Has anybody ever seen a 1650 Watt metal halide ballast or lamp before?  I'm pretty sure they make them still but I never ever see them.

Yes, but not quite as common as the 1000w and 1500w sizes. Ballasts and lamps are still readily available. If im not mistaken, the 1650w ballast is only available in 208v, 240v, 277v and 480v. As far as I know a 120v capable version isn't available. I have only seen one installation of these, and it surprisingly wasn't a sports stadium, but an airplane hanger. They looked like typical 1000w high bays just with 1650w lamps and ballasts, I remember the lamps were Plusrite brand and didn't have white end paint on one end of the arctube, signifying a base-up lamp

Cool!  I wonder if one were to put a 1650 Watt lamp on a 1500 Watt ballast, would the lamp have a longer life?

Yes it would last longer, that small of a power decrease shouldn't affect the lamp life negatively, however the ballast wouldn't fare so well, the higher current draw from the lamp could be significant enough to overheat the 1500w ballast

Never heard of a 1650W MH lamp.Becuase of the wattage to run it from 120V you would need at least a 20A circuit and a transformer to step up the voltage to match the ballasts primary voltage.Seen 1500W ones at sports stadiums.GE made like a 2200-2400W MH fixture and bulb.They were double end bulbs.The fixtures ran from 208-480V only.Saw those lights in one of their lamp catalogs.

Yes it would last longer, that small of a power decrease shouldn't affect the lamp life negatively, however the ballast wouldn't fare so well, the higher current draw from the lamp could be significant enough to overheat the 1500w ballast

  Yeah, I didn't think of that.  I heard that running a 1500 watt lamp on a 1000 watt ballast seems to work pretty good though 

Yes, that's possible but only with the 1000w and 1500w lamps and ballasts, both lamps have essentially the same operating current and voltage, the 1500w lamp is simply an overdriven 1000w lamp, and if you compare the two you'll notice everything is identical on both lamps, the arc tube size, arc gap, etc... Ive seen a few installations of 1500w lamps on 1000w ballasts, and vise versa (1000w lamps on 1500w ballasts). The only difference ive noticed is the color temp of the 1500w system (regardless if a 1000w or 1500w lamp is installed) is quite warmer (3500K) and lamp life is about 8000 hours. The 1000w ballast operating a 1000w or 1500w lamp runs the usual cool white 4000K and youll get at least 12,000 hours out of the lamps.

Yes, that's possible but only with the 1000w and 1500w lamps and ballasts, both lamps have essentially the same operating current and voltage, the 1500w lamp is simply an overdriven 1000w lamp, and if you compare the two you'll notice everything is identical on both lamps, the arc tube size, arc gap, etc... Ive seen a few installations of 1500w lamps on 1000w ballasts, and vise versa (1000w lamps on 1500w ballasts). The only difference ive noticed is the color temp of the 1500w system (regardless if a 1000w or 1500w lamp is installed) is quite warmer (3500K) and lamp life is about 8000 hours. The 1000w ballast operating a 1000w or 1500w lamp runs the usual cool white 4000K and youll get at least 12,000 hours out of the lamps.

Sounds like lamp manufacturers were too cheap to make a proper 1500 watt size lol.

This lamp should operate with no problem with a dedicated choke here without an ignitor.