Can I use a 400w standard magnetic ballast on a 315w cmh bulb?

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I understand old school magnetic ballasts (typically for MH or HPS bulbs or convertible) work fine for CMH bulbs. True? Is a 400w sufficient? I understand I’d need a socket adapter if the cmh reflector socket set is mogul.
 
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What size is your ballast ?
Most 400 watt bulbs, have a M59 ballast .
Well I have a couple. But they’re both digital. I’m not considering those.

I just considered picking up a secondhand unit. I’ve seen a few go in the $25-30 range so I figured if it worked 🤷‍♂️

There’s a BUNCH of snake oil being peddled in the ceramic metal halide ballast world. Best I can tell they basically re-badged specific 315w ballasts and act like it’s some new tech. It’s not. The tech is in the gas mixture in the bulb. Some of these fancy cmh ballasts are overpriced old tech with a new product code...it’s kinda lame.

Best I can tell from reading people have had success using them. I think worst case scenario they’re slightly inefficient as the thing will pull a little more than it needs.
 
There are several 400w CMH bulbs out there with a mogul base available that will run off of old stye MH and HPS ballasts. GE and Phillips have them. For MH ballasts:


This is a conversion mogul base CMH bulb that will run in an 400w HPS ballast and its half the price:


It looks like I can use my old school 400W HPS and MH switchable ballasts and run CMH in them. The future looks bright!
 
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The real question is gonna be bulb life and color temp. I think you will be dealing with what happens when you turn a 1000w light down to 600w and the spectrum shift. At 80 bucks plus a bulb or more sometimes frying 2-3 bulbs over the cost of saving money on a ballast isnt going to add up. Not to mention doubt you would get any type of warranty on the bulbs going this route. Which btw all of my philips bulbs I have had problems with they warrantied with zero questions. Even when it was the nano ballasts. So saving the money in the end might just be wasting money.

Up to you. You could prob make it work. Will it be the most efficient or have the longevity? Who knows. The selling point of these bulbs and DE is output vs longevity. If messing with that better off sticking with just a 400w bulb. Cheaper and no guess work. They change the socket on these things for a reason. Also look at the reviews of the conversion mogul lamps. The opinion is they are mostly trash. I don't even think philips sells them anymore.
 
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Well I have a couple. But they’re both digital. I’m not considering those.

I just considered picking up a secondhand unit. I’ve seen a few go in the $25-30 range so I figured if it worked 🤷‍♂️

There’s a BUNCH of snake oil being peddled in the ceramic metal halide ballast world. Best I can tell they basically re-badged specific 315w ballasts and act like it’s some new tech. It’s not. The tech is in the gas mixture in the bulb. Some of these fancy cmh ballasts are overpriced old tech with a new product code...it’s kinda lame.

Best I can tell from reading people have had success using them. I think worst case scenario they’re slightly inefficient as the thing will pull a little more than it needs.

No snake oil. The 315 cmh by phillips has new hotter burning gasses for better spectrum and requires a new socket and a low frequency square wave ballast to run it to spec.

All the other hid ballasts are high frequency.
 
You can get a new 400w MH mogul base bulb for all of $12 online now at 1000bulbs. Cheap as chips. If they last half as long, big woop. They are 7x cheaper than CMH. 400w HPS lights are about 40% brighter than MH, and 20% brighter than CMH. 50k lumens for HPS vs 36k lumens for MH, and 41k lumens for CMH in the 400w range. So old school HPS would be the biggest bang for the buck. Ligtht falls off at the inverse square of the distance from the source though, and so in reality, all indoor lights suck compared to the sun. Any indoor light. LED, HID, M-O-U-S-E. Simple physics.
 
Those are not the new tech. They do not put out a similar spectrum or intensity.

