315 cmh vs led

the cooling in led light bulbs is horrible and the leds are driven quite hard normally.
also there are huge diferences between good and bad brands.

i dont think its fair to compare a CMH 315 watts to 315 watts of modern led light, as you need just about half the wattage for the same ppfd output.
a CMH is 1.4 per watt,maybe 1.5, a modern led fixture is easily 2.8.

Rurumo said:

idk, all I know is I end up having to replace my led bulbs that go into my incandescent lamp fixtures as often as regular light bulbs, and those were supposed to last for a decade, it says so on the box!!

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Wouldn't happen to be ecosmart bulbs from hd? They do have high failure rates ime. Osram sylvania & philips have lasted years no issues.

Also most led bulbs aren't enclosed fixture rated(heat), says so on the box too..... Cuts the longevity severely.


Edit .... Philips 315w 3100k cmh bulb is 1.96ppf/w new bare (age& reflector could add +30% loss).

PSUAGRO. said:

Any cmh/lec/cdm fixture with a Phillips ballast(240v)/ Phillips bulb(3100k) combo. Sunsystem is one that I know of , the model which has the bulb running vert.

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Hi, thanks for responding. I am preparing for my first grow. You guys must be tired of us by now. I am old bench tech, and notorious tool guy. I want to start my grow with cmh in a 3x3. I look to the horror stories first. It seems its hit or miss with these ballasts. Get a good one, great, get a bad one, and company doesnt take your call. So which is the best cmh square wave ballast.. something bullet proof. Do I go magnetic, more heat, more wasted energy, but are they the benchmark for reliability? I have spent so many days digging around for a ballast that I am running out of steam. I see there is the ceramic MH 400w bulb. I would like to have the option to change bulbs for stages of growth, but maybe thats a pipe dream. The heat, I see folks here talking about 400w lamps and the heat they produce. My goal is to get the spectrum covered properly, and I also cant find data on how much UV or IR they deliver. Some experienced control freak grower should tell me I'm either out of my mind, or I'm overthinking this, or help me choose my ballast/lamp/gro phase choices. WOW.. this is longer than I wanted. As I am an old guy, and totally new to not only growing, but this communications platform.. I figure I will put myself out here and see what happens. Thanks in advance for any help from anyone...

Montanan said:

Hi, thanks for responding. I am preparing for my first grow. You guys must be tired of us by now. I am old bench tech, and notorious tool guy. I want to start my grow with cmh in a 3x3. I look to the horror stories first. It seems its hit or miss with these ballasts. Get a good one, great, get a bad one, and company doesnt take your call. So which is the best cmh square wave ballast.. something bullet proof. Do I go magnetic, more heat, more wasted energy, but are they the benchmark for reliability? I have spent so many days digging around for a ballast that I am running out of steam. I see there is the ceramic MH 400w bulb. I would like to have the option to change bulbs for stages of growth, but maybe thats a pipe dream. The heat, I see folks here talking about 400w lamps and the heat they produce. My goal is to get the spectrum covered properly, and I also cant find data on how much UV or IR they deliver. Some experienced control freak grower should tell me I'm either out of my mind, or I'm overthinking this, or help me choose my ballast/lamp/gro phase choices. WOW.. this is longer than I wanted. As I am an old guy, and totally new to not only growing, but this communications platform.. I figure I will put myself out here and see what happens. Thanks in advance for any help from anyone...

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You are just looking for the ballast or for a complete fixture? I think most decent brands have 3 year warranties. I don't have any experience with the cheaper ones which are like under $200, but Sun System makes a decent product and I have a 630 CMH from Iluminar that I love-my cousin has a 315 from the same brand and his has been flawless.

Montanan said:

Hi, thanks for responding. I am preparing for my first grow. You guys must be tired of us by now. I am old bench tech, and notorious tool guy. I want to start my grow with cmh in a 3x3. I look to the horror stories first. It seems its hit or miss with these ballasts. Get a good one, great, get a bad one, and company doesnt take your call. So which is the best cmh square wave ballast.. something bullet proof. Do I go magnetic, more heat, more wasted energy, but are they the benchmark for reliability? I have spent so many days digging around for a ballast that I am running out of steam. I see there is the ceramic MH 400w bulb.

