MH ballast/bulb question

[cschweitzer]

Can you underrate a ballast in comparison to the bulb (175W ballast and 250W bulb) or vice versa(250W ballast and 175W bulb)? Thanks.

 

[eckrynock]

Nope.

 

[cozart]

so are you saying you can run a 175w bulb on a 250w ballast?

 

[markandkristen]

well grab a old bulb set the timer...and see if the house burns ... just kidding. .. im curious as well

 

[Stoney Mahony]

Yes you can burn a lower wattage bulb on a higher wattage ballast just not vise versa. The bulb needs an initial burst of energy(start up watts) to ignite and then it slowly lights. The bulb will burn brighter but it will shorten the length of the bulb and slightly altrer the spectrum twords the white/yellow end of the spectrum. I have run 400w on 1000w ballast w/ no prob but the bulbs only last a few months. They put out app. 30,000 more lumens though. In hydroponics it is a generally accepted idea to burn 400 watters on 1000w ballast and replace them every 6 months instead of every year b/c 400's are so much cheaper than 1000's and it does'nt matter as much if you have a spectral shift. Don't try 250's on a 1000 balast.... they blow in few weeks, and I mean BLOW !. Ive tested alot of stupid stuff, but glad I can actually give some advise on it.

 

[Mr James]

<a href=showthread.php?s=&postid=7622283#post7622283 target=_blank>Originally posted</a> by Stoney Mahony
Yes you can burn a lower wattage bulb on a higher wattage ballast just not vise versa.

I guess I disagree.. and with proof. I am running a 175w mh ballast (CSL - M57 I believe) with a 250w mh bulb ()Reeflux 14k). I never thought it would fire either, but it does. I certainly didn't plan it that way, but the guy who sold me his entire system sold it to me a 3 x 250w. I looked at the bulbs which said 250w on the side, but never looked at the ballast until recently. I am currently running it over my 180g in the middle and it is flanked by two regular 250w mh retro's.

One more edit: He ran it this way for four months until he tore it down and sold it to me. So far nothing has "blown up". I have been running it for a over a month now.

Edit: Found a picture of it - not bad looking, but certainly not efficient.

 

[Stoney Mahony]

I don't have any 175 ballasts to do tests on, only 400's and 1000's. 1000 watt bulb will not light on a 400 ballast(at least not on the 5 different kinds I have tried). Maybe your 250w reeflux has a low start up wattage. If you check the manufacturer website, they usually give these statistics. I would not think Running a higher watt bulb(if it will light) on a low ballast would not harm the bulb b/c your not even using it to it's max. It might even last longer.