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Re: IceCap Ballasts -- What's the watts or who's on first

Scott wrote:

For years the mystery of mysteries in reef keeping was "How the heck do
IceCap electronic ballasts work with so many different kinds and sizes
of bulbs?"  Sometimes, folks supposed that the IceCap has some special
brain function that learned what bulbs were connected to it --
electronic engineers often refer to this type of flourescent ballast
circuit as "hee hee hee," which is EE shorthand for

Eventually, it came out that IceCaps overdrive lamps rated for higher
wattages and underdrove those rated for lower wattages.  Being
electronic (operating at a much higher frequency), you still got more
light (or maybe about as much) light from a large high wattage bulb
than from a more conventional magnetic (a.k.a. tar) ballast.

But what I never came across was any listing of the watts for IceCaps
with different combinations of bulbs.  A few values have been
published.  Four 110-watt-rated VHO bulbs get 230 watts out of an
IceCap.  I think a pair of 75 watt VHOs get something over 200 also.

Anyone find what I never did?  More of the values for IceCap outputs?

I am not sure I am understanding the question. Do you mean how much does
the ballast draw with those lamps? I have tried asking Icecap a couple
of times about ballast factors but they don't answer. I don't think that
the wattage drawn by the lamps or the wattage drawn by the ballast is
nearly as important as the ballast factor with the various lamp
combinations. I know it is a lot to ask as there are so many
possibilities but they could at least give the factors for a few common
combinations. Without the B.F. no accurate prediction of light level can
be made. You could just measure how much the ballast draws or the
voltage and amperage across each lamp and just assume the lamp
efficiency didn't drop a whole lot if you wanted a rough answer. You
probably need a pretty sophisticated true RMS meter capable of measuring
 high frequencies. The wattage a lamp draws is partly a result of the
diameter and length of lamp. 4 2 footers in parallel appear to draw
about 1/2 as much as 4 4 footers of the same diameter. Two 2 footers
should in series should draw about the same a 1 4 footer. Changing the
number of lamp circuits seems to actually slightly increase the draw on
the remaining circuits.

It appears to me that Icecap is not really unique in any way. Any
electronic ballast exhibits the same ability to drive a very large
combination of lamps. As long as you do not try to run a lamp below the
current required to ignite and run the lamp and as long as you do not
overdrive the lamp to such an extent that it destroys it you are OK. The
more you overdrive the less efficient the lamp will operate and the
sooner it will fail. There are sign ballasts that are virtually
identical in specification to Icecap ballasts. There are even sign
ballasts that are much larger than Icecap Ballasts. I suspect that lamps
driven in this way are not always being driven in the most efficient
possible way. There has to be a trade off between versatility and
efficiency. Otherwise why not just drive all lamps with the same