400 watt bulb, in 1000 watt balis?

sure, as long as the ballast is rated 400Watt or above

the ballast may start to get hot as the coils will still generate the energy needed to power the 1000 watt bulb the 400 w bulb life may also be reduced as the ballast may spike (power serge)[SIZE=+0] the bulb its best to stick with the correct wattage bulbs that the ballast was designed for [/SIZE]one or both may burn out

Why would u not buy the right bulb? No matter whether u got the fixture for free or whatever the bulb is only about at the most 10$ Also a mh bulb will not light properly in a hps ballast & vice versa. DONT take shortcuts & always be prepared to live life as u see fit.

yeah thats not a good idea, i mean shit the ballast says 1000 watt mh for a reason

I have seen 250 watt MH bulbs run with 400 watt ballasts. They run the smaller bulb to 100% and the rest of the electricity is never realized. Bright, but not as bright as a true 400 watt set up.

I honestly don't even know... And apparently with over 2000 views a lot of other people don't know either.

Doesn't sound like a good idea, and get things wrong with this much power/heat and it might not be pretty.

Fires are one of the top ways grows are discovered. Just FYI

Its like running your family car on drag fuel, works fine for a short period then bang.
Iv seen reflectors melt with the wrong bulb to ballast marriage.

seattlewiseguyz said:

iam using a 400 watt MH in a 1000 watt ballis, that duz MH and SODIEUM bulbs,,is this ok?

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It will definately lead to quick bulb failure using a 1000W ballast to power the 400W bulb

MH bulb and HPS have different starting/igniting amps for the bulbs....A MH ballast will not start up a HPS bulb reguardless of wattage.

they make conversion bulbs for use in either system.....If you have a MH system your need a HPS conversion bulb for that system.

The four basic types of lamps considered as HID light sources are Mercury Vapor, Low Pressure Sodium, High Pressure Sodium, and Metal Halide. All are arc discharge lamps. Light is produced by an arc discharge between two electrodes at opposite ends of the arc tube within the lamp


How is lamp operation wattage of HPS lamps calculated?

The voltage of a typical mercury or metal halide lamp remains relatively constant throughout its operational life — for this reason, the lamp wattage regulation of these ballasts can be defined as a simple percent. High pressure sodium lamps, however, see significant arc tube increases during their operational life; therefore, the high pressure sodium lamp ballast must compensate for this changing lamp voltage (even with stable input voltages) to maintain constant lamp wattage.

Consequently, a simple percent is not an adequate definition for high pressure sodium lamp regulation. Instead, a trapezoid, established by the American National Standards Institute (ANSI), is defined, which restricts the operation of the lamp to certain acceptable limits with respect to lamp voltage and resulting lamp operation wattage. The ballast is designed to operate a high pressure sodium lamp throughout its life within this trapezoid for any input voltage within the rated input voltage range of the ballast. The resultant value of the lamp's actual operation wattage over the life of the lamp when shown on a graph follows a rising-then-falling path called a volt-watt trace.

vapedg13 said:

...A MH ballast will not start up a HPS bulb regardless of wattage.

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i do realize that this is an old post, and i hate for my first post on this site to be something negative, but bro, your full of shit. ive been growing marijuana for over 30 years, and i have on MANY MANY occasions used a STANDARD (NOT a conversion bulb) high pressure sodium bulb in a metal halide ballast without ANY issues whatsoever. i actually have several 600w HPS bulbs running on 1000w MH ballasts even as we speak, and ive been using the same bulbs for years. i have in the past installed "dimmer switches" in my ballast boxes ( which is very easy to do) and turned the lights down a bit, but generally i dont worry about it anymore.

ive also got 3 400w MH bulbs running off of 1000w ballasts right this second in my veg room, and have ran them like that off and on for years.

and while you CAN on occasion run a LARGER MH bulb on a SMALLER ballast, THAT WILL eventually burn your bulb up,or possibly your ballast. but it may take a couple of growing sessions to do so. you can prolong the life of your ballast by installing a couple of computer fans in the case for cooling. one thing you need to make sure of when you buy HPS or MH lights is how many hours a specific brand/wattage of bulb is usually rated for. youll find that on one brand, it may have, say a 24,000 hour rating, but on another brand of the same wattage, it may only have 3000 hour rating.

ive seen people blame bulb failures on several different things in then past like that, when in alot of the cases, it turns out that they had gotten oil from their hands on the bulb and blew them out that way.

I have a 400 watt bulb running on a 600 watt ballest, the ballest is on a paving slab am i ok? i will get a 600 watt bulb next week when i get some readies

I think if u get it rite u should u a lb if not 2!!!

I cant even find my lighter & u kids.

dude. noting personal, but WTF did you say?.......im fairly proficient in the english language , and man, i cant decipher a thing you said, or what it has to do with the subject of this post

i read alot about this even read people saying they were electricans? saying dont do it?? so since the 2 1000hps in my outdoor building run hot (92f)i bought 2 600w bulbs been running 7 wks now no probs and the killawatt shows it pulling 698kwh .69amps. if the 1000would damage a 600w bulb then the 60 amps coming into your house from the street would fry anything you plugged in to wall

very bad idea, dont do it. it may be a serious fire hazard, you could be damaging the ballast, and it's very noobish. i know people that have almost died from not taking electricity serious. use common sense. im not trying to be a dick but be professional. only use ballasts and bulbs of the exact wattage and hid type. they do make mh conversion bulbs for use in hps ballast though which are fine as long as the wattage is the same.

johnny961 said:

Why would u not buy the right bulb? No matter whether u got the fixture for free or whatever the bulb is only about at the most 10$ Also a mh bulb will not light properly in a hps ballast & vice versa. DONT take shortcuts & always be prepared to live life as u see fit.

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For starters, now-a-days they have ballasts that are switchable MH/HPS so no need for expensive conversion bulbs, either MH>HPS or HPS>MH--use one ballast for veg and bloom. And I doubt you'll buy a 1000w bulb for $10, closer to $100.

A great reason for using a smaller bulb is for economy & energy conservation--you get a double savings as smaller bulbs are cheaper and will use less energy. Of course they won't produce the same amount of over-all Lumens but the Lumens the plants receive can be equal... here's how:

When your plants are just starting, they don't take up as much acreage and don't have much leaf surface area or leaves obscuring others so less light is needed, and by using say 400w MH on a 1000w ballast the light can be closer to the plants without burning while still covering the needed area, providing the same Lumens you'd get having a larger bulb positioned higher. As your plants get bushier, taking up more room and adding obscuring leaves, switch to 600w MH and raise its height to plants. Then when you go to bloom, switch to 1000w HPS and raise its height to plants even more.

You save electricity (more on that later) and the cost of a much more expensive bulb but still giving the plants what they need. While the 600w cost will exceed that of the 400w, the lives of both will double. You might also get by without need for lamp cooling while using the smaller bulbs. To me it's a win, win, win situation.

Is using a smaller bulb dangerous, gonna burn your house down? NO. I say this with decades of experience as an electrician at a very large electric power plant with 10s of 1000s of lights, HPS, MH, MV, LPS, quartz, florescent, incandescent, you name it. Using smaller HPS/MH/MV bulbs never caused any safety, operation, or longevity issues. It will not overheat the ballast, just the opposite, but it won't give you quite the energy savings, i.e. you won't get a 600w savings using a 400w bulb on a 1000w ballast--it will be fairly close but there will be more internal loss on the 1000w ballast than a 400w ballast. Typical ballast losses run 15% (there are higher and lower efficiency ballasts, the difference being in price)--the difference between losses will only be a portion of this 15% so as you see there will still be plenty of savings.