Energy on players is a scarce resource in Futuball. The normal way it goes is that when a player is out of energy his career is done and you have to dismantle him and build a new.

The rechargers are not made so you can recharge your entire team and keep them forever. It is made so you can recharge you absolute favourite players - and play them once in a while - instead of having to dismantle them when their energy hits 0.

That is also why it is KEY to save energy of your best players when they are not needed.

The perfect win in Futuball is a 1 goal win. If you win by 10 goals you have used energy of too good player compared to what you kind of quality players could have used to still get the win.