Energy is consumed to enter any match other than Survivor. Any card has 10 bars of energy maximum, represented by lilac bars at the bottom of the card. Standard and challenge battles may deplete 1 to 3 bars for each fight, and Online Battles use 2. Breakthrough Mode requires that you spend 10 Energy for the whole team in order to enter the battle, paying for all three matches.Energy recharges at a rate of 1 bar every 8 minutes, and the rate can be increased by 10% through certain Support Cards. They could also be instantly refilled by energy cards, awarded randomly in battles or bought with real life money. Starting from the 2.9 update, you can replenish your characters' energy for up to 3 bars to all three characters in the team by watching a 30-second advertisement (requires internet connection), or earn free energy cards through completing certain matches.
Rotating your roster would be useful to avoid running out of energy.
Energy is very often confused with Power, which is gained and used during a fight to use Special Attacks and Super Moves. This is further exacerbated by official text using the wrong term. For example, for a long time Superman/Man of Steel's passive description used to refer to energy, despite that it actually means power, prior to being corrected. Raven/Rebirth, released later, has this problem again.
- It used to be possible to sort character cards by energy before this functionality was removed.
- Previously Challenge Credits are required on top of energy to enter challenge battles. Challenge Credits are, in turn, earned by completing normal battles, at a rate of 1 credit per 2 energy bars spent.