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Aquarist Forums => Equipment / DIY => Topic started by: RoxyDog on February 18, 2011, 08:50:46 PM

Title: Using lower watt bulbs than ballast can take - what happens?
Post by: RoxyDog on February 18, 2011, 08:50:46 PM
Hey all you lighting experts!  If you have a ballast system than runs 2 x 40w bulbs but you only use 2 x 20w bulbs in it, will it hurt the ballast in any way?  I would think it would be fine but really have no idea...
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: CanadaReef on February 18, 2011, 09:19:48 PM
What ballast are you using?
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: RoxyDog on February 18, 2011, 09:42:31 PM
A Hagen T8 ballast system (hope that's useful).
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: redbelly on February 19, 2011, 09:38:52 AM
You will be overdriving the bulbs.
They will burn bright for a much shorter period of time.
How much shorter can vary greatly from bulb to bulb.
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: rush on February 19, 2011, 10:19:27 AM
why are you running lower wattage bulbs?
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: RoxyDog on February 19, 2011, 01:28:48 PM
B/c the tank isn't long enough to fit 40w bulbs over it.
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: JetJumper on February 19, 2011, 02:32:27 PM
Quote from: RoxyDog on February 19, 2011, 01:28:48 PM
B/c the tank isn't long enough to fit 40w bulbs over it.

Can you fit 4x20watt?  If so then just run that and your bulbs will be fine and not overdriven :)

Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: RoxyDog on February 19, 2011, 02:58:00 PM
No, the ballast only has end caps for 2 bulbs.
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: JetJumper on February 19, 2011, 03:47:39 PM
Quote from: RoxyDog on February 19, 2011, 02:58:00 PM
No, the ballast only has end caps for 2 bulbs.

Modify it to work?  No reason why you shouldn't be able to do that.
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: RoxyDog on February 20, 2011, 08:08:03 AM
Also, I don't want 80w worth of light over the tank.  :)  Anyone know if overdriving the bulbs is unsafe in any way?
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: bitterman on February 20, 2011, 08:51:08 AM
Overdriving bulbs will most likely result in your home insurance being voided. Overdriving can result in fires, it occurs seldom, but is a small risk according to my insurance company.

Bruce
Title: Re: Using lower watt bulbs than ballast can take - what happens?
Post by: nissannx on February 22, 2011, 07:05:58 PM
the ballast will still put out 40 watt regardles of what the bulbs are rated at. the 20 watt bulb will be getting 40 watt and will have a shorter life span. could it catch on fire? sure anything plugged in can. will it catch on fire? my guess is the bulb will burn out before that happens.