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-   -   Fluorescent lights don't seem to last (http://www.diychatroom.com/f18/fluorescent-lights-dont-seem-last-129421/)

preciouschristy 01-09-2012 05:28 PM

Fluorescent lights don't seem to last
 
I installed some inexpensive fluorescent light fixtures in my garage some months ago, and bought a 10-pack of T8 tubes. Less than a year later, all of the bulbs have gone dim.

The fixtures are Lithonia $20 wrap-around 2-bulb fixtures
The bulbs are Philips 32w T8 4-ft bulbs

If I replace the bulbs, the new bulbs work just fine. What I'd like to know, though, is why did they burn out so fast? Is it more likely a problem with the fixtures or the bulbs? Or is it normal for fluorescent tubes to burn out that fast? They are in the garage, so they don't get a lot of continuous use (ie. they're turned on and off a lot). Before I start replacing all the fixtures, I thought I should try to get some input from the chatroom.

Thanks

TarheelTerp 01-09-2012 05:41 PM

Quote:

Originally Posted by preciouschristy (Post 817760)
is it normal for fluorescent tubes to burn out that fast?
...(ie. they're turned on and off a lot).

how many of these on/off cycles per day?

dmxtothemax 01-09-2012 05:56 PM

I have always been told that floros dont like being switched on and off
frequently!
Instead they are ideally suited for applications were they are on
for extended periods, or continually.
Rather then frequent on off cycles.

So this could have something to do with there short life !
other things like cold weather can play a part also.

Even high voltage can shorten life,
but it would have to be significant,
a small increase would not be signiicant for a floro.
as it would for an incandesant.

preciouschristy 01-09-2012 06:36 PM

Typical garage use- the laundry is in the garage, as well as our yard tools, so probably several times a week. I don't like leaving the lights on when I'm not in the room, but do you think that would alleviate the problem? Even if I changed the fixtures to regular socket-type fixtures, the future seems to be forcing everyone to go CFL anyway, so I'm not sure that would help things.

gregzoll 01-09-2012 06:43 PM

CFL's are nothing but florescent bulbs, with a built in ballast. Nothing new to the technology. As for the tube bulbs going out, where are you getting them? I usually will buy a case pack when they are on sale, and mark the bad tubes when I place them in the box, after I take a good one out. Once full, take to a disposal center to get rid of.

I have not had to replace bulbs in over a year, possibly due to went out and bough some good bulbs at the local Menard's, due to cheap ones from the Lowe's.

AllanJ 01-09-2012 07:40 PM

I am guessing that turning on and off twice a day on average should not result in a "short" life. Except that I am led to believe that each turn on in low temperature puts more wear and tear on the fluorescent tubes the lower the temperature goes.

To get the fluorescent lamp started, electricity has to jump the length of the tube. The electrodes at each end are coated with a material that makes it easier to make the jump, but the material deterioriates a little with each start.

preciouschristy 01-09-2012 07:59 PM

So it sounds like it's because I bought cheap bulbs? The tubes were about $25 for a 10-pack. I'll look around and see if I can find better tubes than the Philips.

gregzoll 01-09-2012 08:17 PM

I only use Sylvania bulbs. $2.50 a bulb is pretty cheap. And yes, you can get a bad batch of bulbs, and depending on the fixture, the ballasts can also be culprit in why the bulbs are going out so quickly.

Missouri Bound 01-09-2012 08:21 PM

Can you open a fixture and tell us what the ballast say? It's very possible you are using the wrong bulbs. Most of those cheap fixtures use T 12 lamps.

Ironlight 01-09-2012 08:28 PM

I'm going to posit that if you've gone through a whole carton of tubes in less than a year that your problem is not crappy tubes, but either the ballasts or your electrical system.

The bulbs should last longer than that. If these are the Lithonia T8 8' of 4' units, I can state with some confidence that they have pretty lousy ballasts in them. That's how they are able to sell the lights for $19 a pop, as the ballast is 98% of the manufacturing cost of these things.

I would try replacing the ballast in one of the units with a quality ballast and see how things far with that unit against the others. Time will let you know if you've found your culprit.

preciouschristy 01-09-2012 08:34 PM

I'm using the right size bulb-

I was thinking that- is it actually worth changing the ballast? Or should I change out the whole fixture. Admittedly, I'm not looking forward to changing out the fixtures, they weren't a lot of fun to install in the first place, but it doesn't seem like changing the ballast would be much easier.

Missouri Bound 01-09-2012 08:40 PM

Quote:

Originally Posted by preciouschristy (Post 817965)
I'm using the right size bulb-

I was thinking that- is it actually worth changing the ballast? Or should I change out the whole fixture. Admittedly, I'm not looking forward to changing out the fixtures, they weren't a lot of fun to install in the first place, but it doesn't seem like changing the ballast would be much easier.

Did that fixture come with bulbs? Tell me how you know it's the correct bulb.

preciouschristy 01-09-2012 08:44 PM

Well, the box and installation instructions said it took T8s, and it doesn't look to me like T12's would fit anyway (it's a skinny fixture). The ballast is pretty inaccessible, so I don't really want to disassemble the whole fixture to get to it, if I don't have to.

I realize that there's a possibility that they put the wrong ballast in, but on three of them? Bought a few months apart? Seems unlikely.

Missouri Bound 01-09-2012 09:08 PM

OK. The bulbs are correct. There are a few things that shorten bulb life. Most often it's the bulb improperly installed; not twisted in properly. Another thing that creates problems is a poor ground. Since your fixtures are fairly new I doubt the tombstones are bad. Improper voltage is a concern, but not usually an issue. Bulb life is greatly reduced by excessive cycling. (off / on / off / on). And as already mentioned the fixture uses an inexpensive ballast. T-8 lamps have a life expectancy of 20,000 to 30,000 hours. Cheap fixtures are probably the culprit since it's on all fixtures.

Julius793 01-10-2012 12:28 AM

The problem is HD :laughing:


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