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Re: Metal Halides In Australia

On Tue, Dec 03, 2002 at 12:40:46PM -0500, Bill Wichers
<billw at waveform_net> wrote:

> Arg, forgot about that heat question in there... The MH core+coil 
> (synonymous with big+heavy :-) ballasts are usually about 80% efficient if 
> you go with the nameplate load numbers and the wattage on the bulb. For a 
> 175w ballast then you're going to be putting out about 35 watts of heat 
> *from the ballast alone*. Yes, the ballast will get HOT. I just complete a 
> new 3x175w ballast system and the ballasts get too hot to touch (the core 
> itself, not the enclosure it's mounted in), and I have them mounted to 
> allow maximum convection cooling *all* the way around each ballast. In 
> normal operation this isn't really a problem since the metal case doesn't 
> care about the heat, and the ballasts are built to tolerate the heat they 
> produce. The electronic ballasts are supposed to run cooler but I haven't 
> played with any myself.
> You'll want a remote ballast, which is pretty typical for aquarium MH 
> lights. The ballast will be heavy and fairly large, and you'll want to be 
> able to put it away from the hood.
> The reward you get is the best lighting on the market for aquariums, IMHO 
> :-) I'm big fan of MH lighting.

The 150W electronic ballast I have (Osram) gets barely warm, far
from being hot. If at all possible, I'll suggest electronic ballasts
over tar ones. One thing you mentioned is efficiency, the other one
is supposedly longer life of MH bulbs. Osram claims increase of ~50%
for HQI bulbs (quartz arc tube) and lower CRI drift, for HCI bulbs
(ceramic arc tube) ~30%. I'm also fan of MH lighting and with
>= 90lm/W it's side-by-side with fluorescent efficiency wise (T8).
Go MH, it's superior lighting :-)

Vallo Kallaste
kalts at estpak_ee