Fluorescent light without ballast??

[sfsuphysics]

What exactly is a ballast? Is it a fancy name for a transformer that coverts the AC to DC? I know some of them "warm up" the bulb or provide "instant on" or something, but is it really necessary? I ask this because I'm thinking of wiring up some lights, and noticed one of my old tanks I used for FW has a light hood without a ballast, but it does have one of those fat transformer plugs.

So does anyone have any thoughts on the matter? Is it really necessary?

Thanks.

[H20ENG]

The ballast is a transformer which steps up the voltage to about 600v. The electronic ballasts use a pulse to start the lamp while older ballasts use a starter to give the lamp a full voltage start, then open to run the lamp.

[mjw357]

it also limits the current, yes they are absolutely necessary.

[sfsuphysics]

So I assume the ballast is the priciest part of any DIY setup? In which case how much do they go for? I see lighting hoods cost upwards of $500 for something not terribly complicated, I'm just wondering where all the cost is distributed.

[mjw357]

yes, especially the IceCap type electronic ballasts. then you have reflectors and endcaps, wiring and assorted hardware, labor to put it together and test. On some of the really nice German hoods you are paying a lot for the aluminum housing.

[thedogofwar]

Different types of lights require different ballasts. There are also different materials used to make ballasts for each application.

If you're interested in HO or VHO I recommend Fulham's Workhorse series. They are great ballasts at a fair price.

My DIY 150W VHO set-up ran me $110 for everything excluding any canopy.

[sfsuphysics]

Well having checked out homedepot today, the only thing they have are the 4 light t8 ballasts but they're for the 32W versions, not HO ones (not that they sell the bulbs their though).

Which leads me to ask, every lighting faq i've seen says "you should have 3-5 watts per gallon, or whatnot, well a T8 light that uses 32W puts out more light than a T12 light that uses 40W, so what sort of general rule of thumb is there for lumens?

[mjw357]

that rule of thumb is just that, very general. especially now when we have so many choices in flourescent lighting; NO, HO, VHO, PC, T-8, T-5 etc. as well as all the different ballast options.

your best bet is to start by deciding what you want to keep in your tank , soft corals, clams and design the lighting around that.

find out what other people with your tank size and the same kind of animals are using and let that be a guide.

[sfsuphysics]

Well see, I really dont care much about the super bright creatures like corals, atleast not for a long while. So I might go the NO route (with the LED supplimenting as well *grin*).

I think I'd like a bubble tip in there, and that'll probably be the most light intensive creature (well, not including any hitchhikers on my liverock).

Anyways, thanks for the input. Now if I can just get fricking home depot or lowes to have the 6500k "daylight plus" 18" - 24" t5's I'll be in business and get started with my light hood! They always seem to only have the "warm white" or "full spectrum" (5000k) lights.

[Little Reefer Boy]

Originally posted by sfsuphysics
I ask this because I'm thinking of wiring up some lights, and noticed one of my old tanks I used for FW has a light hood without a ballast, but it does have one of those fat transformer plugs.

Just so you know....

If you gutted out that old light hood, I'm sure you'll actually find a small ballast or two hidden in it. It will be sandwiched between the outer shell and the inner shell. The "fat transformer plug" that you're describing is probably just the starter.

[sfsuphysics]

Originally posted by Little Reefer Boy
Just so you know....

If you gutted out that old light hood, I'm sure you'll actually find a small ballast or two hidden in it. It will be sandwiched between the outer shell and the inner shell. The "fat transformer plug" that you're describing is probably just the starter.

Well I gutted the thing, and the only thing is wires from the ends of the tubes to switch that turns it on. Its not a starter because for that light I have to hold in the power switch for a couple seconds to start it up.

[mjw357]

the wall plug is the ballast, it's just a preheat type.