Will a CFL work on 12V ?

[willib]

with Fall coming soon and the need for more light

i finally decided to try to run a CFL bulb on 12v

the bulb had two terminals at either end , but just using one terminal per end seemed to work just as well

i am not up on my flouro bulbs , but the unit was built for a 11.3" bulb (F8-5)

but the bulb in the last pic is a (F6-T5CW) for comparison with the CFL

since i didnt have a bulb with burnt electronics i had to use a working one , and it works!!

The pics were taken with the flash on

for comparison i put the T5 bulb back in , to me it looked as bright as the CFL but the reflector behind the T5 bulb makes it look brighter?

it didnt light right away ,i could see it was trying to warm up ,i tapped it and it started to light

[willib]

almost forgot,  the unit has an auto accessery plug on the end  and is running off of 12V  

[dinges]

Willib,

Do you have the driver circuit for the CFL? Is the circuit homebuilt, or connected to a commercial FL driver?

Very interested myself. I am NOT going to pay the 20$ for a 12V CFL. Converting a 220VAC one is the only option at the moment. You know of Commanda's driver circuit?

http://www.fieldlines.com/story/2005/6/3/62548/82431

Also have some 6W FL drivers from old scanners. They might work with low-power CFLs too, perhaps.

[stephent]

Several circuits for using flourscents (CFL's too I would suppose) on 12 volts on the Internet.

http://www.smallsolar.org/hardware/fluoro/circuit.htm

Most newer lamps (T8's and T5's) will light on these type circuits if the total wattage

doesn't exceed the semi's ratings.

I suppose it would be possible to cannibalize an electronic 120volt ballast and rehook it to do higher boost with most of the stock parts and just adding a couple more--??

Haven't even looked at one with that in mind.

Might be something to ponder on when I get some time. But most are potted in a gummy type wax?? or tar  (probably not tar) substance, but it's fairly easy to dig off.

I'm digging one "out" of that stuff now.

 

[willib]

i bought the unit at Kmart and the CFL at the dollar store

the CFL was 120V , till i took it apart

i have been doing some reading on them the two wires at each end of the tube itself , are for preheating , but no one seems to use them both , except the original (120 v ) circuit , did use all four wires separately..

i got this circuit off the net , looking at it , everything to the left of the IRF540 could be replaced with a pwm circuit/chip? i think

[Flux]

Driving fluorescents efficiently and with long tube life is quite difficult.

Producing light is fairly easy if you don't measure efficiency and don't count tube life.

Probably the best route is to make a simple dc to ac square wave inverter to produce about 300v ac peak and use normal 230v cfl. They rectify the voltage internally to about 320v dc.

I suspect the 110v units may have a voltage doubler so you may need 120v ac square wave to feed them. Or you could use 300v and rectify it and feed to the unit after the doubler but that means going inside it.

Circuits that don't use the heaters always damage the cathodes and end up with black ends on the tube if you start them very often.

Single ended drivers are not very efficient and are generally not good for long tube life, some of the cheap units are only suited to up to about 8W where efficiency is not important as they give little light and are only suitable for background lighting.

If you just want light with simplicity and low cost and not bothered with efficiency there are several push/pull square wave self driven inverters about that will cold strike tubes from the spikes during switching then run with the leakage reactance of the ferrite rod transformer. they often will work with tubes with damaged heaters that no longer run on proper ballasts.

I have seen the circuit in a few places, maybe B T Humble, but someone here, has adapted it for 3rd world use.

If you use this , don't measure efficiency with a photometer, the eye is not a good comparator of light output.

Flux

[nothing to lose]

Neat I never saw one opened, don't know why I never took apart a junk one myself?

Looks easy to work on. Gives me a couple ideas.

If using a good expensive 12V type and it burns out or goes dim, perhaps buy a cheap 120V, swap the bulb onto the 12V guts. Rebuild the $20 one for $2 maybe?

