Source Gamepad Controller Extended Life Rechargeable Battery Pack For Nintendo Wii U on m.alibaba.com
Amazon.com: 3.7V 1500mAh Battery Pack for Nintendo Wii U Gamepad WUP-012, WUP-010 : Video Games
Nintendo Wii U Wii U GamePad WUP-010 1500mAh Game Replacement Battery: BatteryClerk.ca
in stock)6600mAh Wii U Gamepad Battery Replacement Rechargeable for Nintendo Wii U Controller** | Lazada PH
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 WUP-010, WUP-012 : Video Games
Wii U GamePad Battery Pack Hands-on Preview - Hands-on Preview - Nintendo World Report
Amazon.com: iFixit Battery Compatible with Nintendo Wii U Gamepad : Video Games
Wii U GamePad battery life gets a boost from new Nyko accessories - Polygon
Can't believe this is the battery they ship with the Wii U Gamepad. (Separate extended battery underneath) : r/gaming