How exactly does Daruk's Protection work, deplete its charges, and recharge?

Solution 1:

1. According to Zeldapedia, Daruk's Protection blocks damage from everything, except for some environmental/undefendable damage, such as:

• falling into molten lava
• falling into an abyss,
• a pummeling from Magda
• damage caused by drowning.

2. You can hold LT indefinitely, and doing so doesn't use up a charge until you are attacked or something else happens that would normally cause you damage.

3. A charge is used up each time you are attacked, or when the skill protects you from another damage causing event. (Note that there seems to be a short period of ongoing invincibility after the initial attack, so one charge may protect you from a few hits if they come in close succession.) It stops working after absorbing three attacks, a.k.a. using three charges. After this, it takes 18 minutes for the three charges to become available again.