way of working this out that I have seen. He also had nearly 15,000 posts there at that forum (before he got banned), so I assume that he knows his onions a bit. The OP never got back to him which either means he blew himself up, or that it worked and he's an ungrateful so and so like most people on the net.

Here is the link if you are interested: http://www.electro-tech-online.com/threads/cold-cathode-lighting-project.23819/

Of course, with my wall wart only being 1A rated, if that was per Light Tube (2 per inverter), then that would be over, and as I understand it trying to draw more current than the PSU can provide, which is a _bad_ thing. If I had a 2A rated PSU, then I am definitely covered. Or so I believe right now. Where those guys got the idea for 300W computer PSUs from is beyond me, but then again, I can understand it when some chaps were hooking together 10-20 of the things and using just one inverter per CCFL tube, for slightly increased luminosity (these were the horticulturists growing plants).

Btw, I still have no idea how I would hook up those 4 LED strips I have. I am pretty sure my PSU would cover me for that, but as to the actual wiring, again, I'm at a total loss. It would be good to at least figure this out, because then I can just ad hoc set up the odd LED strip or CCFL where I need it as I move my studio about. I have a bigger studio elsewhere that I use, and that is where the proper electrician would come in.

I really am a total noob with all of this. But this is very interesting to me and I am trying to learn. I'm actually not that bright, and failed at becoming a computer programmer. But there is a certain satisfaction that comes from learning one's limits, or indeed, finding out where those limits might lie.

Thanks for the help.

 
Connect 1 of the lights to your power supply and measure the current it takes (buy a cheap digital multimeter for £5 if you don't have one) Then you will see how much they really take and work out if it can supply all 3.

Ah yes, a Multimeter. I have heard of it.

That was what someone else advised along the way as well. I suppose that is the best thing.

The inverter supplies 2 X CCFL light tubes, but these can be swapped out so it would be possible to just test one. I still have no idea apart from the advice given on Tom's hardware about how to wire it..

"Splice the yellow lead from the wiring assembly to the positive lead of the AC to DC adapter and the black lead from the wiring assembly to the negative/ground lead of the AC to DC adapter."

But again, I'm such a simpleton, I don't even know which one is which from the PSU. I am assuming that all black corresponds to black, and the one with the stripe down it is the 'other' one. That probably gives you a good chuckle. There was me bragging earlier about my degree, and here I am now admitting that I don't effectively know how to wire a plug! Ha!

There is a name for it, that I forget now, to class the pyschological concept of when someone is so well versed in a subject that it is second nature to them, and they assume that others must have a similar level of understanding. You would be wrong. I know nothing. I freely admit to being an 'idiot' so to speak. It's ok, I'm picking up quickly as I go along. It actually took me an hour or two to work out that equation that the bloke gave earlier (the one with 15,000 posts who got banned), but I got there in the end.

But anyway, yes, a multimeter. I'll get one.

I've a feeling I might be popping back from time to time in this thread to ask a few questions...

 
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