What I got from the seasonal box

You used to only be able to get it by paying for batteries, but it's great that free-to-play players can get it now.

Congrats But the fact is that the energy you get from opening boxes is fixed at 500 per season. (You can get 10 or 100 energy probabilistically, but the total is always a maximum of 500 energy) The energy from opening boxes is a maximum of 500 per season + a maximum of 450 from the cumulative reward for opening 300 boxes.

Congrats!