[ContainerTed]

Of course, you can put light bulbs in series and the voltage becomes less problematic. At 240 AC, 20 headlights would satisfy the voltage. The cycles, 60 here and 50 there is not a factor to the headlights either. Magnesium filaments in the lights don't care about AC vs DC. They only want enough current to fully excite the filament, thus producing the light. And that brings us back to the current (the amps). The electrical formula is "Voltage is equal to the Current times the Resistance". Thus, the resistance of the filament has a direct effect on the current for any given voltage. The higher the resistance, the lower the current.

My conclusion would be, "Without knowing the resistance of the filaments of the light bulbs, it would be impossible to calculate the Amps precisely, thus creating a safety issue like Worth was describing.

This safety thing is why I use "Florescent" bulbs for all my plants - Probably the easiest to do safely. Everything else produces a lot of heat that might not be wanted. I've built a lot of power supplies for this or that. I currently have a 12 volt supply that has a working capability of a bit more than 20 amps continuously. But even a few of those would not run a bunch of headlights.

I recommend you reconsider CFL's as being the only safe thing to do.