DIY metal halide question

[Delphinus]

Originally Posted by StirCrazy

almost all 250 watt 10000K bulbs in the hobby should be run on a 250 watt HQI ballast. the readium especialy, as almost every bulb is built to german specs which are based on the HQI ballast.

Just a appendix to what Steve says ... there is only one HQI ballast that I know of in the cap/coil style (i.e., non-electronic) ballast and it is made by Advance. (Advance catalog #71A5880 [ link to info ]).

The one thing to keep in mind when using this ballast, notice that the "BTL" number associated with the ignitor is 5 feet. "BTL" is "ballast to lamp" distance, this is the maximum length of wiring between ballast and lamp, including ballast to ignitor. 5 feet can get used up pretty quickly (i.e., may not even be adequate if you want your ballasts on the floor or in a back room), so you may need a creative solution. BTL is typically a function of the ignitor, with other ballasts you can get "long distance" ignitors to get around this problem but as far as I know there is no long-distance ignitor for the HQI ballasts (M80 and M81).

But 5 feet is probably not all that bad to work with, just so long as you know that there is this limitation...

cheers