When you drop and break one, save it incase you ruin the driver in one later. Wish I had though of that before. Kid dropped an expensive 120V one and it broke the bulb of course, concrete does that. I had one I used outdoors that got rained on a bunch, it only glows one tiny spot now but won't light. Can't see how rain would ruin a bulb so it must be the circuit board right. Looks easy enough to swap parts on the $15 worth of junk and get a working $7 bulb again, to bad the wife tossed the droped one.

I do still have the rained on one, also a couple of those 12V tube type drop lights like for working on cars, camping etc..  Normally get those cheap at BIG LOTS in USA, about $3 last I bought one. Same thing at Walmart for about $10.

Time to canabalize lights, thanks willib for todays project, time to see what happens

[willib]

I used a dremmel with an abrasive  wheel attachment to get the  120V one apart , i cut it along the joint between the top and bottom halves, you can see where i cut it , in the pics.

[dinges]

Thanks Willib.

I've seen a lot of schematics, none that I like. This one could be ok, at least I've got plenty of old transformers from Philips TV PSU lying about...

You happen to remember where you find it? I'd be curious as to the maximum rating of this 'power' driver, and perhaps some pictures that go along with it. Esp. for the correct transformers.

Was thinking 'why quadfilar wound?', since they seem to use no taps, but it's probably done to reduce resistance of the primary without resorting to thick wire. I.e. 4 parallel windings.

I think I could build even such a complicated design in the foot of a CFL. Few SMD parts perhaps, creative layouting. Perhaps even add a 2nd level board.

It's still broiling in the back of my mind...

[nothing to lose]

You have great pics, can you get one of the circuit board for the 12V? All I can do is try to scan one, probably won't be very good. Only 7 parts on both of mine, transformer couple resistors, a cap, and I think a gate.  About 20 various parts some strange on the 120V boards.

I took apart 2 12V CFL drop lights after reading your post. A couple things I found out myself.

The power going to the CFL can bite you, I wanted to be sure so I tried like 3 times and it does bite a bit! My drop lights had problems. One had a loose gate? I had to hold it bent in place to get it to work, bumped a wire on the bulb and got bit.

If you connect one wire to the bulb and just hold the other wire near the bulb will glow nice and the Gate gets very hot, found out when a wire fell off. Could be why the first drop light stopped working.

The 120V light that had been in the rain and only glowed a little in one spot, glows well, but it is a 4 U tube type for about 100watts output. 4 Pins, looks like 2 pins for 2 U tubes each. It presses/plugs into the 120V circuit board. Glows enough I can tell the tubes still work, but does not really light useable. Wondering why the 120V board does not work, I figured corrosion etc.. but it's clean and looks fine.

The 26Watt bulb (rated) looks the same as the one in your picture as far as I can tell, almost exact same. Wife was happy I finally put a second bulb in the kitchen, Hmmm well she is back to one now

I popped it apart. Nice these thing aren't hard to get apart. Simply force a flat screwdriver down into the seam on the sides and pry it up. Top and bottom just snap together, pry apart.

I saw the 4 pins sticking up, with my eyes I thought it was heavy wire soldered to holes in the board. After about 30 minutes or more of looking for the soldering iron I found I did not need it. Close look and the thin stiff copper wire is only wrapped around the 4 pins, no real connection just wrapped tight. Find end with finger nail and untwist it.

To get the CFL drop lights apart I just cut the rubber end near the cord, peeled it open and pulled it off. Everything slides out of the clear tub easy. One of these is an older light maybe $10 from K-mart years ago, the other a $3 Big Lots light. Don't know which is which. Basically the same thing inside, but one is better made, same tube.

One drop light has a reflective paper backing and the circuit board is just there stuck inside.

The other has a metal reflector sleeve the full length and the thing I reffer to as a gate is screwed to it for a bit of a heat sink.

 Otherwise the 2 are the same far as I can tell by looking. I will buy the $3 ones from now on to be sure!! If modding it I can add a heat sink myself, alot better one than thin metal.

