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Re: DIY Power Compacts

On Mon, 30 Nov 1998 IDMiamiBob at aol_com wrote:

> Mark Pan writes:
> 
> > 2 x Osram Dulux D, 1,700 lumens 6,000 K lights (now that's very, very
> >  white!)
> >  26Watts with rated output of 150W (!) Or so the box says so anyway :-)
> 
> Forgive me if I am wrong, but isn't a standard 40-watt Flourescent tube rated
> at like 3,120 lumens?  And Ultralumes give off even more than that.  If this
> is the case, I don't understand how a lamp with 1700 lumens ranks a rating of
> 150W, unless it is being compared to incandescents.  Then we are mixing apples
> and kumquats, and I fail to see the output advantage of PCs

First off, these aren't PC's.  These are the older 13 watt traditional
compact fluorescents that are equivalent in efficiency to standard
fluorescent tubes.  In fact, you use the same small tar ballast to drive
the 13W CF's that you use for 15, 18 and 20 watt tubes.  They also come in
9 watt tubes.

Secondly, yeah, this is now the second post in a week to talk about the
"equivalent wattage" as if it's being compared with regular fluorescents.  
"Rated output" doesn't mean squat on this list.  Talk lumens, talk PAR,
talk about actual wattage used by the bulbs.  Dulux tubes are 13 watt
fluorescent tubes.  Not 75 watts.  If you use the 2-bulb unit, you are
getting 26 watts of fluorescent light.  This is slightly more than a
2-foot T12, and probably similar to a 2' T-8.  You cannot replace a 175
watt MH pendant with this unit and expect similar output.

So what's the advantage of CF's?  They're tiny!  You can use them on
little tanks, or cram them into small areas in larger tanks (like that
omnipresent extra foot left over on a 100-gallon).  As Mark notes, you can
fit two of them in the space of a single 15 watt strip on top of a 10,
giving you almost twice the power.  I have a tiny hood that fits over a
2.5 gallon show tank that uses one of them.

The neat thing about "Power Compacts" is that they extend this concept to
larger tubes, such as the 22" long 40 watt tube I mentioned this morning.
And these later-generation tubes are supposed to have similar efficiency
to T-8's.

  - Erik

-- 
Erik Olson
erik at thekrib dot com