# 400w MH bulb for 600w ballast?



## andy7000 (Oct 2, 2008)

Can i use a 400w Mh bulb with a 600w HPS/MH Maxibrite ballast?Reason for asking,i want to use a MH bulb but i dont want to buy another ballast?


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## Bifta (Oct 2, 2008)

lol wot do you think ?


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## andy7000 (Oct 2, 2008)

Bifta said:


> lol wot do you think ?


I dont know how you found that question funny.Have you tried it?
If I knew the answer,I wouldnt have asked the question.


I cant imagin using a 1000w bulb with a 600w ballast,but can a person use a 400w bulb with a 600w ballast?
Has anyone tried it?
Will it blow?


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## Seamaiden (Oct 2, 2008)

Smaller bulb with larger ballast is your question, yes?


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## andy7000 (Oct 2, 2008)

Seamaiden said:


> Smaller bulb with larger ballast is your question, yes?


Yes.Would a 400w be compatible with a 600w ballast? Simple question, has anyone tried it?will it blow the bulb?I dont know how to put it any clearer.


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## Dirtyboy (Oct 2, 2008)

If the ballast is a 600 hps put a 600 mh bulb in.


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## andy7000 (Oct 2, 2008)

I am asking a simple question, has any person connected a 400w bulb to a 600w ballast?
Will it blow?


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## andy7000 (Oct 2, 2008)

I want to learn by someone elses mistake and not my own lol.


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## SpruceZeus (Oct 2, 2008)

I haven't done this, but common sense would lead me to believe that pumping too much power through a 400 would blow or at very least drastically shorten the life of a bulb. I wouldnt do it if i were you!


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## Dirtyboy (Oct 2, 2008)

Dirtyboy said:


> If the ballast is a 600 hps put a 600 mh bulb in.


 I know this will work.

The other i would not try.


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## andy7000 (Oct 2, 2008)

One of my mates can use a 250w MH bulb in his 600w Aurora ballast,but his says on the reflector that he can use bulbs from 250w to 600w.Now, has anyone tried a 400w bulb in a 600w ballast?


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## andy7000 (Oct 2, 2008)

Why will i die?You've answered my question,so YOU must be dead.
And again,has anyone tried a 400w bulb in a 600w ballast?


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## Dirtyboy (Oct 2, 2008)

No no one has. Are you going to beat this thread to death. Read some of the answers. We will stop helping you.


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## MisterMicro (Oct 2, 2008)

no, i just witnessed my friend fry alive, im good.

Im pretty sure that would be bad though, i know a higher watt bulb in a lower watt ballast sucks up more energy than the ballast can put ouf reducing its life drastically. I couldnt imagin it would be better switching it up...


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## hydrogrower420 (Oct 2, 2008)

nobody has tried it i think everybody would be smart enough just to buy a new 600watt bulb..either you can try it and risk waisten a couple 100 bucks on fucken up the ballast and the bulb or just spend the 50 bucks for a new bulb..


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## andy7000 (Oct 2, 2008)

How do you all know that nobody hasnt tried it?
I asked a question and people come on and say what they think might happen.Thats whats wrong with this site.When a person asks a question they get an answer from some people who think they know the answer.I want an answer from a person who has done what i'm asking.I'm not saying most people have tried it,but i'm thinking of it,and i'm damn well sure other people have thought what would happen if they did it.
Now,if you cant answer the question,or link me to a discussion about it,DO NOT POST A REPLY TO THIS QUESTION!


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## SpruceZeus (Oct 2, 2008)

andy7000 said:


> How do you all know that nobody hasnt tried it?
> I asked a question and people come on and say what they think might happen.Thats whats wrong with this site.When a person asks a question they get an answer from some people who think they know the answer.I want an answer from a person who has done what i'm asking.I'm not saying most people have tried it,but i'm thinking of it,and i'm damn well sure other people have thought what would happen if they did it.
> Now,if you cant answer the question,or link me to a discussion about it,DO NOT POST A REPLY TO THIS QUESTION!


I'm breaking your rule here, so sorry for that, but jesus h man, whats wrong with this site is not people giving their opinions, its when they state them as fact that it becomes a problem, if i were you i'd just be nice, and be patient, someone might have tried this and found okay results, but i wouldnt get my hopes up, overpowering a thin piece of untempered glass doesnt sound like a good idea to me, but we would still be in the stone ages if people were afraid to take risks.

sorry im pretty blitzed and got off track a bit there, long story short, be nice! itll get you alot further than demanding things.
good luck and happy growing!


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## fitzyno1 (Oct 2, 2008)

Ok i'm not breaking your rules, heres a link to a discussion about what you're asking.
UK420 > 400w Ballast & 600w Lamp.

