understanding amperage draw with voltage conversion

[Practicalman]

if a 420 watt 12 vdc led light draws roughly 35 amps, what would the draw be on a generator putting out 120vac with a 120vac to12vdc converter

 

[Carolina]

Depends on the efficiency of the transformer, if I had to make an estimate I'd say 5 amps to account for the losses.

What is this light? something that high wattage would have to be used in a very, very big room, or outside.