My 400 Watt Nanolux ballast can go down to 50 percent power for MH and HPS, but What If I tried to run a 175 Watt MV on it? Will 25 Watts be enough to destroy the lamp?
The fake 175 Watt (but really 125) lamps are overdriven by 50 Watts on a 175 Watt ballast.
I would use my cheap Chinese clear 175 Watt MV lamp for this. I don't want to risk a Moon Pulse lamp.

MV's are rather tolerant to the feed current variation, but just because as an unsaturated vapor concept, they keep the arc voltage constant, so  real power is just linearly proportional to the feed current, without any thermal positive feedback or so (as e.g. with HPS).
Usually for a short time they can tolerate overloads of factor of two or so. There are known cases, where a 250W lamp was more than the rated life in a 400W fixture and no one spot the problem until the scheduled relamping (they were surprised by finding a bit bulged arctube and so spot the error made years ago)

What does the "can go down to 50% power" means? What is the load characteristic on that setting? Does it feed the 130V arc by the required 1.5A?
Most ballasts behave more like a constant current source, so the power depends strongly on the arc voltage. That is the main reason, why just the power rating is by far not enough information to judge if the ballast will be suitable or not.

And how do you came to the conclusion of "fake 175W lamps"? The fact modern lamps use smaller arc tubes does not mean any fake lamps or so. The main reason for a smaller arc tube is to boost the arc loading, so the efficacy. The rating is by far not only the arctube size (pulse MH's have way smaller arctube for the same power, yet it is made of the same materials). What matters is the electrode size and the overall thermal management of the lamp. Usually the higher loading of the smaller arctubes is balanced out by the higher outer bulb fill pressure. So although the arctube may be smaller, it is not overloaded on the rated power.

The true lamp specs are Voltage/Current. That is, there maybe lamps with same power but different Voltage/Current, like S55 and S56 HPS. Both are 150W, but using one on the wrong ballast will definitely lead to it working at some other power greatly different than 150W (if it starts at all)

The same goes for apparently same power rating Pulse vs Probe lamps. Their Voltage/Current specs are different

As that ballast is most likely intended for Pulse Start lamps, we dont even know what power it would deliver into a Probe Start lamp in the 1st place (not because of the Probe starting, but because the lamp Voltage/Current specs are different), whether at full or half power



The Voltage of HPS (and to lower extent some MH too) goes down when temperature goes down. So the voltage allready account for part of the power drop when HPS is dimmed. So to drop the ovreall power by 1/2, the current alone does not have to be down to 1/2, it is still higher

Unlike HPS, This effect is very slight in Mercury lamps, so the Voltage is not changing much. When the current is not changed by 1/2, the lamp power won't change by 1/2 either, it'll stay closer to full power than intended



Last, who knows how exactly really is the "1/2 power" setting putting out 1/2 power. Maybe they mean 1/2 Lumens, so more like 2/3's power to the lamp ? Maybe its simply inexact ?



The lamp power will be lower than 400W i think, but i dont know by what extent. It is probably not going to blow out the lamp at once, so you'd be able to power it up and measure the arc current, as long as it is Magnetic ballast (Electronic may put out a wave shape or frequency that basic multimeters may not be able to correctly work at), and see how close it is to what's wanted

I'll probably just try doing this if the MV lamp looks to more resilient to arcs.

Some overdriving can be handled, unless it is a cheap lamp with everything on the edge (Especially electrode size). Mercury lamps also handle relatively well underdriving

But it is not only the lamp that can be harmed. The ballast too can overheat if the lamp arc voltage is too low, which makes it pass higher current. Same there, the ballast won't be damaged from an experiment, but in long term use (months, years) the overheating may cause isolation materials to go brittle and the like

Also, what type of ballasts and lamps ? US-types or Euro-types ?

Some overdriving can be handled, unless it is a cheap lamp with everything on the edge (Especially electrode size). Mercury lamps also handle relatively well underdriving

But it is not only the lamp that can be harmed. The ballast too can overheat if the lamp arc voltage is too low, which makes it pass higher current. Same there, the ballast won't be damaged from an experiment, but in long term use (months, years) the overheating may cause isolation materials to go brittle and the like

Also, what type of ballasts and lamps ? US-types or Euro-types ?

The ballast I'm using is a Nanolux electronic ballast, with forced air cooling!
It's really tiny and rated for driving 400 Watt lamps.
It has 75, 50, and 110 percent driving modes.
They are very vague with how it actually dims.

Update: I will just try the 175 Watt MV out with my Lumatek ballast. I know it's wattage (250) and has been tested with MV before without any arcing.

Update: I tested it out, and it worked!
No dangerous arcing. I finally know what MV looks like. It makes red things like fire extinguishers turn into a dark burgundy color, floors turn green, and your skin look like a zombie.

Yep. It's a lovely and unique light. I like it.

Then why ban it?

MERCURY!!!! scared ?

MERCURY!!!! scared ?

Why not ban Fluorescent, Metal Halide, HPS, or Induction?

They dont contain Mercury in the name, so are not supposed to be filled to the top with liquid Mercury, are they ?

They dont contain Mercury in the name, so are not supposed to be filled to the top with liquid Mercury, are they ?

Nope. MV also isn't filled to the top with Mercury.
How about we call it High Pressure Discharge to soften up the name?
I also noticed while running it that you could see high amounts of detail, and was easy on the eyes. With my laser glasses, it looked like a greenish orange.

That is for the most part the 1st half of the logic of lamp bans. The other half is, ban everything that is too well performing for its cost in general (non Rough Service Incandescents, non Deluxe /D and /CW Fluorescents, and so on)

That is one of the benefits of Mercury lamps. They dont put out a lot of Lumens (compared to more advanced HIDs and to FL), but their light provides excellent vision even with quite limited brightness. So they are very good choice to provide oudoor light without it being bright to affect nature or dark sky, and without glare even from very basic optics

It could make quite a good indoor night light, if it could be miniaturized enough.