Ive used the dimmable 1000 watt lumateks for a couple years and dimming doesnt seem to mess with the life of the bulbs. Ive done whole rounds at 750 in the summer,and i usually dim down to 750 for the last week or two of flowering sometimes. The guy at the hydro shop (yes I know probably full of shit) told me the thing that can run them down faster is when you run them at superlumens/1100 watt mode for long periods of time.
me on this one but do some simple observation tests. and if you have a light meter all the better.
Do you hear a high pitched sound when you under dim a lamp from it's rated wattage? I hear it, and it makes me think it's causing premature wear on the lamp.A common misconception is that you have to use the same wattage bulbs when dimming. People seem to think that if the ballast is dimmed to 600 that they need a 600w lamp. Not true. It even says on the instructions inside galaxy ballasts " A 1000 watt bulb can be turned down to 600, 400, or even super charged to 1100 watts." Nowhere is there any evidence that dimming your bulbs will shorten the life of them. running lower wattages on dimmable settings will not shorten the life of the ballast. They were engineered to work that way, by the manafacturer... In the summer, due to heat issues, I run my 1k hortilux bulbs at 600, and sometimes at 400. I change bulbs every year. Never ONCE had any blowouts... As far as the PAR goes and the spectrum of the bulb, when dimmed, I believe there are discrepencies there. Nothing serious enough to stop me from getting in a summer harvest...
It's not the ballast buzzing I'm talking about, it's the lamp. Something in there seems to be oscillating at an abnormal frequency. It only happens when I underwatt, but not when I over watt. I've actually been wanting to take some light readings at different dim levels, so maybe I'll do that soon..@ PJ. I have heard that buzz that you are talking about but it was due to a faulty ballast. I bought a brand new galaxy 1000W dimmable and when i got home and plugged it in, it worked just fine on the 1000 setting. As soon as i dialed it down, it started to buzz, and then it just stopped working. I took the ballast back to the store, they replaced it, and said that was not supposed to happen, and if it did, you got a faulty ballast.
@ retiredmatt : There is most definitely a noticeable difference in lumen output when dialed down. I can see it with my eyes. I dont have a light meter, though. It would be a great test and find out just how efficient the bulbs are when dialed down. I know that a 400W lamp, on a 400W ballast produces roughly 50,000 lumens(dependent on lamp brand). Anyone with a light meter?? It would be great to have a real answer..
blessings- PK
OK, I just ran some numbers for you. Prolly not exactly what you're looking for because I'm already running a mismatched lamp (250w) in my 400w dimmable ballast. Also, my 600 ballast isn't dimmable. I was gonna swap through a bunch of different bulbs and take photos and do an extensive test for you, but then I got lazy and remembered I have to trim a couple small plants tonight too, so anyway..There is most definitely a noticeable difference in lumen output when dialed down. I can see it with my eyes. I dont have a light meter, though. It would be a great test and find out just how efficient the bulbs are when dialed down. I know that a 400W lamp, on a 400W ballast produces roughly 50,000 lumens(dependent on lamp brand). Anyone with a light meter?? It would be great to have a real answer..
blessings- PK
So You're getting more foot candles at canopy level running a 250hps on the 400bally than you do off of the 600 watt bulb on reflector B? Thats wild. Kind of confuses me too... +rep for the test thats very interestingOK, I just ran some numbers for you. Prolly not exactly what you're looking for because I'm already running a mismatched lamp (250w) in my 400w dimmable ballast. Also, my 600 ballast isn't dimmable. I was gonna swap through a bunch of different bulbs and take photos and do an extensive test for you, but then I got lazy and remembered I have to trim a couple small plants tonight too, so anyway..
The tests were done using the following lamp/ballast combo -- the 400w is a dimmable revolt ballast with 50%, 75%, and 100% settings -- the 600w is a galaxy non-dim:
Reflector A:
400w ballast @ 75% setting w/250w HPS lamp (this is how I normally run my 32"x32" tent) = 6500 foot candles @ canopy level
400w ballast @ 50% setting w/250w HPS lamp = 5100 foot candles @ canopy level
400w ballast @ 100% setting w/250w HPS lamp (no, I'm not afraid to over-watt) = 8000 foot candles @ canopy level
Reflector B:
600w ballast w/600w HPS lamp = 9500 foot candles @ canopy level
400w ballast @ 100% w/600w HPS lamp = 6200 foot candles @ canopy level
400w ballast @ 75% w/600w HPS lamp = 4400 foot candles @ canopy level
Hope this helps.