The new base 315 cmh is the bulb that requires square wave. Which drastically increases its output over the old 400.
Sorry, you are wrong here. These are new tech CMH in a mogul based bulb. Yes, new. Not old school MH. They are not 'drastically' different. They are marginally different, by all of 2.4% better for the 315 CMH bulb over the 400w CMH bulb. If you do the math comparing the lumen output per watt, since you seem to like lumen comparisons so much. Actually the mogul based CMH bulb is a LOT brighter. 41k lumen vs. 33k lumen. The expected life span is the same. The color temps are the same range. The CRI is typically higher in 315w bulbs, a slight advantage, but that varies greatly between 315w bulbs. This information from GE, HTG and Phillips:

Specs from GE:

GE 400w CMH mogul based bulb
• 400 watts
• 41,000 lumens
• 20,000 hour lifetime
• 3,000K color temperature horizontal position
• 3600K color temperature vertical position

From HTG:

Ceramic metal halide (CMH) grow lights have developed quite a following in the indoor gardening industry. With a balanced spectrum and beneficial ultraviolet (UV), the output CMH bulb is closer to natural sunlight than any other type of HID grow light bulbs available. Our HTG Supply Value Series CMH system featuring the GE 400w ceramic metal halide bulb provides the bright white spectrum of a typical MH lamp combined with the powerful red spectrum of the HPS lamp for outstanding growth and excellent efficiency for outstanding growth and yields.

Typical 315w CMH bulb specs from Phillips:
  • 315 watts
  • 33,000 lumens
  • 20,000 hour lifetime
  • 3,000K-4,200k color temperature
 
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Sorry, you are wrong here. These are new tech CMH in a mogul based bulb. Yes, new. Not old school MH. They are not 'drastically' different. They are marginally different, by all of 2.4% better for the 315 CMH bulb over the 400w CMH bulb. If you do the math comparing the lumen output per watt, since you seem to like lumen comparisons so much. Actually the mogul based CMH bulb is a LOT brighter. 41k lumen vs. 33k lumen. The expected life span is the same. The color temps are the same range. The CRI is typically higher in 315w bulbs, a slight advantage, but that varies greatly between 315w bulbs. This information from GE, HTG and Phillips:

Specs from GE:

GE 400w CMH mogul based bulb
• 400 watts
• 41,000 lumens
• 20,000 hour lifetime
• 3,000K color temperature horizontal position
• 3600K color temperature vertical position

From HTG:

Ceramic metal halide (CMH) grow lights have developed quite a following in the indoor gardening industry. With a balanced spectrum and beneficial ultraviolet (UV), the output CMH bulb is closer to natural sunlight than any other type of HID grow light bulbs available. Our HTG Supply Value Series CMH system featuring the GE 400w ceramic metal halide bulb provides the bright white spectrum of a typical MH lamp combined with the powerful red spectrum of the HPS lamp for outstanding growth and excellent efficiency for outstanding growth and yields.

Typical 315w CMH bulb specs from Phillips:
  • 315 watts
  • 33,000 lumens
  • 20,000 hour lifetime
  • 3,000K-4,200k color temperature

No. The spectral output is much wider and the peaks higher with the square wave driven bulb. You conveniently left out the main improvement in your argument.

And HTG is a discount company selling the old ge bulb. It had many reports of bad quality. Bet they got them real cheap. Says “value series” in the info you printed.

The phillips 400w cmh bulb was the better one when they came out according to all info I have seen but phillips greatly improved the tech. Ge did not. They were designed for magnetic ballasts even.

You only need to look at the spectral chart. And phillips explains about the low frequency ballast with higher steady output, the new better gasses. (They produced the old 400 first) and less harmonic distortion from the new base.

And the university of utah names the new phillips bulb the best plant growing lamp on the market. No mention of the old cmh.

I did a lot of research before buying mine.

And im still dissapointed in its performance compared to my 600 hortilux hps bulbs. Lots of hype and mis information on the weed forums.


Like comparing the old cmh to the new one. The old one was developed to light storefronts and other retail space needing accurate cri.

The new one was developed to grow plants.
 
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You can get a new 400w MH mogul base bulb for all of $12 online now at 1000bulbs. Cheap as chips. If they last half as long, big woop. They are 7x cheaper than CMH. 400w HPS lights are about 40% brighter than MH, and 20% brighter than CMH. 50k lumens for HPS vs 36k lumens for MH, and 41k lumens for CMH in the 400w range. So old school HPS would be the biggest bang for the buck. Ligtht falls off at the inverse square of the distance from the source though, and so in reality, all indoor lights suck compared to the sun. Any indoor light. LED, HID, M-O-U-S-E. Simple physics.
Have you run 315's at all? Like over some plants?
 

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