Zzzap can hold his form for 3 days

“I’m wiped. I’ve got to be honest … I don’t know how much more use I’m going to be to you.”
St. George looked over at the tower guards. They’d rushed down to a waiting Humvee. One of them manned the machine gun on the roof. “Can you recharge Cerberus one more time,” he asked, “maybe hold it together for a little while longer?”
“How long is that?”
“If we don’t ask you to do anything else but be a presence … a day or two?”
“Ouch,” said the wraith. “You serious?”
“I need you here, Barry. They need to see us. At night they need to see you.”
“Yeah, yeah, I know,” sighed Zzzap. “We’re heroes and all that.”

Excerpt From Ex-Patriots, pg 596
Peter Clines
https://books.apple.com/us/book/ex-patriots/id585738393