I've thought about what you're asking, i see your point of view, it would be nice to use the same ballast through-out a grow. Saves chopping and changing things. Maybe in the future it could be possible.

What do you mean your mate uses a 250w with a 600w ballast? Is it working for him?


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## andy7000 (Oct 2, 2008)

SpruceZeus said:


> I'm breaking your rule here, so sorry for that, but jesus h man, whats wrong with this site is not people giving their opinions, its when they state them as fact that it becomes a problem, if i were you i'd just be nice, and be patient, someone might have tried this and found okay results, but i wouldnt get my hopes up, overpowering a thin piece of untempered glass doesnt sound like a good idea to me, but we would still be in the stone ages if people were afraid to take risks.
> 
> sorry im pretty blitzed and got off track a bit there, long story short, be nice! itll get you alot further than demanding things.
> good luck and happy growing!


Sorry for being rude.I've being reading RIU for quite a while,and I see more and more that people answer questions on what they think,instead of answering a question about facts.
This thread is a plain example,first someone laughs at a question i ask (which fuckin annoying),then someone says i'll die,then someone has the check to tell me to read some of the answers or they'll will stop helping me. Read some of the answers?Nobody answered my question!So again,I'm sorry for being rude.

Thank you for the link fitzyno1.
Yes my mate has a 600w Aurora ballast and every grow he uses a 250MH bulb for his seedlings,and then changes to his 600HPS.BUT,his light kit is one unit,with timer built in.Thats why i ask can any other ballast do the same as his,only with a 400wMH bulb.


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## Seamaiden (Oct 3, 2008)

SpruceZeus said:


> I haven't done this, but common sense would lead me to believe that pumping too much power through a 400 would blow or at very least drastically shorten the life of a bulb. I wouldnt do it if i were you!


I would worry about that as well, OR the bulb not burning properly (emitting the spectra you're after). However, do I know it for a fact? No, I do not. I don't know if you can do as you can with, say, incandescents, for instance when you've got a lamp rated for up to 100W but you put in a 40W. In part, in large part actually, because those fixtures do not require a ballast to start the lamps in the first place.

Have you started at the simplest place and done some Googling? I know for a fact there's a pretty good Wiki on MH bulbs in general, and I believe it goes into the differences between the ballast types (digital, pulse start, something else I don't recall) and so on. Looked pretty good to me, though it seemed to be geared primarily for reef aquarists.


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## benson (Oct 3, 2008)

andy7000 said:


> How do you all know that nobody hasnt tried it?
> I asked a question and people come on and say what they think might happen.Thats whats wrong with this site.When a person asks a question they get an answer from some people who think they know the answer.I want an answer from a person who has done what i'm asking.I'm not saying most people have tried it,but i'm thinking of it,and i'm damn well sure other people have thought what would happen if they did it.
> Now,if you cant answer the question,or link me to a discussion about it,DO NOT POST A REPLY TO THIS QUESTION!


yes it will work, hold on, mayb it wont, it mite work, try it an let me no. stick a 400 in ur mouth and a 600 up ur arse an see witch 1 glows the britest.


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## undertow (Oct 12, 2008)

Wow, I had this same question, got here thru Google (not RIU, even tho I'm a member), I can't believe the endless parade of people who tell the OP to "read the post," even though EVERYONE who attempted to answer the question didn't "read the question!"

There should NOT be 3 pages of posts here, without ONE valid answer. Somebody out here has to understand the intricacies of ballast power supplies, no? Is a 600W ballast capable of putting out 100-600W or ONLY 600w?

I mean, I have a couple lamps here in my house, and they don't really care what bulbs I put in them... in that scenario, it's up to the BULB whether to spread 40W or 100W -- are ballasts the exact opposite?


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## mrbuzzsaw (Oct 12, 2008)

andy7000 said:


> Yes.Would a 400w be compatible with a 600w ballast? Simple question, has anyone tried it?will it blow the bulb?I dont know how to put it any clearer.


 i dont want to make you look crazy but what would you think would happen if you overload a bulb by 200 watts?


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## andy7000 (Oct 12, 2008)

undertow said:


> Wow, I had this same question, got here thru Google (not RIU, even tho I'm a member), I can't believe the endless parade of people who tell the OP to "read the post," even though EVERYONE who attempted to answer the question didn't "read the question!"
> 
> There should NOT be 3 pages of posts here, without ONE valid answer. Somebody out here has to understand the intricacies of ballast power supplies, no? Is a 600W ballast capable of putting out 100-600W or ONLY 600w?
> 
> I mean, I have a couple lamps here in my house, and they don't really care what bulbs I put in them... in that scenario, it's up to the BULB whether to spread 40W or 100W -- are ballasts the exact opposite?


thanks for understanding what i had to go thru,to try and get a strate answer.i was sick of this thread.so i did it anyway.i now have a 400mh bulb in my 600 maxibrite ballast.it work no problim.but no differnce to electric.
its not funny,i'm not dead,and i didnt get any help from this thread.so,thank u for the 3 pages of usless posts.i'll keep u post if the house burns down


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## SpruceZeus (Oct 12, 2008)

Just dont blame me when your bulb explodes, kills all your plants, and possibly you and your family.
on the plus side, you saved 25 bucks.


