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Dimmable CMH ballast : can I use it safely?

R

rastafari80

Hi,


I'm at the start of a new experience and I have a new cool cmh light.


I was wondering the best way to use it and I'm not sure if I should use the dimmable possibilities if my ballast.


Using a 50% power during weg, or 70%, should be very usefull... but will it ruin the bulb or affect its perfomance once you put it back on 100%?


I can't find any recommendation on the manual except the main rule to use the bulb at least for 10 minutes straight before any shot down or power change...

does anyone have any suggestion?
 
OG_NoMan

OG_NoMan

Not Veteran
420giveaway
There is no reason to dim a CMH. Buy the wattage you want either 315 w single ended CMH or 630 w double ended CMH. The ballast is CMH specific.
 
R

rastafari80

I don't think you get the question or maybe I don't understand your answer. lol.

Lumatek sells a cmh spcific dimmable ballast.
My question is: does it affect the bulb in some way?


HXXP://lumatek-lighting.com/2018/02/13/lumatek-315w-cmh-2/
 
OG_NoMan

OG_NoMan

Not Veteran
420giveaway
rastafari80 said:
I don't think you get the question or maybe I don't understand your answer. lol.

Lumatek sells a cmh spcific dimmable ballast.
My question is: does it affect the bulb in some way?


HXXP://lumatek-lighting.com/2018/02/13/lumatek-315w-cmh-2/
Click to expand...

You're right I dont get the question :biggrin: why would you want to dim it below 315 w? Probly just use cfl,led for less than 315 watts. I dont think the bulbs are meant to be dimmed as it will probably change the spectrum. This is all opinion of course, you could contact lumatek and Phillips (assuming this is the bulb you will use) to get their factory opinion :tiphat:
 
R

rastafari80

Thank you OG for your answer and support...
well... It takes over 10 days to have an answer from lumatek but they assured you can dim a 315w bulb without any problem in durability and potency.
Spectrum may vary, you right, I read something about it.


Why to dim a cmh? There are plenty of reasons to do it: saving waste of energy [when plant are too young], avoid heat [when you can't find any other solution], use just one light source since early veg stage are the three main reasons I guess... at least to me.
 
H

heatherlonglee

Active member
I believe what OP is asking is this. Should he run the bulb at 100% for the 1st ten hours of bulb life, then after can he dim and not hurt the bulb. Yes to both OP! Run the bulb at full power for the break in period; then run at whatever wattage (under the rated wattage) you want.

Honestly the directions on this are very tiny and not really all that noticeable; extremely vague!
OP Run the bulb full power for 10 hours, then party on!
 
R

rastafari80

@heatherlonglee: [who's OP?] Sure, I think you're right. I think caution is very important and running the bulb full power for 10 hours sounds very appropriate. That's why I won't use it immediately but I'll use a HM for my veg...
I think in my next cycle I'll use only the cmh, both for veg and flowering stage, dimmed for veg as needed.

I give you guys another [maybe useless] info: I discover that a 150watt CMH bulb has a different socket [not the pgz18 socket, I think it's called g12 socket or similar] SO you can't use it without some kind of adapter.
 
G

gh0stm0de

Active member
There is no reason not to dim your CMH lamp if needed. Dimming and boosting should not affect the spectrum of your CMH lamp, and only boosting should impact the lifespan.
 
White Beard

White Beard

Active member
What kind of impact would you expect from running @ 700? Have y’all run a bulb down to see how it handles the exposure?

My main interest in having a dimmable ballast is to see if plants react to subtler seasonal signals than on and off. Part of that could be bringing 700w to simulate late-summer.

I’m a researcher at heart: I don’t think it will make a difference, I want to find out if it makes a difference. I like options that give me latitude in my choices.
 
G

gh0stm0de

Active member
Hey Whitebeard,

Frozen Fire has posted his experiences running at 700W here:

https://www.icmag.com/ic/showthread.php?t=344873&page=39

He was able to hit 1.52 GPW @ 700W without monocropping or prioritizing yield as primary goal. Never seen a flower from his garden that wasnt dipped in sugar either.

Your increase in PPFD will be pretty directly proportionate to the increase in wattage. So you could expect 720~ PPFD @ 2ft (center point) with 630W, or approximately 780~ when bumped up to 700W. Specific bulb and reflector used will influence these numbers, and they are relevant for 630DE not 2x 315SE. You should not experience deviation in spectrum as a result of boosting your CMH lamp.

:smoke out:
 
G

gh0stm0de

Active member
Regarding lifespan, the primary limiting factor for CMH seems the ballast. High frequency ballasts can significantly limit lifespan, in some cases to just months. When operated by low frequency square wave ballasts, they can see 20,000 hours of use. So far @ 700W, lamps see over a year of use, so the reduction in lifespan is not so dramatic.
 
White Beard

White Beard

Active member
Thank you, sir, I consider that good news...tho I wonder how many ‘overclock’ their lamps?

Your rig is the most appealing to me, at the same time, there’s little word around about the DE bulbs, and how they compare to dual-lamp models. Especially I don’t see/hear anything about the DE versus the Philips bulbs.

The dual-lamp crowd never seem to talk about their lights, just their harvests, that could be a hint or just growers growin’
 
R

rastafari80

pecor said:
Dimming would be Handy, When working on your plant's. Bit easier on the old eyes!
Click to expand...


it's not meant to be used for this purpose.
you have to shut off the light for at leat 10 minutes before any switch.
not a huge problem, anyway it's very unpratical compared to any anti-uv sunglasses
 
R

rastafari80

do you think so? well, it's what the manifactures usually recommends: never dim the light when it's on. the dimming has to be done before switching.
sounds safer, anyway you can do what you want with a bulb.
 
G

gh0stm0de

Active member
No, I know so, I am a vendor. You may freely switch between wattage of these low frequency square wave ballast without concern. That said, there is no real reason for quick successive dimming adjustments.
 
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