Using Dimmable Ballasts.

[NAKEDGARDENER]

I know this is another noob question but I was wondering how people use the settings on their dimmable ballasts.
Is there any good reason to have a schedule throughout the 12 hours of light where when lights come on the ballast is say at min output such as 50% then increasing the output so that during mid cycle, the lamp is on max or “super lumen” for a few hours, then retarding output down toward end of daylight cycle?

Or is it best to just have the light output set at one level? Does manipulating the different outputs as I mention above, effect or shorten the hps bulbs life and output.?

Thanks in advance for your thoughts.

[Chefbjy]

Yes it will shorten the life of hps. The idea is to get as much light energy stored into the leaves like the sun would. Dimming would be useful for heat but keeping it set to full would be ideal. Leds are different with dimmers but dimming an hps won't benefit any other way imo.

[NAKEDGARDENER]

Thanks chef, this was my thinking also, and I have it set to 100% and was gonna use the next point up which they call super lumen, during last few weeks of budding.

[kingfish]

I have never figured out the logic behind dimmable ballasts. If I go out and buy a 1000w ballast and light, then why turn it down to 50% ? I want all the wattage I can get.

[NAKEDGARDENER]

Yeh I see that point. This is my first dimmable digital ballast I’ve used. Last one was a huge heavy. Hunky thing years ago. I wasn’t gonna use an hps but my plants needed more light so I bought this one from a friend locally. As it happens I’ve been leaving it set at 100% and not using its max setting due to heat control

[DrPhoton]

The dimming function would be handy for using different flux levels for different stages of growth. Simply running lights at full power with not much horizontal coverage by plants, is a waste of energy. However, the dimming functions are completely useless for metal halide, as they lower the bulbs efficiency and wavelengths in the blue spectrum. So at all times it should be avoided with metal halide. However, they can be used for sodium discharge, but the bulb must never be reduced by more than 50%. But again this becomes useless as by the time you require your sodium discharge, you will want to have it on full for the flowering stage.

As such, the only option for making the most of light, is by using lower wattage bulbs with compatable ballasts.

See my article on using light efficiently.

[DrPhoton]

Sounds good, the more you refine the better it will get. Its so much fun isnt it ^.^

[NAKEDGARDENER]

DrPhoton yes Sir it is, and with thanks to you and all your intuitive and learned advice, has made it even more fun... I’m hungry to learn much more...

[Ell]

good comment for me as i run a 1K at 600. needed the 10 degrees cooler in my 4 by 8 room. thanks

[Euroaznscotty]

As its been said the only thing I use my dimming for is to reduce the heat. Mine is 1000W dims to 750, 600 & 500. Most places that you buy your HPS light (as long as you're buying high quality) offer the 1 year warranty which includes your bulb dying because of dimming.

its all really personal preference and what your grow space can accommodate (heat wise)

[NAKEDGARDENER]

Inside this tent 4x4x7 heat is manageable and steady at 80 f with lamp on super, other lamp is hot but no way near as hot as the hps obviously. So far so good and no inline ducting fans being used, new replacements arrive sometime next week.

[Euroaznscotty]

That's really nice temp. Unfortunately my tent sits closer to 90f. 2x2x7. There are times when its hot in the room that I have to dun to 75% to drop the temp bigger grow tent next time

[NAKEDGARDENER]

Or you may consider a smaller light for that size tent, even the 4x4 is too small for my liking, I don’t like the restrictions, so have decided to make the room that this tent is in, into a grow room, line it, and large vent system, probably 12 inch x2 for exhaust and intake to outside. The tent I will use as a doorway sealed entrance to room itself, then when growing in early stages next time use as early veg room.

[Euroaznscotty]

I just have the 2x2 for the time being. I will be moving in the next couple years and we are having a greenhouse built. So that will be my new grow area

[NAKEDGARDENER]

Well maybe something like an LED full spectrum might work for ya, I’ve been looking at a 1k light by KING LED and at $115 us. I’ll give one a shot.

[NAKEDGARDENER]

And yeh I bet ya can’t wait for that..