I have tested the Anker Astro 3e 10,000 mah on my hub dynamo. It appeared to be working with the lights blinking. But after 8 hours of biking it still did not have any charge within it. My USB adapter is 5v 1a. I have also tested the Mophie Juicepack 4,000mah, which didn't work.

Unsure how much charge I can produce within 8 hours though, 3,000 mah possibly? Maybe the Anker just needed another couple hours to get over the edge.