OVERDRIVEN MetalHalide

[DEC6]

Does anyone know if it is possible to over-drive a metal halide bulb i.e. use a 175 bulb in a 250 ballast. The ballasts are electronic so would they just output the amount of power/correct for, the 175 bulb or coould you truley over drive it? If you can overdrive them, what would the effect be? (i.e. light color wise and effect on the ballast and bulb)

 

[james-lee]

I wouldnt do it what if the bulb explodes? Better to just get the right wattage bulb and be safe than sorry. As far as using a lesser wattage bulbs on a higher wattage ballast I think only if the ballast says it can handle say 250 and 400 if its doesnt it wont run.

 

[DEC6]

:dontknow: Well, I have been doing it to the same bulb for over a year now. I don't really have anything to measure the out put (LUX?) but the light it gives off is very white (I think it is either a 10K or 14K bulb but I will have to check) and the bulb has not seemed to have gotten any dimmer over time. I am just raising softies and LPS so they might not notice a change in light over the year but they are all doing great. Also this was not a new bulb. It was in a 175W fixture that I bought and the guy said it was about 6 mo old already. I just stuck it in my 250W fixture for "fun" but I am thinking this might be a great way to extend the life of a bulb. Any ideas about what is going on with this bulb?

 

[DEC6]

As far as using a lesser wattage bulbs on a higher wattage ballast I think only if the ballast says it can handle say 250 and 400 if its doesnt it wont run.

Well that is what I am wondering. Is it because it is an electronic ballast (the 250W) does it automatically just drive it at 175W or is it overdriving it giving it a longer life and a whiter light?

 

[james-lee]

Well the bulb could be whitish due to it being under driven. Being electronic it could work but I am not 100% sure. Who is the mfg? Either email them or try and google to see if anyone has doen this with that type of ballast.

 

[toomuch420]

first off mh bulbs only last 6 to 12 months any longer use is a waste of $.
you will not notice a differance visually but bet your corals will notice.as far as your ? Idk. But buy right wattage bulbs since you are way over due 4 new ones anyways.

 

[Reefer08]

NO! You can't overdrive them. Some newer ballasts have an overdrive feature that pushes the bulb 10% greater than what they're rated for. Aside from that you shout not attempt a 175w bulb in a 250w ballast.

 

[DEC6]

I read somewhere that you could overdrive fluorescent bulbs by doubling up on the wiring (this was a while ago so I can't remember exactly) i.e. hooking two sets of wires to the pegs which if I am not mistaken would make it 240V rather than 120V. How would this be any different. You are just passing more energy through the gas in the tube and making it fluoresce even more.

And what makes a bulb wear out? It is probably not the gas itself in the bulb wearing out as the electrons just keep jumping valencies and falling back.

 

[Reefer08]

Metal halide bulbs are different from fluorescent bulbs. I think if you attempted to overdrive the bulb that much it would actually blow. But try it and let us know what happens LOL. But we warned you not too.

 

[DEC6]

That is what I have been doing for over a year now. I am running a 175W bulb (Sun Day MH-175W Blue) in 250W electronic ballasts (Reef Fanatic RF250EB). But I don't know if e-ballast automatically compensate and only drive it at 175W or if it is truly being "over driven" and as far as I can tell the light still looks great. I mentioned above that it was very white light. It is actually somewhat blue but in combination with 65K florescents I also have it gives a very nice white color.

 

[bullitr]

I overdriven all my bulb before to 300 watts on 250 watts bulb The 20 k looks 16k but 175 watts to 250 watts That's way to big of a jump .

 

[IEreefmaster]

Well, I think there are a couple issues here. You might run in to heat issues, to which the glass casing may not be able to handle? The physical bulb may not be able to take that much current passing through it....etc etc...

 

[DEC6]

....or....and this is what I think is probably happening, the electronic ballasts somehow know what sort of bulb is in there and only puts out a certain amount of power. I don't think I have heat issues as it is mounted 4-6 inches above my tank and I have not melted the top or anything (plexi). I do have fans at each end of the canopy.

Thx bullitr. I was thinking what you posted, that I am getting more light from a smaller bulb but not as blue, which is OK. How did you overdrive to 300W (that would be about 20%), are your ballasts adjustable output?

 

[Puffalicious]

my 250w radiums operates at around ~370-400F degrees and it does melt plastic stuff I put near it .... Yea I was bored and I used my IR thermometer to check, lol