Found this extended radio battery that takes AA batteries and since I’m not licensed to use my radio and seems like a good idea to use it as a dummy battery would also avoid any concern from security at cons 
HYS 6x AA Battery Case Compatible with Baofeng UV-5R UV-5R Plus UV-5RB UV-5RE UV-5RA Walkie Talkie https://amzn.eu/d/0hUjqCPE