Any reliable power bank recommendations for Boomtown?

I’m a first-timer heading to Boomtown this August and I'm starting to get my packing list sorted! I’ve been reading a lot about how hilly the site is, so I’m trying to be strategic with my gear. Does anyone have recommendations for a durable power bank that has actually held up well over the weekend? I’m looking for something reliable that keeps my phone charged for photos and meeting up with friends without being too heavy to carry around all day. Any tried and tested advice for a newcomer would be amazing.