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## andy7000 (Oct 12, 2008)

SpruceZeus said:


> Just dont blame me when your bulb explodes, kills all your plants, and possibly you and your family.
> on the plus side, you saved 25 bucks.


why wud i blame u?hav u tried it,and gave me any information to back up a fact?i hav, and its running fine for a week now,and nuthings happened.thank u but my plants and family r still alive.do u think id do this for 25 bucks,your full of facts,how do u know how much or what way it has saved me?


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## SpruceZeus (Oct 12, 2008)

I just dont understand why you wouldn't just buy a 600w bulb. I asked my electrician about this and he said its a very bad idea.


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## andy7000 (Oct 12, 2008)

SpruceZeus said:


> I just dont understand why you wouldn't just buy a 600w bulb.


maybe i have a brand new 400w mh bulb and my 600w hps is near done,does it matter?i asked a simple question to anyone who has tryed it.
and there u go again,did u ask ur electrican what happened when he had a 600w ballast and connected a 400w bulb to it?or is that an esumption,did he ever try it?


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## Packet. (Mar 18, 2009)

you might as well try it your self if your that curious


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## lostcompass3 (Jun 23, 2009)

there is a very good chance that this will blow out your bulb, i would not advise trying


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## obzcen (Sep 15, 2009)

this is my first post here ... i opened an account just for this .... silly thread  

based on my experience only i have to say that :

I USED A 400w hps lamp with a 600w digital ballast for a grow from start to end having no problems what so ever (lamp still has kick in it). 

some personal opinions :

I suspect (having nothing to back this up) that you will still consume 600w of electricity per hour instead of 400W as you might hope... 

If you have the option to use a perfectly tuned setup is always better to do so in order to avoid any possible faults and aspire for maximum yield ! 


so .... again for all pessimists, non-believers to conclude this thread and let it rest in peace with a proper answer for other generations of pot-heads to come :


YES YOU CAN USE A 600W BALLAST WITH LESS WATTAGE LAMPS LIKE 400W !


shizle ma dizle !


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## andy7000 (Sep 17, 2009)

A year later and i get an answer,
thank you abzcen, i also gave it a go myself, and it works fine, my house hasn't burned down and i'm still alive. I still use the ballast, which works perfectly.


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## cameron666 (Feb 19, 2010)

ive been looking for info on this for a little while now...i went to my mate house to get a light and he said its 600w....
well the ballast was but wen i got a look at the bulb it was a 400w grolux... the discharge tube inside was about an inch smaller than in the 600w bulb that he had spare...
i said this too him and he was only dissapointed about not using the extra 200Ws, he didnt think it would ever increase the risk of something fooking up... 

but anyway he used a 400w bulb in a 600w ballast for 2 grows...


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## kabona (Feb 21, 2010)

OK OK OK let me just clear this up for you because it appears that you are extremely slow in between the ears....... it would be in your best of interest not to continue using a 400watt bulb in your 600watt ballast... your ballast is rated for a 600 use a 600 watt bulb... your are drastically hurting your bulb also.... i can almost assure you that your bulb does not put out as many lumens as it did before... ok so now your saved your money on not buying another 600 watt bulb..... but now you can go out and buy another Mh (if you care). Also ... you have a 400 in a 600 ballast... thats .02 kwh your wasting every hour 18-24 hours a day. And lets say there was no problem with doing this.... what would be the point of people selling 250 watt and 400 watt ballast


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## thestonecutter (Jul 28, 2010)

relevant question deserves a relevant answer..here is mine from both experiance and knowledge. i use 400w on 600w ballast.. have done for years.. most i ever got from one bulb was 3 grows..i paid £13 notes for the bulb. Whenit blew i bought a new one. FFS. it's £13. IT AINT BREAKING NO BANK .the reason i do this is to save on forking out for cooling systems on 600watt bulbs.. my grows are small but large yields are obtained. 
The ballast provides the poke to strike the tube.. once it's struck the bulb takes what it needs from the ballast, not the other way round. as far as the bill debate. yup. it will put more money on than a 400watt ballast.. but not alot. and for the initial outlay of a 400w ballast.. id take the rise in bills anyday. good luck
Dave..(electrical engineer)


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## valuablevariable (Jul 30, 2010)

I was at a grow shop today and wanted to buy a 250w bulb for my 400w ballast and was told that you dont put a lesser or higher watt bulb into a ballast. It will turn on but not emit as much light and break a lot faster.