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I've used both the 400w retrofit CMH's (since way back when Phillips still made those lamps), and I've also purchased 3 different types of ultra-cheap Chinese knock-off 315 ballasts. I stick with Phillips lamps and they all work.

I moved away from the 400's due to the 315's having a superior light output mainly because the GE retrofit bulbs are not open rated so you have to put them behind glass, which blocks UV. The UV output is the 315's secret weapon that LED can't match.

The two on the left cost $150 each on Ebay, the two on the right cost $179 each on Ebay. I added SolarCure lights in between just for max UV but I probably don't need them.

7 weeks later...

Norml56 said:

The same would go for your LED strip light. If you could still sell it in 3 years let alone 10 I would be surprised.

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The point I was making was that LED is advancing and CMH/HPS is not. The strip build I have is worth more in terms of productivity than my CMH and it will be in another 3 years.

Norml56 said:

One of the main reasons I always tell people to go with a CMH is that it is the cheapest best light you can buy and 99% of the people getting into this hobby quit after 2 or 3 runs.

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If we're basing this on someone in it for the short term then they might as well get a 400w HPS and a parabolic hood for less than half the price and be done with it.

Norml56 said:

Do you actually use GPW as a measurement of efficiency? lol, I always looked at GPW as a dick-measuring contest for online forums at best.

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Yes of course I base the efficiency of a fixture on it's productivity. All gardeners should do. What other metric is there to use that you know of?

I'm not here to measure my dick against anyone else, but if I give my results honestly then it adds to the info that's already out there, and the numbers do not lie. I wouldn't log on here and pretend I can get this number when I can't, I'd be trying to improve my results.

My LED fixtures have been a game changer for me, and I'm sharing that experience. They've changed the efficiency of my space way beyond what I could have expected. I'm grateful for the people on here who helped me to build them and who also shared their opinions on what is possible with them, a lot of which involved the GPW measurement.

You're ignoring some key variables and choosing to focus on other issues which may or may not be a concern to most growers, such as them quitting growing, and how much bulbs cost. Those factors might be relevant to a small niche group, but to me and most others on here that's pointless.

To dismiss yield per watt of electricity as if it doesn't matter is removing one of the key data in the comparison, and imo you'd only do that if you didn't want the comparison to reflect the fact that an LED fixture is simply more efficient and will grow you more weed, and if we really narrow this down to what matters to the average grower, that's probably it.

DukeFluke said:

What other metric is there to use that you know of?

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There is one gigantic measurement that a lot of people look at for success. Guess what it could be.

PSUAGRO. said:

Wouldn't happen to be ecosmart bulbs from hd? They do have high failure rates ime. Osram sylvania & philips have lasted years no issues.

Also most led bulbs aren't enclosed fixture rated(heat), says so on the box too..... Cuts the longevity severely.


Edit .... Philips 315w 3100k cmh bulb is 1.96ppf/w new bare (age& reflector could add +30% loss).

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youre right.

not 100% up to date, newest here is a just a COB, mid power led with 3 ppfd/watt is missing.
you have 15% losses in the reflector for the CMH.
lets say 200W recent led tech is easily comparable to a 315cmh light output wise.

a mongo frog said:

There is one gigantic measurement that a lot of people look at for success. Guess what it could be.

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HPS?

DukeFluke said:

HPS?

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Nope.

Norml56 said:

The same would go for your LED strip light. If you could still sell it in 3 years let alone 10, I would be surprised. One of the main reasons I always tell people to go with a CMH is that it is the cheapest best light you can buy and 99% of the people getting into this hobby quit after 2 or 3 runs. Do you actually use GPW as a measurement of efficiency? lol, I always looked at GPW as a dick-measuring contest for online forums at best.

Click to expand...

Norml56 said:

The same would go for your LED strip light. If you could still sell it in 3 years let alone 10, I would be surprised. One of the main reasons I always tell people to go with a CMH is that it is the cheapest best light you can buy and 99% of the people getting into this hobby quit after 2 or 3 runs. Do you actually use GPW as a measurement of efficiency? lol, I always looked at GPW as a dick-measuring contest for online forums at best.

Click to expand...

Rurumo said:

You are just looking for the ballast or for a complete fixture? I think most decent brands have 3 year warranties. I don't have any experience with the cheaper ones which are like under $200, but Sun System makes a decent product and I have a 630 CMH from Iluminar that I love-my cousin has a 315 from the same brand and his has been flawless.

