I tried using an extended battery "L40G4" that makes GoPro's battery last longer than three times - GIGAZINE
Extended Battery Pack 4000mAh (Limefuel Epic L40GH) for GoPro HERO, External Mini USB Includes Extended Backdoor Housing up to 40 Meters, for entry-level camera only NOT COMPATIBLE with Hero 4, Hero 3/3+Patent
Amazon.com : Wasabi Power Extended Battery for GoPro HERO : Electronics