1. You will get a free Mecha Charge every 8 hours, and you can save up to 3. Charging an Ultra Mecha with a free Mecha Charge can get a temporary EXP Bonus for this type of Ultra Mecha. The higher the bonus, the higher the EXP Gain each time you charge it. However, once the Super Mecha evolves, its temporary EXP Bonus will be cleared.
2. You can upgrade Ultra Mechas quickly by using Mecha Charge. Mecha Charge can be obtained from attacking Rebels, completing events, assembling Mechas, and purchasing packs.
3. The higher the Mecha Factory level, the higher the EXP Bonus of Charging Mechas. You can view the Mecha Factory status for more details.