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I was just reading an email from them and looking at their lights. THANKS Norml
This is what I was hoping for, straight feedback from growers.

a mongo frog said:

There is one gigantic measurement that a lot of people look at for success. Guess what it could be.

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Cock size ?

cobshopgrow said:

the cooling in led light bulbs is horrible and the leds are driven quite hard normally.
also there are huge diferences between good and bad brands.

i dont think its fair to compare a CMH 315 watts to 315 watts of modern led light, as you need just about half the wattage for the same ppfd output.
a CMH is 1.4 per watt,maybe 1.5, a modern led fixture is easily 2.8.

Click to expand...

I think this where I get confused or leary about using GPW as a good measurement. It's hard to believe people when they talk about GPW, but if I was hitting 1 GPW with my 315 and then swapped it out with half the wattage of LED I would need to hit 2 gpw to have an equal return. I don't see many folks saying they are hitting 2 gpw with LED, usually around 1.5 which would mean a 79gram reduction in yield. If you are going with the route that Duke is with an almost 1:1 replacement in wattage it makes sense that he would be seeing better yields, but also defeats the main purpose of switching to LED which is reduced heat - reduced electrical cost.
I know a lot of people on this forum don't like Hybridway or the way he conducts his side by sides, but after his side by side with CMH and I believe it was the diablo boards from HLG the CMH won far as yield goes.

I can tell you I just hit 1.5 gpw off of 4 plants under 600W Cobb with 3 weeks veg and 8 flower for a total of 900grams. I got plant number limits and growing in tents so I can't veg for longer to get a better yield nor add more plants, if I could I think it would be pretty easy to get close to 2gpw. And I'm not an awesome grower, just a solid grower. Same setup I would only hit 0.8 gpw with a crappy HPS and crappy hood.

GrownAtHighAltitude said:

I've used both the 400w retrofit CMH's (since way back when Phillips still made those lamps), and I've also purchased 3 different types of ultra-cheap Chinese knock-off 315 ballasts. I stick with Phillips lamps and they all work.

I moved away from the 400's due to the 315's having a superior light output mainly because the GE retrofit bulbs are not open rated so you have to put them behind glass, which blocks UV. The UV output is the 315's secret weapon that LED can't match.

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THANKS.

Rurumo said:

You are just looking for the ballast or for a complete fixture? I think most decent brands have 3 year warranties. I don't have any experience with the cheaper ones which are like under $200, but Sun System makes a decent product and I have a 630 CMH from Iluminar that I love-my cousin has a 315 from the same brand and his has been flawless.

Click to expand...

Just ballasts,
I am going for the parabolic reflector, and two ballasts. I wish I had a spectrograph tool. I would like to put some of those china lights to the test. I spent a week collecting spectrum charts from every bulb that posted them so I could choose the best. There is a $50 chin lamp that "says.." it has a great spectrum. I will be trying one, but will have a couple of real lamps for backup. I am sure you get what you pay for, but in my search I have found there are factories producing multiple brands of transformers, same thing $100..Same thing diff name $200.
If they are coming from the same factory, am I am going for the econo brand? The luminar is china, Norml says get philips, thats mexican as of recently, but the price difference is big. Thanks much Rurumo..

DaFreak said:

I can tell you I just hit 1.5 gpw off of 4 plants under 600W Cobb with 3 weeks veg and 8 flower for a total of 900grams. I got plant number limits and growing in tents so I can't veg for longer to get a better yield nor add more plants, if I could I think it would be pretty easy to get close to 2gpw. And I'm not an awesome grower, just a solid grower. Same setup I would only hit 0.8 gpw with a crappy HPS and crappy hood.

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That's really what I'm talking about. Most people replace a 1000 watt HPS with around 600watts of LED or at least that's what I'm told will replace it. I'm still skeptical about that number. A lot of people are able to hit 1gpw with a 1k HPS so if you can hit 900 with LED you lost out on 100 grams. You saved a few pennies on electrical but I'd rather have the 3.5 ounces. From what I can tell to truly increase your yield you need to do a 1:1 replacement. I would bet that 99% of the people using LED are in the same situation as you with height/sq ft restrictions because of tents.

Brettman said:

Cock size ?

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Close but no.