HID light question

[JerryMawuana]

Can I put a 600 watt metal halide bulb in a 400 watt ballast, or a 400 watt HPS in a 600 watt ballast? I bought a 600 watt HID light kit, then realized I need to have it turned down to 400 watts for my grow space. So I bought the 400 watt light kit for my veg tent and have the 600 (turned down to 400) in my budding tent. Now I have the wrong wattage for extra bulbs.

 

[DrPhoton]

Some ballasts are multi wattage compatible. But most ballasts are not and require that they be used with the corrosponding wattage that they are designed for. This is because the starter curcuit is designed for a specific type of resistance, which is different for each type of bulb wattage. Although in theory it can work, using a lower wattage with a ballast turned down, the starter circuit could degrade the life of the bulb or worse, break it. Which is why manufacturers never recommend any other bulb wattage other than what it has been designed for.

 

[JerryMawuana]

Damn, I guess I'll just have to add them to the collection of unused equipment. Thank you for the answer.