Hogwarts Mystery Free Energy (5+ ways)

1. Energy Locations (~ 9 energy bolts, ~ 2-3 times a day)
Some (like House Elf) take longer to reappear than others.
 * 1) East Towers
 * 2) * Dark picture frame - girl appears when tapped
 * 3) * Peeves, near Divination Classroom - zooms around and disappears when tapped
 * 4) West Towers
 * 5) * Picture frame to the left of Prefects' bathroom - oranges appear when tapped​
 * 6) Lower Floor - West
 * 7) * Unlit right column near Great Hall​ - becomes lit when tapped
 * 8) * Middle soldier to the right of Great Hall - switches sword for shield when tapped
 * 9) Dungeons
 * 10) * House elf between Kitchen and Potions Classroom - scurries away when tapped
 * 11) Castle grounds
 * 12) * Twig between Whomping Willow and Hagrid's Hut - Fang comes and takes it away when tapped
 * 13) Lower Floor - East (unlocks 2nd year)
 * 14) * Scattered books between Library and History of Magic Classroom - becomes a neat pile when tapped
 * 15) Hogsmeade (unlocks 3rd year)
 * 16) * Sledding student between Honeydukes and The Three Broomsticks - slides down when tapped

2. Leveling up (all energy restored)
Tap on your character's face (upper left) and see your level and level progress bar underneath your name (top left again). When the bar becomes full and you level up, you regain all energy lost (i.e. back to 28/28). This can be useful when trying to complete lessons/quests. Anything that gives you XP (lessons, side quests, etc.) will add to your level progress bar.

3. Friends (starts with +5 energy)
Tap the person icon on the bottom right of your screen to see your friendship levels. After a certain level, the reward for leveling up friendship is energy. The higher the next friendship level, the higher the energy reward (+5, +10, +15, etc.).

You can raise friendship levels by playing gobstones with them in the Courtyard or having a meal with them in the Great Hall (both places are located in Lower Floor - West). Playing gobstones becomes available every 16 hours and provides you +25 to the friendship level if you obtain all 3 diamonds. Meal with a friend becomes available every 6 hours and provides you +9 to the friendship level if you obtain all 3 diamonds. Both actions cost coins, obtained very easily for free by completing quests/lessons/etc.

4. Pets (up to +4 energy, ~3-4 times a day)
You can purchase pets with diamonds and keep them in your dormitory. Diamonds can be obtained for free over time by completing quests/lessons/etc.You can keep a pet with you at all times, which can be helpful for seeing when your pets fall asleep. When pets fall asleep, tapping them will provide you one bolt of energy each.

5. Watching a video (+3 energy, a few times a day)
Sometimes when you run out of energy in the middle of a task, you get the option of watching a 30 second advertisement to get 3 bolts of energy. You must keep pressing until you see the "Out of Energy" message in order to see this option. You can sometimes collect the 3 bolts back to back (i.e. 6 bolts at a time).

6. Earning stars (~1-2 energy, randomly)
Sometimes a reward option for earning a star in a lesson/quest is +1 energy. This is not a great deal, but is an option when desperate. Sometimes 1-2 bolts of energy are added to your energy bar automatically when XP is added to your level meter after earning a star.

7. Duelling club (+4 energy for every win)
Duelling club is located in Dungeons. When it is open, you get 3 tickets for the entire time period. For every duel you win, you sometimes earn +4 energy (sometimes the reward is coins instead). You use up a ticket every time you lose. After 3 losses, you cannot duel in duelling club again until it reopens.

8. Diamonds (+10-60 energy)
You can obtain diamonds for free over time by completing quests/lessons/etc. If you're in a pinch, you can use these diamonds to get energy by pressing the + sign next to the energy bar.

9. Waiting (+1 energy every 4 minutes)
Not the best option, but you do get 15 bolts of energy every hour for free until fully recharged.

Notes about obtaining energy

 * 1) You cannot go over your energy limit except in a few instances (buying energy with diamonds, leveling up friendships, duelling club). Thus, tapping Peeves with a full energy bar does not help you get more energy.
 * 2) You can increase your energy limit (usually by +1) by completing certain flying classes. You can see options open to you by tapping the book icon on the bottom right and selecting "Flying".