As far as light and power?

The drop light was 8 watt it claims, used 2amps @ 12V so 24watts.

The 120V CFL says 26 watts, used 2.7A up to 3amps, seemed something caused it to gain .3 amps as it warmed up. So 3amps at 12V, 36watts.

As far as light output with mine sofar, the 26watt was far less bright on the 12V board than when on the 120V board. It may be more light than the 8watt tube produced though. Hard to tell durring the day, but I like the twisty 120V tube better.

Now that I found my solder iron I will fix the gate thing, make permanant connection and test some more. Also I used a bank of 3 17amp SLA batteries. I found one of my 115amps gell cells needed charging and I am doing that now, will use it tonight. Maybe put the works outside for a yard light and see what happens if it don't rain tonight.

[nothing to lose]

I hadn't seen this post about cutting it when I posted the other,

Both mine I was able to just snap apart by forcing the flat blade screwdiver into the seam about where you cut yours. I may have damaged the spot a bit, but later I can snap it back togehter fine if I want to use it at 120V again.

[dinges]

Willib,

I've just taken apart a new 1$ Chinese CFL, and connected it to the FL driver from an old scanner. The circuit is meant for 12V and draws .55A, so input is about 6W; output is unknown, but it lights up a 11W CFL perfectly, as you can see in these pictures.

I doubt I get the full 11W of light though, maybe 5W, but still. The pcb is small enough to fit into the base of the CFL too...

These PCBs can be found in all old flatbed scanners, they usually drive the long & thin FL light in them. I've got several of these FL drivers lying about, and I know what I'll be looking for in my next dumpster-diving adventures: scanners.

The question of course is how long the thing will work; whether the CFL is perhaps damaged by the driver, etc. Of the 4 wires of the CFL bulb, I've only used two. No preheating of the electrodes was done. Also, I assume such scanner FL drivers aren't meant for continuous duty. Only one way to find out, I suppose.

[willib]

i just happen to have a flatbed scanner ( dumpster diving lol) i'll look insde ! thanks!!

[willib]

"can you get one(photo) of the circuit board for the 12V? "

sure !

[willib]

Wow good call Peter , besides the 12V fluro inverter ( pics 2 & 3 ), there is also a nice ground shaft with bushings .

and a optical switch (infrared), which tells the scanner when the bulb unit has returned to the home position , although i allready have a bunch one more is good too.

NTL your photo is coming

My gawd is it windy , Ernesto shoud arrive later on tonight

[willib]

That Mity Mite portable battery/jump start  is one of the best things i ever bought

its got the socket on the left for 12V out , a set of jumper cables , and a plug to go into an extention chord on the right ( a charger built in)

I left the scanner bulb in ,its pretty brite on its own

if the power goes out tonight , i plan on being the only one on the block with light

and of course i'm going to put one in the window.. lol

[willib]

Peter this is too funny .

look at that light ! lol

the lights are flickering , i sort of hope they go out

[willib]

i should have said the power is flickering.

check this storm out

http://www.weather.gov/sat_loop.php?image=wv&hours=12

if you have java activated on your machine ,the storm is at the upper right

[dinges]

Good fun eh?

Took me a while to find this link again, but here it is. Too bad it's in German:

http://www.b-kainka.de/bastel6.htm

http://www.b-kainka.de/bastel37.htm

It's a very interesting site IMO.

http://www.b-kainka.de/bastel0.htm

There's other ways too light CFLs too, BTW...:

http://www.b-kainka.de/bastel102.htm

[fungus]

Inside the scanner I took apart I found a long belt with a stepper motor attached and when I pulled the belt very hard I got 80v AC at 18w.

[willib]

i'm not up on my tubes , but the one in the last link is a switch , for sure , pretty cool stuff

oh the power never went out for us last night

but it is still windy as heck  , outside

ps in a few days you will maybe get to enjoy our storm too, as that is the way they go after they leave our shores, have fun !

