I bought the extended Gamepad battery. I see Nintendo planned a spot for it all along. : r/wiiu
Nintendo Wii U GamePad Battery: Replacement Part #ARR-002
Can't believe this is the battery they ship with the Wii U Gamepad. (Separate extended battery underneath) : r/gaming
Amazon.com: UCEC Wii U Gamepad Battery, Wii U Accessories 3600 mAh Wii U Battery Replacement Rechargeable Battery Pack Compatible for Nintendo Wii U Gamepad : Video Games
Guide to the Best Wii U Replacement GamePad Battery - Nerd Techy
Game Console Battery 3.7v/1500mah Wup-012 For Nintendo Wiiu/gamepad,wup-010,wii U,wup010 - Digital Batteries - AliExpress
Nintendo Wii U GamePad WUP-003 Replacement Battery: BatteryClerk.com
Wii U GamePad high-capacity battery now available, promises 8 hours of use - GameSpot
OEM Rechargeable Extended Battery Pack For Nintendo Wii U Gamepad 3600mAh 3.7V | eBay
Comparing all three batteries for the Wii U Gamepad - YouTube
Amazon.com: Hisewen Wii U Gamepad Battery, 2200mAh Replacement Rechargeable Battery Pack for Nintendo Wii U Gamepad WUP-012, WUP-010 : Video Games
Larger Wii U GamePad Battery, Wii Remote Charging Set coming to Australia - Vooks
Amazon.com: 3.7V 1500mAh Battery Pack for Nintendo Wii U Gamepad WUP-012, WUP-010 : Video Games