Wii Balance Board Battery Case Replacement - iFixit Repair Guide
Nintendo Support: How to Install or Change the Batteries in a Wii Balance Board
Wii Rechargeable Battery Pak Designed for Wii Fit : Video Games - Amazon.com
Wii Balance Board Alarm Clock – Closing the lid - Niall Bunting
CTA Digital Battery Pack for Wii Balance Board - Newegg.com
Wii Fit Balance Board - Leaking batteries - YouTube
Corrosion from batteries that leaked on Wii Balance Board (more explanation in comment) : r/consolerepair
Accidentally left the batteries in my wii balance board for 9 years and it corroded the converters away, is it possible for me to fix? : r/consolerepair