Dear Riot, Athene's Unholy Grail New Passive

Passive: Gain a portion of damage dealt to ALLIED champions as blood charges. Healing or shielding another ally consumes blood charges to heal them for the amount stored.

It was my understanding when Xypherous posted the preview of the new items on the pbe boards that you gained blood charges through a portion of damage dealt to ENEMY champions. Is this a typo or do our allies have to take plenty of damage before we can use the heal on them?