[kitno455]

you got off easy, here in central VA, lost power for 12+ hours.

what about laptop screens? they have some sort of tube, and i have a BUNCH of old laptops at work. i also have a bunch of scanners, but not going to tear into working equipment

watch out, alot of scanner tubes have a fair bit of mercury in them. most new equipment has warning lables all over it.

allan

[stephent]

Most of the late versions of flourscent tubes are now directly fired and no longer use the "heater" circuits. The new electronic ballasts now just fire the tube with close to 600volts and then the voltage/currant sags to the operating point.

Question for Flux----how does directly firing the tube make the end blacker then using a "heater"/cathode circuit?

[willib]

As requested , the circuit board from the 12V board.

recap: this board is a standard T5 driver/inverter, whatever, which runs off of 12Vdc and powers a T5 fluro tube

this is a bit beefier than the scanner board inverter/driver , the transformer is larger , it has one power transistor w/heatsink , about 12 parts total , if i recall correctly (IIRC).

where the scanner board is smaller , it uses two TO92 size tranistors , but after it is on a while it only consumes .216 A , not bad !





i will post a "comparison" in a few mins.

[willib]

the light on the left is a "lamp" i made from a one dollar $1 cfl , powered by a scanner tube ciruit and running off of 12V, power consumption is 2.6W

the light on the right is the same tube ,but is origional and powered by 120v rated at 20W

the only way to tell the difference between the two lights (in a picture) is the shadow produced by the origional 120V one , on the right

granted when i'm working at my bench i prefer the 20W (120V) light , but the scannerboard light will provide enough light to illuminate a room, and at 2.6W it makes an inexpensive nightlight,or with a reflector behind it ,a night reading light

[Flux]

There are cold cathode CF tubes available that don't have heaters and these are used for scanners and backlighting for LCDs etc. These have special cathodes and it may be that to cut cost some CFL manufacturers are using these.

All the units I have taken to bits use the heaters and driver circuits from IR and Texas etc use chips that pre heat the heaters before applying striking volts.

Many years ago some cold cathode standard size Fluoro tubes were made but they soon disappeared.

For proper operation there has to be electron emission from both cathodes, once started the heat of the discharge is enough to maintain the heaters at operating temperature.

Without heating conventional tubes will only strike if there is sufficient voltage to cause sputtering of the cathode areas and this causes cathode damage. The number of starts is reduced but may still be acceptable. More of a problem is the tendency of these cold strike methods to only cause a unidirectional discharge and once started in this mode, most oscillators will run indefinitely this way. This results in a blackening of one end as ions migrate one way. With a bit of luck starting will be random and eventually both ends blacken.

The smaller the tube the less the problem so it may be reasonably acceptable to cold strike small tubes of a few watt rating even if they have heaters.

Cold striking does give higher circuit efficiency as the heater resistance causes losses in the resonant ballast circuit.

I have noticed a lot of difference in the various commercial CFls so there may be a variation in the methods of operation. Some of the cheap imports obviously use something dreadful, I have had some last only a few months. I have some Philips units that have been running for about 15 years.

Most of my experience with drivers has been with conventional fluorescents and I have never had any luck with cold striking them.

Flux

[stephent]

Find a local PC modding geek and see if they have a few driver boards for the CCFL's they usually install and then remove for another color.

Scanner tubes usually are driven a bit "hot" and aren't usually full time rated (inverter stuff) making a bit of heat when used full time.

http://www.xpcgear.com/lightingmods.html

New stuff isn't too bad a price these days--but I would say "recycling"/"reusing for another purpose" this stuff would be cheaper. Watch carefully for some of the Neon type lamps/inverters used for cars or PC's--they use a much higher output voltage then the CCFL's or even the LED types available too.

Maxim makes a bunch of these type drivers and if registered with them--they even furnish samples (free) in small lots, 2 usually limit of each. And send you a monthly little magizine that describes some of their wares available and uses too.

