Well since i cant upload here, ill just post a message on the forums.

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Well here are some Pros and COns of both

MV:

Pros:
Nicer color
Lasts Longer
Brighter than incandescent.

Cons:
Not very efficent, least efficient HID.
Lacks red light from spectrum
Less lumens per watt.

Now HPS:

Pros:
Very efficient
Lots of Lumens Per watt
Second brightest HID. (under LPS)

Cons:
Not good color,
Dosent last as long.
Also, under this kind of light, Its hard to deteer color.a

Don't really mind HPS like some here do. The only thing I don't like is that they banned Mercs...

I like HPS too. i dont see anything wrong with HPS. MV and HPS have the same number of pros and cons.

Banning MV does annoy me, cause every lampo has its pros and cons, they just look at efficency, they dont care on the peoples tastes.

I dont like so much about HPS. in autumn( where I live, streetlights are not needed in summer) HPS is pretty okay even in smaller "home streets" but when snow comes, It will make me like much more in MV lights. I could even say that white light of mv will make snowy streets looks much more peaceful. thats maybe because I usually link white color to winter. I dont have anything against HPS, but I will hope that in my home street there is never gonna be HPS lights. One of few things I like in HPS is the cycling at the EOL.

The MV reliability is becoming their huge disadvantage: They are often kept running long years past their lifetime (so they dim-out severely) and then they are accused of "low efficacy". SON start cycling, so it's clear for everybody, then the lamp has to be replaced.

The MV reliability is becoming their huge disadvantage: They are often kept running long years past their lifetime (so they dim-out severely) and then they are accused of "low efficacy". SON start cycling, so it's clear for everybody, then the lamp has to be replaced.

Yes, exactly.

And its not only about lumens, MV has better visibility for the same lumens in my opinion.

Also, coated MV does not lack red spectrum.

P.S The least efficient HID is the high pressure xenon 

Mercury ballasts can be a problem too, they tend to die quicker than others....

Mercury ballasts can be a problem too, they tend to die quicker than others....

With EU-style serial reactors i do not have such experience, when talking about ballast itself. What was the issue was the old mercury lanterns issue - water coming in contact with the ballast, so the ballast rust and when the corrosion progressed too far, it overheats.
In contrast HPS ballasts die much more often, but my guess for rootcause are cycling lamps kept there too long.

The MV reliability is becoming their huge disadvantage: They are often kept running long years past their lifetime (so they dim-out severely) and then they are accused of "low efficacy". SON start cycling, so it's clear for everybody, then the lamp has to be replaced.

I have seen many industrial halls wich has old but still working MV highbay fixtures that have very dimm lamps in them and then at somepoint there will be usually installed fluorescent lamps to give more light because old fixtures are so inefficient and does not give enought light. They dont realize that those MV lamps need to be replaced even thought those still stays on. 

Edit: here is a good example http://www.lighting-gallery.net/gallery/displayimage.php?pos=-39154

What do you mean HPS doesn't last long? 24,000 hours isn't long enough?

What do you mean HPS doesn't last long? 24,000 hours isn't long enough?

Maybe in some lab with controlled conditions, but I want to see a sodium lamp last as long in real life.
On the contrary, mercury lamps can last several times their rated lifetime, they just get so dim that the light output is no longer usable (and then people think they are not efficient).

Maybe in some lab with controlled conditions, but I want to see a sodium lamp last as long in real life.
On the contrary, mercury lamps can last several times their rated lifetime, they just get so dim that the light output is no longer usable (and then people think they are not efficient).

The question is, how do you rate life of mercury lamps. Usually the MV rating is for 50% lumen loss, what is too much for their economic use, so you end-up with usable life being about 3/4 of their life rating, so about 18000 hours of usable life.
Don't forget, then in regular streetlight use the 24000 hour life is spent after only 3..4years of service.

And the HPS life is rated for 50% of lamps dead, while the "2% failure rate" (acceptable for streetlights, so interval for group relamping) is usually at 3/4 of rated life on good quality lamps, what mean again 18000hours of usable life.

The issue with TS Brno (you are most likely refering to) is, they do only spot relamping and mostly with huge delay. This is not as apparent on MV's, but it yield a lot of cycling HPS...

Also, HPS can be used to grow plants. I'm sure A high Color temp coated merc could germinate and get the plants through the vegetative state. The HPS gets the plants up into flowering and fruiting.

I like BOTH-can live with either.For streetlighting feel the HPS is better for foggy areas.Their amber light cuts thru the fog.For reliability I find both are about equal.Same with life.In either light the bulbs are often run long after their useful life-so the efficiency goes down.HPS is used by growers for flowering-mercury (clear) for building outside lighting and tree areas.And retrofit MH conversion bulbs can be used with HPS and standard probe start MH works with mercury ballasts.

i too like both

As for reliability..

Some lanterns really tend to leak water in, adn will completely destroy the gear every few years. Otherwise the gear can last for ages....

I see a lot of mercury lanterns working with their original 60s/70s/80s ballast. They get replaced when the maintenance decide to put in a new lamp type, while they still work

I see a lot of HPS gear that is still original from the 80s and 90s, including electronic ignitors and all. In lamps, i seen HPS that did nearly 20 years before they started cycling. When they start, the cycling is very slow, in the beginning it goes off once in an hour or more, in the end, it is mostly off and only lights in clear mercury color once in a while

HPS gear reliability varies. Some gear does indeed fail, some other is the best.. In 2007 i seen a HPS floodlight that was installed and connected to power (full night) in 1995, and never fitted with a lamp. In 2007 you could still hear the ignitor trying to start the lamp after 12 years