Hid lights. cycling frequency?

[larry_g]

I was given 3, 400watt HID light fixtures. I replaced one of my flourosent fixtures with it and I am impressed with it, lots of good light. My question is should I be cycling this light on and off 3-4 times a day as I go in and out of the shop or should it be only used for long term projects. Asked another way, does this lamp die faster with on/off cycles?

lg
no neat sig line

 

[Charles (in GA)]

That is an issue with not only HID but fluorescent lights also. If you want the published bulb life from them, they expect you to start them and leave them on. The bulb life is based on something like 12 hr run time between starts. T5 fluorescent bulbs have a published life of about 35,000 hrs with 12 hr run time, and 20,000 hrs with a 3 hr run time. HID is similar.

Yes, you do shorten bulb life (and the ballast start capacitor life) by frequent cycling of the lamp.

Charles

 

[larry_g]

Thanks Charles, I was suspecting that but it does not sound any more harmful that any other fixture.

lg
no neat sig line

 

[nehog]

Personally, I think it depends on factors like: "Do you need the light on quickly, or can you wait" and "How long will you be using the lights?"

I use my HID lights infrequently (I have both HID and florescent) but when I turn them on I usually turn them off if I think I'll be away for awhile. If I'm coming back in after only half an hour, I'll leave them on, after all it takes four or five minutes for them to warm up.

I don't consider life span important--it will take me several of my lifetimes to get to that 20K hour of usage time!