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## beezkneez (Apr 10, 2011)

You can use a lesser wattage bulb in a higher ballast. The ballast only puts out so much electricity that the bulb is asking for. Damn didnt anyone take even intro to electrical engineering in college? Go ahead and try some heat tests. Ive run 400w and 600w in my 1000w ballast for 3 years. No issues with less use of my bulbs and my ballast still runs fine. As far as heat, each bulb put off less. Based off what all these highschool kids have said, no matter the bulb if you put it in a 1000w ballast it will generate that heat. WRONG. Test it yourself. get some actually electric tools and run the tests your self, YOU FINE.




thestonecutter said:


> relevant question deserves a relevant answer..here is mine from both experiance and knowledge. i use 400w on 600w ballast.. have done for years.. most i ever got from one bulb was 3 grows..i paid £13 notes for the bulb. Whenit blew i bought a new one. FFS. it's £13. IT AINT BREAKING NO BANK .the reason i do this is to save on forking out for cooling systems on 600watt bulbs.. my grows are small but large yields are obtained.
> The ballast provides the poke to strike the tube.. once it's struck the bulb takes what it needs from the ballast, not the other way round. as far as the bill debate. yup. it will put more money on than a 400watt ballast.. but not alot. and for the initial outlay of a 400w ballast.. id take the rise in bills anyday. good luck
> Dave..(electrical engineer)



Most people running hydro shops dont know what the fuck they are doing. Ive talked to numerous owners and they all have different opinions. Its what they have heard on the internet as well! And im not just talking lighting. Im talking ventilation, nutrients, amount of light, amount of water, everything. Unless youve got someone that has grown for 40+ years and has done the tests himself they are full of shit.


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## Zcomfort (Apr 10, 2011)

No it want work. Put things in where they belong. You could blow the bulb, fuck your ballast up, are even cause a electrical fire.


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## choempi (Apr 14, 2011)

Yes, you can run a smaller watt bulb. Peeps that say otherwise are clueless.

On a side note, any mag hps ballast can run the same or lower watt mh bulbs, another thing peeps are ignorant of.


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## r1tony (Jul 26, 2011)

Jesus you have extra bulbs and you're not doing this yourself? Wtf man.. if you have a tampon in this time of the month ask your wife or girlfriend to screw the bulb in for you.



Zcomfort said:


> No it want work. Put things in where they belong. You could blow the bulb, fuck your ballast up, are even cause a electrical fire.



What? I sincerely hope you're stoned when you typed this.


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## skunkd0c (Jul 26, 2011)

This is simple ohms law 
as long as the bulb does not exceed the ballast rating it is fine and safe to run 
the ballast voltage for 400w and 600w are the same, the extra current needed to supply the 600w is possible because of the lower resistance of the 600w bulb 

problems would only occur if you put a higher rated bulb in a lower rated supply, the bulb being much lower in resistance than the supply it is intend for , would attempt to draw more current than the ballast could produce which would in-turn burn it out or short an internal fuse if it has one


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## choempi (Jul 26, 2011)

skunkd0c said:


> This is simple ohms law
> as long as the bulb does not exceed the ballast rating it is fine and safe to run
> the ballast voltage for 400w and 600w are the same, the extra current needed to supply the 600w is possible because of the lower resistance of the 600w bulb
> 
> problems would only occur if you put a higher rated bulb in a lower rated supply, the bulb being much lower in resistance than the supply it is intend for , would attempt to draw more current than the ballast could produce which would in-turn burn it out or short an internal fuse if it has one


Peeps that are buying mh conversion bulbs when they have hps ballasts and buying smaller ballasts to run smaller bulbs are duped


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## Growse (Sep 25, 2011)

It works ,your ballast might get a little bit hotter, but it works. Ive got a 400mh bulb in my 1000w ballast. Gets hot, but works fine if you have the proper saftey precautions.


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## gaztoth (Sep 25, 2011)

i put 600 in a 250 for a min lol it worked


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## chuckanders (Aug 26, 2012)

i have done it,it works,if its safe or not i cant tell you but it works


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## mother chuffer (Dec 2, 2012)

i was wondering the same would a 400 watt bulb work ok in a 600watt ballast ?


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## CDNSTEVE (Jun 21, 2013)

I recently just set my stuff up ,being all excited never give it much thought if my ballast was tuned properly? Light was working fine the whole two weeks since... when I looked, it was turned on 600w so switched it back . Differance was the heat of the bulb and brightness seemed to go more white then a yellow .Lost a few degrees which is nice . I think this is not great method and don't recommand it if you can get the proper ratio bulb to ballast .


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