I just did way too much reading into fluorescents and I've come to the conclusion that either some vital piece of information is missing (ie. my understanding of the physics), or else a lot of the information on the 'net is faulty.
I finally lugged home some 48" T5 tubes to stick into my WH7.. I talked to a big lighting guy at our store (a customer who's really into reefs) and he gave me the spiel about how things work...
... they don't work that way.
I was told that to "overdrive" a standard (let's say a 40W 48" standard T12 bulb for simplicity), you connect two of the RED leads together and then feed them into the ballast. Then instead of having the 54W available along the circuit, the bulb has 108W available, and you'll be running at HO.
I finally got into a big argument with my dad about it and as usual I was wrong. Experimented and proven wrong again.
How fluorescent lighting works, according to someone who seems to know more than I:
A ballast rated at 54W will be able to drive a 54W bulb and nothing stronger. If you put a 60W bulb in there, it will probably work but you'll get a lot of heat generated in the ballast itself and ultimately fry it.
When you close the switch in a fluorescent ballast/lamp circuit, the coil in the ballast generates a field. In a magnetic ballast you will have a starter which will occasionally trigger and close the entire circuit, causing power to move, and the magnetic field to collapse. The collapse of the field pumps a high voltage into the circuit (electronic ballasts generate this high voltage using a different principle, afaik
, but the end result is the same).
The high voltage now goes into the lamp (the starter is opened again) and if the voltage is high enough, the electrons in the bulb get excited to the point where they can flow "through" the bulb and excite the phosphors in the lamp's interior (that's the cool part - a totally clear fluorescent lamp will work just fine, except it will emit no light because the coating is the only thing producing the light). Once the juice is "flowing" through the bulb then the starter will no longer fire, since the bulb is now the path of least resistance. Now the bulb needs only the wattage it is rated at, and that's all it will take in a 120V power system (like North American house lines).
So what happens when you twist two of the WH7 wires together and then connect it? You get a 40W lamp that fires and then draws 40W... Period. End of story. A ballast will provide only as much power as the bulb needs to draw.
Case in point: I bought a 9W T5 from Rona (9" long tube just to test out) and hooked it up to the WH7. That's one 54W lead running into a 9W bulb. What happened? The bulb fired and lit normally. The bulb needs 9W, so it takes 9W. The other 45W that is available along that lead is basically wasted.
Why twist those wires together at all, then? If you have a HO bulb, or some bulb that draws 110W or so, then you obviously need two of the leads. If you have anything up to 54W, you just need the one and you're fine. It makes sense and there's no real magic there.
So back to my T5s now. I wired her up normally and fired her up. Bling! A T5 bulb shining in my basement. Ok, fine. Let's try double leads like was suggested. Bling! A T5 bulb shining in my basement again! No higher output - though I should probably stick a meter on it just to say I did. The visible intensity was absolutely the same, however, and the physics as I understand them dictate that the bulb won't take any more power regardless.
Then I thought, "what if I stick EIGHT T5s on this ballast instead of just four?" The WH7, after all, is rated for 4X54W and each T5 is 28W - I could pair them off and have two bulbs to each wire.
Tried that. Hooking the bulbs up in parallel gave me the result I should have expected... One bulb has a slightly lower resistance inside it, and so it fires first. Now that the firing bulb has minimal resistance, the second bulb has no way to fire. Again, you have 28W going through one bulb. A workaround here is to wire starters up to EACH bulb and let it work that way, though I don't know that this would work with electronic ballasts - I don't understand the technology that well.
What about connecting them in series? I didn't try, but I believe you require a 220/240 volt ballast to then fire those - double voltage to get across that big expanse.
I saw some 340V electronic ballasts at Home Depot for 20 bucks (used).. Almost tempted to take one home and play with it, but I can see where this might go... :twisted:
So where does this leave me? Well, for one, I'm still building my T5 NO light fixture and I'm going to post up my plans/pics when it's done for comments. So far I like the way it's shaping up.
As for HO: I guess I could either pick up some HO bulbs that will work, or else do some fancy footwork to make the lamps take more current. P=IV (Watts=Amps*Volts), so I suppose you could force the power driving into the bulb by inflating the current or voltage.. Haven't a clue how to do that easily or safely at the moment.
That's all I got. I welcome any comments as I still don't feel comfortable about the theory surrounding this stuff.
(Edit: Sam actually filled a few holes in my theory in here
. Any chance you could elaborate on what is physically happening when you hook up the bulbs in series, Sam?)