Re: [APD] 20 watt bulbs where min 25 watt go

["S. Hieber" <shieber at yahoo_com>]

It's hard to say what a ballast with do with a particular
bulb that it is not designed for.  The watts that go
through the bulb will be a function of how the bulb and
ballast interact.  Sowhat the ballast does depends on the
bulb and vice versa. But it will probably put more than 20
watts through each bulb. Otoh, as you can see from your
ballasts, bulbs and ballasts are made to cover a whide
range (50-80 wattrated bulbs for these ballasts). It's
unlikely that it drives the longest bulbs at 80 watts or
the shortest bulbs at 50 watts. 

If you can find bulbs cheaply enough to potentially
sacrifice one or two, it might be worth a try -- they might
not light but if they do, the worst that will happen is
that the bulb ends will blacken very quickly and the lamp
fail (fail to light) after a short life (and run hotter
than normal).  Since the ballasts's rated for 2-25 watt
bulbs, why not use a pair of those? The diff in brightness,
compared to a pair of overdriven 20 watt bulbs might be
rather small.

If the shop light has one ballast for each bulb, then
putting two 20 bulbs in series on one ballast might work
better than putting one 20 watt bulb on each ballast.

good luck,
Scott H.
--- "Candy M." <cry_little_sister at hotmail_com> wrote:
> I have read various posts on overdriving lights, I have a
> question that may 
> fall down that line...
> I have a 29 gallon 30 inch long tank that I need to make
> lights for. 
> Currently there is a 4ft shop light hanging over it with
> 2 40 watt sunshine 
> bulbs. I have a canopy designed that would allow either
> removing the very 
> top section to allow the use of the shop light as is or
> optionally a plywood 
> piece that will sit into a 1/4 inch inset at the top.
> Figured this way I 
> could use the closed canopy or remove the top totally and
> have it as open 
> and depend on hanging lights.
> 
> My question is this:
> The ballast in these cheap walmart shop lights are
> designed to run " 2- 25, 
> 35 or 40 watt T12 bulbs"
> If I gut a couple and use the ballast and endcaps and use
> 2-24" bulbs it 
> would be putting 20 watt bulbs in it. Since it is not
> rated for 20 watt 
> bulbs would this be a bad idea? Would the 5 watts
> difference really make 
> that much difference especially safety wise?
> 


=====
S. Hieber

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