# CF Lighting - AHS, bulb wattage compatibility



## hoppycalif (Apr 7, 2005)

I keep reading here that one can use 65 watt bulbs in a 55 watt fixture, same ballast, with no problems. And, I asked AHS if I could install 36 watt bulbs in a 55 watt fixture - also no problem. So, I am confused.

What happens when we put a different watt bulb in a fixture - does the ballast recognize the bulb wattage and adjust accordingly? Does the higher wattage bulb operate at the lower wattage? Does the lower watt bulb just get overdriven? And, how far can one take this - for example, can you put a 96 watt bulb in a 36 watt fixture, assuming you had that much room, and have it work right? How about if you use two different wattage bulbs with a dual bulb ballast?


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## John N. (Dec 11, 2005)

*Re: CF Lighting-AHS,etc*

I'm no expert, however I understand it as this:

The fixture's ballast regulates the flow of energy into the CF bulb/lamp. The output of the CF bulb is dependent on the ballast maximum output. _For example, _

A 55w bulb paired with a ballast capable for a 96w bulb will drive the bulb at 55w.
A 96w bulb paired with a ballast capable for a 55w will drive the bulb at 55w.

Therefore, the ballast controls the energy, and recognizes the CF bulb's maximum wattage and powers it as such.

-John N.


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## hoppycalif (Apr 7, 2005)

*Re: CF Lighting-AHS,etc*

I have 36 watt bulbs in my AHS 2X 55 watt kit, and I still have the 55 watt bulbs. (I'm sure you can see what's coming next!) So, can I put one 55 watt and one 36 watt bulb in it, and have 91 watts of light? Or does the ballast have to have equal wattage bulbs in it? I'm just too old to know how to answer this question - my expertise is in starting a fire with flint.


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## Gomer (Feb 2, 2004)

*Re: CF Lighting-AHS,etc*

http://www.fulham.com/pdf/FulhamCatalog_04.pdf

Scroll down to page 22. From there on, you'll see the tons and tons of bulb configurations that your ballast can run.


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## hoppycalif (Apr 7, 2005)

*Re: CF Lighting-AHS,etc*

Thank you Gomer. But, none of the configurations shown are two bulbs of different wattage. I have the Workhorse 5 ballast, which certainly can handle any combination of 36 and 55 watt bulbs, but is there a reason why both bulbs need to be the same wattage?


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## Left C (Jun 14, 2005)

*Re: CF Lighting-AHS,etc*

Hi Hoppy

The Workhorse 3 ballast comes with the 1x55w and the 1x36w kits. They are load sensitive and are rated for 64w max.

I hope this helps.

Left C


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## Gomer (Feb 2, 2004)

Instinct says they should be match, but I have run the ballasts with one leg completely open (unused) which may indicate independent rails allowing both types at once.


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## Squawkbert (Jan 3, 2007)

My best guess is that the ballast is setup to offer a certain voltage and that the current drawn (at that voltage) by a given bulb is a property of the bulb. The ballast is also setup to operate within a certain range of current output, so you end up with an assortment of bulb configurations that will work within the ballast's range of current outputs at a pretty well fixed voltage.

Wattage is just the product of current & voltage (with an exponent thrown in, right?).


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## hoppycalif (Apr 7, 2005)

A fluorescent light is sort of an electric arc device. That type of device is inherently unstable, so it needs a ballast in series to stabilize it - the balast is usually a resistor for a DC arc device, but an inductor for a AC arc device. That is how an old non-electronic or magnetic ballast works. The idea is as the "arc" fluctuates in length it's voltage varies, but the ballast acts to keep enough voltage available to keep the arc from extinguishing. Now, an electronic ballast is a different device, but it, too, has to provide a variable voltage to maintain the "arc" in the bulb. So, the wattage will be the combined wattage of the bulb plus the power lost to the ballast. I used to work with electric arc devices about 40 years ago, so this is what I remember.

I guess I will just have to try my AHS light with a 55 and a 36 watt bulb to see what happens. I'm not sure yet that I want to increase the light that much, but I did want the option of doing it.


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