Dimmable Ballasts

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..

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.

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 interesting

Keep in mind, the two reflectors are different types and what I'm calling the canopy level is just where I measured at for each reflector and those distances for each separate reflector are different.

At some point I'd like to do a more controlled test all with the same reflector.
 
yeaaaaah. theres a reason why they make 400 watt ballasts with 400 watt bulbs.

better lumens, bigger plants this round...next round your house is up in flames.
im good.

i run my 1000 watt thunder dim able ballast at 50%-500 watts.
although i have different settings
50%-500w
75%-750
100%-1000
SL 115%-1150
...but my question is am i going to hurt anything if for the final 3-4 weeks flowering i turn it up to 115%...will it give me significantly more lumens thus creating more bud?
 
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..

only time i hear it is when i run a non E-bulb on an e-ballast.
doesnt really answer the question, but maybe that info will help you come to some kind of conclusion.
 
my question is am i going to hurt anything if for the final 3-4 weeks flowering i turn it up to 115%...will it give me significantly more lumens thus creating more bud?

I want to know the answer to this too. :lol: I just built my set up in the last month with a new ballast that's dimmable, and I only turned it down today to solve a temperature problem (I just launched my flowering room last weekend, still tweaking it). I also still have fans on order and I will add another intake to increase air flow and get the temp down. I want to flower at 100% otherwise its pointless to use a 1000W light. Right?
 
My environmental controller has a sensor with a built-in light meter. I have Phantom 1000w dimmable ballasts. From what I've noticed using HPS, the 75% setting is just about exactly 75% of the 100% setting. However, the 60% setting is only about 40% of the 100% setting. Also with MH/HPS bulbs, I do lose a noticeable amount of blue spectrum at 60%, but not that much at 75%. So basically, I avoid the 60% setting and just use 75% and 100%.

Phantom ballasts rock!! I have a 600 and I'm waiting on my 1k. Can't wait.
 
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.
i can tell you for sure superlumens will cut your bulb life by at least 30 percent. it is good to get a bit more out of an old bulb . i am also finding that some of the cheaper bulbs are as good as anything. peace out
 
I am planning to run a 600 w ipower ballast dimmed 50%. It should draw around half the usual amperage no? I have a very limited circuit and I want to make sure it's safe as possible.
 
I can say Ive been running both my cheap ipower digi ballast with horti bulbs at 50% for almost a year now with great results. In my 5x5 tent 2 six's at 1200 was to much and two 400's at 800 was not enough. I chose this configuration and ballast for its 50% over 60% from the get go to get exactly 50 watts psf. Works for me!
 
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