Time Cheat
Set the time ahead on your device to restore your energy immediately. It takes 5 minutes to restore one energy, so if you need all 15 back you will have to set the time ahead by 75 minutes. If you use this cheat though it is safer to set your device ahead by only 20 minutes otherwise you run the risk of the game's servers recalculating and knocking you back into pre-cheat time. This cheat can also be used on any research you want finished immediately.
If you need more help, we've got more HonorBound cheats and also check out all of the answers for this game
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