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MH ballast question

Discussion in 'Lighting and Equipment' started by MuralReef, Dec 3, 2018.

  1. MuralReef

    MuralReef Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. MASC Vice-President

    I need to replace a ballast and I have a spare, but it is not the same size. The current ballast is a 250 w HQI selectable and this is a 400 w selectable. It does not have the wattages marked on the dial. 1. Can I use it and try to match the dials position with my other selectable 400 watt ballast? 2. Does anyone how to gauge or measure the output of the ballast? If so what wattage is a 250 watt HQI overdrive to?
     
  2. TheRealChrisBrown

    TheRealChrisBrown Barracuda Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. B.O.D. Member-at-Large

    That sounds like a @jda123 question. I'm pretty sure he told me the wattage on an overdriven 250w...but I couldn't find it in my conversations about halides with him. I'll keep looking.
     
  3. scchase

    scchase Marlin Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. B.O.D. Member-at-Large

    Most the 400 wt selectable the 250HQI will be the second click clockwise 400 3rd click 4th click is 400 overdriven. 250 wt HQI is overdriven to 280 wts
     
  4. MuralReef

    MuralReef Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. MASC Vice-President

    I wish it were that simple. The dial turns but there are no set positions or clicks. That is what I see on my other 400 watt ballasts but not this one. This one is wired the same as my 250 watt pendants and is different than the two 400’s. Just rather not rewire it.


    Sent from my iPhone using MASC mobile app
     
  5. TheRealChrisBrown

    TheRealChrisBrown Barracuda Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. B.O.D. Member-at-Large

    Would one of those Kill-a-Watt things work to tell you how much juice the ballast is pulling...and then fine tune it to 280w if that is what you are looking for?
     
  6. SynDen

    SynDen Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. M.A.S.C President M.A.S.C Webmaster

    you could use the par meter and just ramp it up to match the other ones par
     
  7. MuralReef

    MuralReef Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. MASC Vice-President

    That’s what I was wondering but I really don’t know how ballasts work and if they draw as much as they pass on to the bulb.


    Sent from my iPhone using MASC mobile app
     
  8. MuralReef

    MuralReef Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. MASC Vice-President

    Another good idea!


    Sent from my iPhone using MASC mobile app
     
  9. zombie

    zombie Tuna M.A.S.C Club Member

    They are not super efficient. The power drawn from the wall will be between 110% to 130% what is actually delivered to the bulb. You could plug one into a kill a watt to get a baseline wattage and then plug the others in and turn the dial until they basically match though.

    Sent from my SM-G965U using MASC mobile app
     
  10. jda123

    jda123 Tuna M.A.S.C Club Member

    Real m80 is about 330-335w at the wall. You can use a kill-a-watt and see which is which.

    The good thing is that a real HQI bulb will be made to take every bit of that wattage, so even if you don't quite get there, it should be OK.

    Color can be a bit different if you use less wattage, but you can use the color to match as well.

    Most magnetic ballasts have about a 5-10% overhead, which is very similar, or maybe even a bit less, than a LED transformer. An electronic ballast is more like 1% of overhead, so maybe look for 290-300w at the wall from an electronic ballast.
     
  11. MuralReef

    MuralReef Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. MASC Vice-President

    According to the Kill-A-Watt the consistent working 250 watt HQI ballast is drawing 280 watts. On the lowest setting the 400 is drawing 380 watts, but the color and brightness visually appear the same.
     
  12. MuralReef

    MuralReef Shark Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. MASC Vice-President

    I will continue to monitor throughout the day. It is now reading around 310.
     

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