VHO ballast

ok so i just bought a ballast ..

http://www.utahreefs.com/forum/forum_posts.asp?TID=10190& ;PN=1


it will fire 2 6' or 2 8' bulbs... so does that mean it could also fire 4 4' bulbs???? or only 2 4' bulbs??


right now my icecap 430 is running 3 bulbs... i want to run actinic only on that one and 4 daylight bulbs with this one... will that work??? otherwise i guess ill only be running 2 actinics on the new ballast  and 3 daylight bulbs on the icecap ballast ...



any ideas??? any ideas on how to wire it to run 4 4' bulbs??? id imagine if it can run 2 8' bulbs it should be able to do 4 4' bulbs... 16' of total bulb length.. right??

From the diagram I would say that it will only support 2 bulbs.  But you should be able to locate the specific details based on the model on line.  Also you might want to contact the person you purchased it from.

i know i will get some drop in voltage because there will now be 2 more resistances in the chain than before... but i will be running 48 watt bulbs instaed of actual VHO bulbs... (thats what im doing now and it works fine) so the bulbs should not require much to fire....



btw ... anybody that actually spends the money on VHO bulbs is crazy.. NO bulbs work just fine and last almost as long..

jfinch wrote: That's a rapid start ballast so it might work and it might not.  You'll just have to try it to see.  If the bulbs start, you'll be ok, imo.  The hard part is starting the bulbs.  If the ballast was an instant start ballast (like the Fulhams) then I'd say you wouldn't have any problem doing it.  I've done it many times without incident. anybody that actually spends the money on VHO bulbs is crazy.. NO bulbs work just fine and last almost as long.. The extra $3/bulb is worth it to get the VHO starting coils, imo.

i think that starting it shoudl be fairly easy as well.... just because ill be using NO bulbs compared to VHO... the wattage required to power em is about half... coarse i dunno how they work and if the wattage would have anything at all to do with it..

they are only 3 dollars more??? wow.. i didnt know that... most LFS's list em at around 40 while you can get NO bulbs for around 20...


BTW.... hagan NO bulbs, marine glo and power glow look REALLY nice in a VHO ballast... thast what i use and my SPS is doing VERY well and my acanstrea all look amazing.. i think the power glow is a 18k bulb.. nice and whitish purple...

does my wiring diagram look ok and make sense??? id imagine if i do those ones in series with the others how they are it should work just fine... if it can start the bulbs... look ok to you??? 

jfinch wrote: Yes it makes sense to me.  But shorten the wire connecting the two adjacent bulbs together, don't wire it exactly like you have drawn.  Wire the same ends of the two bulbs together (only take about 4" of wire) and then wire the ballast wires all on the same sides.  It's the same wiring scheme, just uses less (less resistance) wire.  Hope this makes sense. I have my doubts that you'll be able to start the bulbs up, but please do try.  It will be good info either way.

yeah i guess your right :) i could do it that way :P

worst case it will fry the bulbs, it should work, the thing that I am concered about is the starting current may not be correct for 2x the filiment current.(2 extra bulbs)

I.E. 2 vho bulbs will have 4 filiments to preheat for start, your setup will have 8 filliments to preheat before start( lighting ), I fear that with your wiring, the first two bulbs(1a 2a) are going to get all of the amperage needed to start two f96 bulbs and the N.O. filiments are not going to be able to handle that.

either way the balast should be fine for the trial, so i'd recomend using old bulbs for the trial.
  vho bulbs run at a higher milivolt than a N.O. bulb, a vho bulb will fire a N.O. bulb but at a higher milivolt, end result, shorter lamp life for the bulb, now where with a saltwater tank one year and there gone, may/maynot not be a problem.

one thing that I came across with doing this trick with n.o. bulbs and WAY stronger balasts was the stronger wattage balast forced a color shift in the bulb.


Brian 


Edited by bbeck4x4

according to this website what I drew up wont work, but read for yourself.



Brian


http://members.misty.com/don/f-lamp.html#wd5

It might help you if you knew how a fluorescent ballast works.  Once the bulb(s) is lit, all the ballast does is regulate the current (not voltage) through the bulbs.  When a bulb is lit there is a plasma arc that travels from one electrode on one end of the bulb to the other electrode on the other end.  There is zero resistance in this arc, so without regulating the current the circuit would be short circuited and over amp, burning out the lamp.  Inside the ballast is a coil of wire that acts as a current "choke" that limits the current through the circuit.  Normal output ballast limit this to about 400 milliamps per lamp while VHO ballasts limit to 1200-1500 milliamps per lamp.  In a nutshell, that is how a ballast works.  The differences in ballasts are in how they start the lamp.  The two most common methods are Rapid Start and Instant Start.

Rapid Start:  There is a small current that is always flowing (or flows just before turning on) from the ballast, through the electrode at one end of the bulb through a "starter", through the electrode at the other end of the bulb and back to the ballast.  This heats up the filaments in the electrode and allows the arc to strike at a lower then otherwise needed voltage.  Some ballasts require an external "starter" (that little aluminum cylinder that you see in some light fixtures) while others have them "built in".  So, once the filaments are warm the ballast applies a voltage (250 - 350 volts) to initiate the arc.  Once the bulb is lit, the voltage drops down to around 100 - 200 volts to maintain the arc.

Instant Start:  There are no warming currents.  This ballast just blasts the lamp with a very high voltage (600 volts) and starts the arc via brute force.  Once the bulb is lit the voltage drops down to 100 - 200 volts and operates the same way every other ballast works.

So, with that knowledge in hand, you can see why I'm skeptical that you can series bulbs together using a rapid start ballast.  You'll only be heating one element on each bulb... not sure that's enough to strike the lamp.  And you can see why running bulbs in series is easier with an instant start ballast.  The voltage is easily transferred through the wire connecting the ends of the bulbs together.

If you wire them the way bbeck4x4 shows in his drawing, you'll be warming each of the filaments but the ballast will be regulating full vho current (1500 mA) to be split between two bulbs, so the bulbs will not be operating at VHO output, but somewhere between NO and HO.  Also there is no guarantee that both bulbs will light up at the same time.  You might have one of the bulbs not light up. 

And finally, none of this "bulbs in series" is approved or sanctioned by any ballast manufacturer.  Do at your own risk.

good description jon, back when I took the NALMCO test (interNational Association of Lighting Management Companies) I could have given that description.

lostcause,
Myself, I would use the balast the way it was intended, but I'm getting lazy and "just want it to work"(TM)(on the first try)
     if you want to fire four bulbs buy or get a balast/balasts intended for that purpose, less fire risk that way.(I have a few myself floating around, 4 lamp t8f32 electronic ballasts) I don't believe that a few minute test would harm the balast, it would either work or not. the risk is if the balast frys one or more of the bulbs. 

the balast for what you are trying would be better if it were an "instant start" but look, used the way it was intended, you get two vho lamps running at max power for the bulb and the best light quality and lamp life for the bulbs.

hope that helps.

Brian