The One-Wire (Dallas Semi) branch of Maxim makes some neat sensors for remote monitoring of everything from weather (temp--etc) to you name it.

Google "aag" for a cheap(er) one (weather monitor) that works well.

But the CCFL tubes are certainly rated for long life--11K to 15K+ hours.

Looks like a good usable source of cheaply obtained "light" to me.

And reuse/recycle/use up is right down my alley.

Not to mention the several old scanners laying around here just waiting for "reuse" purposes.

Nice pics willib, good detail--thanks.

[nothing to lose]

" Also, I assume such scanner FL drivers aren't meant for continuous duty"

Not sure abot the old ones since the tubes only lit when you really wanted to scan something, but some of the newer scaners with all those crappy buttons for e-mail, etc... want to run the light anytime the computer is turned on, 24/7

Thats is something that has always ticked me off with a scanner here, if I have the power connected and computer on the tube will be on. Never mind maybe I have not scanned anything in a month and don't want to, the light comes on and stays on if the computer is booted. I think it does not shut off the light even when the computer is off, and that is why I have it on a switch to shut off power to it!

[nothing to lose]

One of my meters is whacked.

One reads 3amps, the other reads .3amps.

"The drop light was 8 watt it claims, used 2amps @ 12V so 24watts.

The 120V CFL says 26 watts, used 2.7A up to 3amps, seemed something caused it to gain .3 amps as it warmed up. So 3amps at 12V, 36watts."

Well,

8 watt tube may only be using .2 amps @ 12V so 2.4watts??

The 120V CFL says 26watts, could be .3 amps on the 12V board for 3.6 watts??? Not as bright as when used on the 120V board but not as hot either.

I laid mine on some white carpet for a short time, as the tempature of the light warmed it got brighter and also used more power.

I laid the light on a metal drill box an as it cooled again the light got a bit dimmer and power use went down.

I'll have to figure out the meter and the problem, but I went from 3-9amps or .3-.9 amps depending which meter is right. At first I thought I used a wrong setting, but I just used both meters on the same setting and they are off by X 10  compare to each other

[dinges]

Willib,

I've just found another use for scanner parts...

Know the little lense that is inside them? I've used one as an add-on macro lense for my digital camera (without a macro-option). Now I can do REAL close-ups:

http://www.anotherpower.com/gallery/dinges?page=4

Them scanners is regular goldmines indeed

[NT]

I read the discussoin of running CFLs on scanner invertors, but am aware that the scanners I've opened have all had CCFL tubes, which are a different animal to CFLs. CFLs have electrodes inside, whereas CCFL have no electrodes in them, the power is applied through the glass wall capacitively.

Running a CFL on a CCFL invertor effectively means youre shorting out the glass capacitance, and your invertor may overheat.

Also running CFLs, or any electroded fl tube, at much below rated power will cause rapid electrode damage and thus short life. Sure it can be done, but there is a much better way. Instead of applying the power to the elctrodes, stick foil on the glass with same area as the ccfl had, and connect up to those. Now your tube is correct load for the invertor, AND youre running it without using the electrodes. This means not only do you get no loss of life, but your tube should last a lot longer than its original as new rating. AND you can use tubes that act dead on ordinary cfl ballasts, and gets long long life out of them.

NT

[dinges]

Thanks NT, I didn't know that CCFLs were capacitively powered. My inverters don't overheat after a few hours of continuous testing. But, I was already afraid there would be a snag, it was just too easy & good to be true.

I've heard about the method of an external electrode before, but IMHO it's getting close to the area of 'kludging'.

BTW, I checked out your other responses. I've noticed your accurate phrasing and use of the correct terms... You've worked in the lighting industry?

Anyway, welcome to the board!

[NT]

I'm wondering why you see it as kludging, as you get a much better end result in terms of life expectancy aka reliability. One significant downside is the high voltage on the surface of the glass can bite hard, so it needs a protective cover.

Thanks for the welcome - I've not worked in lighting ind itself, but in electronic design.

NT