Regarding warforged battery crystals
The crystals that are inside you must be charged to keep you alive and active. if your crystals run out of charge completely after 12 hours or 3 exhaustion levels you fall unconscious. Healing magic of any kind recharges the crystals for 1d4+1 hours. It requires 4 hours to recharge a set of crystals. Most warforged have 2 crystals, one and a backup. if both are removed you fall unconscious. So replacing them one at a time is common practice.