I've tested this across several games and on 3 different champs. Initially, healing gains the champs 2 charges (Aspect of Life, KF Doomie, Nectar Fairy). After more than 1 champ started healing others, charges started getting odd. Sometimes a champ would heal and not gain charges after, while the other two did, and other times, all 3 gained charges, this happened across charged heal, heal champ and healing breath. It's also worth noting that on Nectar Fairy and Aspect of life, charged heal uses two charges and heal charged 2 grants 2 charges, so once they have the initial 2 needed, they'll never run out of charges to heal with. This is countered on the doomie by psychic amped though.
