There are comments regarding the 250 watt and 400 watt radiums only lasting about 6 months. The 250 watt Radiums, eventhough they are Mogul based, are spec'd for the M80 magnetic HQI ballast. So they actually are NOT being overdriven when run on that ballast. The 400 watt american version of an HQI ballast is actually, I believe, a 430 watt HPS ballast. It's not actually equivalent to the european 400 watt HQI ballast but I guess it is the magnetic ballast closest to meeting spec in the US. But this is all from memory, I havent used 400 watt lamps and dont know all the details and could be mistaken on some of this.
The 150 watt de is spec'd for the M81 HQI or can be run on a pulse start or electronic. So again, it is NOT overdriven being run on the 150 HQI M81 or magnetic pulse start (the 150 watt pulse start actually has the same drive specs as the M81 HQI [the 250 watt pulse start and HQI are different in both regards] but different starting specs). Since the 150 watt Radiums are not as talked about as the 250 and 400 watt, Im not sure what the concensus is on how long they last. But again, they are NOT overdriven on the HQI ballast, they are underdriven to some degree on the electronics. You can see this when comparing par numbers on Sanjays site with the radium on M81 versus the electronics.
So I dont believe that the 250 watt radium has a shorter life on the spec M80 ballast, I think they just have a shorter life, period, despite them being a quality made lamp. The 400 watt versions I dont know about, I dont know what the 430 watt ballast does to them compared to an electronic.
The 150 watt versions I have not heard enough reports about so I think you will just have to wait and see.
But if you can get a hold of Paulerik ... he is a halide expert (does it for a living) and can tell you anything about any of the ballasts and most of the bulbs. He would probably have specifics about the 150 watt radiums and how they hold up. He's a nice guy too so if you do a member search and shoot him a pm he would be happy to help, Im sure.
