[Christ]

Here's a thought - It takes energy to compress air... and it takes MORE ENERGY still to keep it compressed, while still flowing air. Without doing the math, I can make the assumption that energy required for a direct compression device to achieve and maintain compression will increase in a strictly non-linear relationship with the amount of compression achieved.

(In other words, the higher the boost, the more the amp draw. The charger won't run at full capacity all the time, but when it gets into boost, it's probably going to take more than it's really rated for, if it can maintain boost at all.)