315 cmh vs led

nobighurry

Well-Known Member
How often do you guys switch out your CMH bulbs? I have about a year on mine, they in flower rooms so they only run 12hrs a day, but there is always plants in them so they run 12 months a year.. Thanks
 

GrownAtHighAltitude

Well-Known Member
I did not have very good luck with Phillips bulbs, they came with the prism ballasts, both failed within weeks of each other, I switched to igrow tech but was not impressed with growth/terps, Ushio treated me good in my hps hoods so I gave their CMH bulbs a few runs, perhaps I had a bad batch and need to try Phillips again...
That's more likely to be a problem with the ballasts, or else you got used bulbs somehow. They work great for me.
 

nobighurry

Well-Known Member
That's more likely to be a problem with the ballasts, or else you got used bulbs somehow. They work great for me.
At first I suspected the ballasts, but the latest bulbs have lasted a year, I suspect used bulbs could be the culprit alright, I will give Phillips another shot, the bulbs in one room are about a year old, how often do you change your bulbs? I read 20,000 hours, every year, & every 8 months... I have been an hps user since 80s, LEDs and CMH are fairly new to me.....
 

finku

Active Member
At first I suspected the ballasts, but the latest bulbs have lasted a year, I suspect used bulbs could be the culprit alright, I will give Phillips another shot, the bulbs in one room are about a year old, how often do you change your bulbs? I read 20,000 hours, every year, & every 8 months... I have been an hps user since 80s, LEDs and CMH are fairly new to me.....
What ballast?
 

nobighurry

Well-Known Member
Ah ok not familiar with those, looks like a LFSW though. Just thought it might have been a HF ballast like the Dimlux that don't play well with Philips.
The ballasts came with Phillips bulbs, recently been doing some recon, appears bulb failure is rare, as someone suggested I may have gotten used bulbs, I ran into new/used hps, I was new to CMH back then, i have nothing to compare these ballasts too, I always ran hps before, still do if plants get too tall, thanks for your help...
 

nobighurry

Well-Known Member
At first I suspected the ballasts, but the latest bulbs have lasted a year, I suspect used bulbs could be the culprit alright, I will give Phillips another shot, the bulbs in one room are about a year old, how often do you change your bulbs? I read 20,000 hours, every year, & every 8 months... I have been an hps user since 80s, LEDs and CMH are fairly new to me.....
In my experience i have seen a big drop off in yields after 12 months of use 2 dimlux cmh 315s & 1x philips 3100k in my maxibright cmh. They guy in the grow shop reckons the claim that the bulbs retain 80% output after 20,000 is bullshit from experience id agree with him.

Also the dimlux fixtures tune up to 380w, I suspect running them at 380w wears the bulb out a little faster too although they were supplied with dimlux bulbs.

Cmh produces some top quality weed but the yield for me was never there.

Im running a HLG 650r along side 2 x315s now and the HLG side is so much brighter. I can't comment on the led side for quality yet but its looking promising. Just trying to get the feed dialed in my plamts seem way more hungry than usual under the 650r.
 

MidnightSun72

Well-Known Member
So @6mo my Chinese CMH bulbs are basic at garbage they are way dimmer it's visible by eye. And also they fail to ignite sometimes. But the philips seem to be doing fine still read well on the lux meter.
 

SauronBlue

Active Member
85% PPF maintenance at 20,000 hr. I only run my CMH in flower so I'm only changing them every 3 years. 15% reduction in light at 20,000 hours is fairly minimal IMO. $160 for 2 bulbs so about $50 a year in bulbs is totally doable for me.
The life expectancy that you speak of is for continuous use. Starting up the bulb takes way more energy and causes way more wear and tear on the bulb than running it non-stop, so if you are turning the light on and off each day you won't get anywhere near 20,000 hours out of it
 

