Found it. Get these.
here is the thread from the past on this
forums.radioreference.com
here is the thread from the past on this

BCD436HP/BCD536HP: - External Battery pack
Anyone ever use an external battery pack for longer scanning? Something like the link below. https://www.amazon.com/Aibocn-External-Battery-Flashlight-Smartphones/dp/B00VWV8LD4