Thread: how long is a piece of string??

I would be upset if I only got 9000 hours on some of mine.
They run 24/7 and I get 3+ years out of them.

Turning them on and off causes deterioration of the tube.

Hi,
You do not say what size tube. A four footer lasts a lot longer than a two footer or fifteen inch one.
Regards

Originally Posted by Grumpy John

**********Whinge alert**********

Nothing to do with string, but has anyone ever managed to get the 9000 hours out of a flouro tube as stated on the box. I'm lucky to get 6 months out of the tube in the kitchen. Allowing for the tube to be running an average 8hrs/day that's just under 3000hrs/year. Fair enough the stated life is "UP TO 9000" hours, but I'm lucky to be getting 1/4 that.

i have a circular (about) 15" diameter tube in the kitchen which i would use about 2 to 3 hours each day .... it has been going for 14 years last may ... seems fine

i also have compact fluoro bulbs that do a lot more work than that .... i have replaced three out of about 20 of those in the last ten years

regards david

I've taken to writing the date I put the globe in on the base. They really don't seem to last as long as the box says. Curiously none have "blown" since I did that.

The fluoro light in our kitchen is never turned off. It's been going for about 52,000 hrs so far and it was in there when we moved in.
I have a few compact fluoros around the house and they are rubbish. Very variable in quality. I've been slowly replacing them with LED globes.
I forget what life the LEDs claim but I had one fail after a couple of months. Well short of the stated life. I sent an email to Philips and they replaced it no problem.

Originally Posted by A Duke

Hi,
You do not say what size tube. A four footer lasts a lot longer than a two footer or fifteen inch one.
Regards

The light fitting has 2 flouro's a 32 watter and a 40 watter. From memory the smaller one does get replaced more often, but neither gets anywhere near 9000 hours. I always fit new starters when replacing a tube.

As has been stated before - quality of tubes/bulbs is highly variable.

I think you have said the key words relating to the length of time "Up to".

As to your original question regarding the length of string, easy,

"twice the distance from one end to the middle".

Just fitted 2 new flouro's in the kitchen 1 x 32 Watt NEC Quad Phos and 1 x 40 Watt NEC Quad Phos with new starters. I have written the date on the tubes and am keeping the receipt. All up $47.80 for the tubes and $1.50 for the starters.

You may get better results if you fit both tubes with the same wattage. Can't remember where I read it, but I think different values can affect tube life if the tubes are wired in series not parallel.

Originally Posted by bsrlee

You may get better results if you fit both tubes with the same wattage. Can't remember where I read it, but I think different values can affect tube life if the tubes are wired in series not parallel.

With fluro's you need to fit the correct one to match the ballast and/or fitting. A straight 4' tube use to be 40w but is now 36w, you would not be able to fit an 18w tube as it is only 2' long. (About half the length.)

I am pretty sure Grump John is fitting circular fluros in which case the 32w fits inside the 40w due to their different diameters.

If you have tubes working in series, one will not work without the other, then it is best to replace both tubes at the same time, very often two 18w straight fluros.

And here I was thinking that a 4-foot tube would last 2X as long as a 2-foot tube.

My house was built about 1975, I bought it in 2000. Judging by the grime, the pair of fluoro tubes over the K. sink had never been touched since the place was built. I washed them, put them back, still going strong.

Not long ago, we had a power failure and I had to go off the grid for 90 minutes.
My Pure Sine inverter has a rolling display which includes output watts load.
Incandescent "Trouble Light" was sucking 50 watts, that was OK.
Needed to run an 18W LED, bright as a 150 incandescent.
The inverter display showed an output load of ZERO!

Makes me think that I could leave the LED light on 24/7 and the solar panels would keep the system topped up.

Originally Posted by bsrlee

You may get better results if you fit both tubes with the same wattage. Can't remember where I read it, but I think different values can affect tube life if the tubes are wired in series not parallel.

There are two round flouro's in the fitting, one inside the other (see photo). Different size flouro, different wattage.


Pictures_0015.JPG

Originally Posted by Grumpy John

Just fitted 2 new flouro's in the kitchen 1 x 32 Watt NEC Quad Phos and 1 x 40 Watt NEC Quad Phos with new starters. I have written the date on the tubes and am keeping the receipt. All up $47.80 for the tubes and $1.50 for the starters.

The 32 Watt flouro died a couple of days ago, which means it lasted just under 12 months - way short of the *9000 hours stated on the box.





* Rated average life is 9000 hours when tested according to IEC/EN 60901 standard.
Actual life varies in individual circumstances.
Frequently switching ON & OFF of lamp reduces lamp life.

I think that the 9000 hours is in relation to if you left the light on all the time and did not switch it off it would last the 9000 hours.