Norml56

Well-Known Member
The life expectancy that you speak of is for continuous use. Starting up the bulb takes way more energy and causes way more wear and tear on the bulb than running it non-stop, so if you are turning the light on and off each day you won't get anywhere near 20,000 hours out of it
Even if I got 10,000 hours of it that's still 2.2 years before changing bulbs running on the flower side. or about 14 harvests at 1gpw that's around 10lbs of weed grown with an 80 dollar bulb. I think I can afford that.
 

nobighurry

Well-Known Member
I am going to pop the bulb out and check the date I wrote on the ceramic base when this run finishes, that bulb has been in the longest over a year now, I swear it seems less bright the last couple weeks, we had many power failures due to weather the last few weeks poor bulbs were on, off ,on several times a day, but the plants seem happy so it's likely my imagination, my next purchase is going to be a quality light meter, thanks guys good info
 

DukeFluke

Well-Known Member
I'd never even think for a second about switching back to my 315 cmh from the 320w bridgelux strip build I knocked up. There's no comparison between the two fixtures, the LED whoops it's ass all round the garden

I used to like my CMH too :cry:
 

Rurumo

Well-Known Member
I'd never even think for a second about switching back to my 315 cmh from the 320w bridgelux strip build I knocked up. There's no comparison between the two fixtures, the LED whoops it's ass all round the garden

I used to like my CMH too :cry:
comparing apples to oranges-initial price is a big factor we're looking at when considering CMH fixtures. A 315 CMH kills an equivalent priced LED at the lower end of the price scale-a more direct comparison factoring in price would be a Vivisun 315 vs a Spider Farmer 1000 (I think, not too familiar with them), both are around $150. CMH would win hands down in that example.
 

DukeFluke

Well-Known Member
comparing apples to oranges-initial price is a big factor we're looking at when considering CMH fixtures. A 315 CMH kills an equivalent priced LED at the lower end of the price scale-a more direct comparison factoring in price would be a Vivisun 315 vs a Spider Farmer 1000 (I think, not too familiar with them), both are around $150. CMH would win hands down in that example.
It's not apples vs oranges, It's just a standard priced LED fixture vs a standard CMH. Why use a shit LED as the benchmark just because it's the same price? I think the OP already knows the price of an LED is going to be a bit more than another CMH bulb, but it doesn't have to be a massive amount more.

If the aim of the thread is to find opinions simply on which one is best then price shouldn't be considered unless the OP is asking specifically for that metric to be applied. To me it's pointless. You're growing cannabis, so what the fuck is the point quibbling over a hundred dollars when you'll save that back immediately in ounces of weed you don't have to buy.

The LEDs have rendered my CMH bulbs and reflectors obsolete. They're stuck away not being used. I have no intention of getting them out again. It's that clear cut. I wouldn't have one in my room again if they were being given away free because there's no point in them anymore.

I think anyone who uses a light with the footprint and efficiency of a 320w 4ft x 2.5ft Samsung/B'lux build will feel exactly the same. There's no going back
 

Norml56

Well-Known Member
It's not apples vs oranges, It's just a standard priced LED fixture vs a standard CMH. Why use a shit LED as the benchmark just because it's the same price? I think the OP already knows the price of an LED is going to be a bit more than another CMH bulb, but it doesn't have to be a massive amount more.

If the aim of the thread is to find opinions simply on which one is best then price shouldn't be considered unless the OP is asking specifically for that metric to be applied. To me it's pointless. You're growing cannabis, so what the fuck is the point quibbling over a hundred dollars when you'll save that back immediately in ounces of weed you don't have to buy.

The LEDs have rendered my CMH bulbs and reflectors obsolete. They're stuck away not being used. I have no intention of getting them out again. It's that clear cut. I wouldn't have one in my room again if they were being given away free because there's no point in them anymore.

I think anyone who uses a light with the footprint and efficiency of a 320w 4ft x 2.5ft Samsung/B'lux build will feel exactly the same. There's no going back
You are also comparing a DIY LED to a plug and play CMH. If you can find a plug and play 320watt LED strip light that's around $200 I would like to know where, and not Alibaba. I do think for your situation the strip build for sure wins in a micro grow.
 
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