Assuming a 55watt H7 produces 1335 lumens at 12.8v, and looking at other overwattage bulb ratings vs normal ratings, an 80 watt H7 should produce 1942 lumens at 12.8 volts. I made a little chart of 80 watt H7 output at various voltages.



1363 lumens at 11.5v

1484 lumens at 11.8v

1942 lumens at 12.8v

2203 lumens at 13.3v

2610 lumens at 14.0v

Certainly explains the difference in the picture above.

I used this equation to calculate the lumens available at different voltages.