tech and challenge question about remotes

one of our school teams has a remote that now won’t hold a charge. We’ve changed the battery and the radio. What do the rules say about plugging a juice box in to the remote so that the students can use it in competition? We’ve contacted Vex and they say there is a 4 week waiting period for a new remote. Our first competition is in 2 weeks. What can we do?

I’d say this is fine. addresses robot batteries but there is no talk of controller power source anywhere. In fact, in VRC, we once had mains power adaptors at the driver posts that could be used to power the controllers if required.
I’d say a power bank will be fine although probably best to post in the official Q&A I guess.