Don't run from the Indigo Lanterns! They just want to hug!
Hal Jordan has a bit of a chat with Black Hand to help the new reader learn some things. The Indigo Tribe bases its powers on compassion. What they feel is empathy for whoever they are interacting and thus they are capable of channeling all of the other emotions and have access to the other spectrum's powers. So when Black Hand is speaking with Hal, he feels willpower. Um. He feels willpowery. Willpowerful? How about we just go with stubborn. Maybe strong-minded? Confident! That'll work.
Hal thought that the Indigo Tribe couldn't access Willpower. That was probably a convenient plot device during the Blackest Night Story that never really made any sense and so is being done away with now. Or maybe it was just a trick so that Hal Jordan could shove his ring into Black Hand's face and recharge his ring on the Indigo energy.
So Hal doesn't need a battery, just an Indigo Lantern sidekick.
As Hal is zooming around the gigantic Indigo Tribe fortress, he comes across an enormous statue.
Everything is bigger in the Indigo Tribe!