12000k xenon car lights

[sphelps]

Originally Posted by dabandit

how is it more efficient to run a 70w over a 35w?

Not sure I follow, is that something I said or someone else?

Efficiency can be interpolated many different ways but in the hobby I believe we tend to use PAR compared to actual measured power used. So a 10K would be more efficient than a 20K of the same wattage. So a 70W MH could be more efficient than a 35W Xenon or different lighting source, but it all depends on the PAR rating for Xenon and of course bulbs and ballasts used.