Lamp Lumen Loss Over Time

[Quazi]

Hello everyone!

Was doing some research today about when to replace my HPS lamp when I came across a really nice chart from the National Lighting Bureau. Thought it might be handy!

Hope it helps others get a general feeling for how quick their lumens decrease as they use their different types of lamps:

-Q

 

[White]

Thanks man,
I was just wondering about this the other day.

Peace,
White

 

[Guest]

Fantastic! Thanks a lot. I've been wondering about this, as a novice, a sheet like that is invaluable.

Also, your cabinet report has been a great resource and source of inspiration, thanks for that even more!

Peace,
A

 

[samba]

Did I understand correctly?
It would take 24.000 hours for a HPS to drop to 70%?
That would be over 5 years on 12/12!
I've heard you should change your bulb every 2-3 grows,thats (2months*3grows*31days*12hours)=2232hours, assuming you don't veg with it.
Thats less than 3%

 

[Quazi]

Thousands of hours along the bottom there :wink:

Twenty-four thousand hours to reach 70%.

-Q

 

[BlindDate]

Yeah.....even 80% is 4 years. Maybe these guys are using regular warehouse bulbs and not our $120 super turbo-charged grow bomb lights.

I think each brand/model bulb has to be charted by itself.

"The star that burns half as long burns twice as bright"

 

[Gunnarguchi]

Hello everyone!

Was doing some research today about when to replace my HPS lamp when I came across a really nice chart from the National Lighting Bureau. Thought it might be handy!

Hope it helps others get a general feeling for how quick their lumens decrease as they use their different types of lamps:

-Q

thats very valuable information
if just a 10% loss is a guideline the metal halide still lasts apr 4000 hours and the hps last 10000 hours

 

[Gunnarguchi]

Hello everyone!

Was doing some research today about when to replace my HPS lamp when I came across a really nice chart from the National Lighting Bureau. Thought it might be handy!

Hope it helps others get a general feeling for how quick their lumens decrease as they use their different types of lamps:

-Q

thats very valuable information
if just a 10% loss is a guideline for replacement the metal halide still lasts apr 4000 hours and the hps last 10000 hours

4000 hours with 18/6 thats 222 days for the metal halide
10000 hours with 12/12 thats 833 days for the hps

i actually thought it lost its value much quicker

 

[Gunnarguchi]

btw this one should be sticky

 

[Quazi]

Whether this is referring specifically to a type of lamp wasn't why I posted it.

I was tired of seeing charts given to me by websites that try to sell lamps to me. The data that I was getting from science wasn't matching up with some of their claims.

I wanted to see some information from a nationally accredited organization.

That's why I posted it.

Take it for what you will :wink:

-Q

 

[White]

Quazi,
Have you come across anything for Ceramic Metal Halide (CMH) ?

 

[Quazi]

I haven't.

Though: I would divert any questions about CMH to the thread dedicated to it.

http://www.icmag.com/ic/showthread.php?t=72215

-Q

 

[BlindDate]

If that chart is correct, then I threw away a shitload of perfectly good bulbs over the years.

I have a light meter and have tried to measure bulb output over time, but it is very difficult. The slightest variation will change readings. If the light probe is not pointed exactly straight, or the bulb is slightly tipped, or something reflective in the room changes, etc.

The only way to answer this question is to build a test fixture with a mounted light meter and plot the decay over time ourselves.

My next project.

 

[OldMan&theWeed]

1 year = 8766 hours. That's 4353 hours of 12/12 in a year.

Therefore if a 10% loss is a guideline for replacement of a HPS, a HPS bulb should last close to three years!

 

[junior_grower]

wow good to see.

 

[bongeyser]

looks like we need to switch to low pressure sodium the line just ends at 18 though no drop off at all does that mean it's no good at all after?

 

[Gunnarguchi]

i just bought a light meter on ebay and i look forward to do some measuring in the future

i bought 10 used 400 Phillips lamps with spare bulbs
might do some testing to see if any of the bulbs are still good to use
also the measuring will be able to determine if any of the ballasts inside the GH lamps are too worn out to use

 

[asde]

that chart looks like its 20 years old..
if you really want to know the lumen maintenance go to the philips catalog (for philips bulbs ofc) and watch the product pdf files instead or your the one to spread false informations another day - dont be the stupid guy.

 

[Hydro-Soil]

If that chart is correct, then I threw away a shitload of perfectly good bulbs over the years.

No you didn't.

What this chart fails to show is the loss of 'Useable' light that the plant can grow with. Though the 'Lumens' may take a really long time to drop, the actual production ability of the lamp is long gone by then.


Keep changing your lamps, if you don't want to lose yield. Lumens is really a crappy measurement for growing.

 

[sparkjumper]

I was wondering the same thing.Your par watts may decline much faster than lumens in which case it means nothing.I'll do 4 or 5 grows before changing hortilux lamps but no more than that.