Replaced PS3 controller battery with old cell phone battery to avoid buying new controller. Should I be worried? It's not pretty, but it seems to work fine takes a charge again! :
1Pc 680mAh LIP1859 Battery for Sony Playstation 3 PS3 Controller with Tools and USB Cable|Batteries| - AliExpress
Repair: Replacing a dead PS3 Dualshock 3 controller battery – Darian Cabot
PS3 controller not charging solution guide
Paquete de dos baterías de repuesto + cable para controlador PS3 doble choque 3 seis ejes | eBay
Amazon.com: Pickle Power PS3 Controller Battery Replacement, 2 Pack LIP1359 Battery for Sony Playstation 3 PS3 Dualshock 3 CECHZC2E CECHZC2U Controller with USB Cable+Tools : Video Games
Wireless Battery Indicator (PS3) - RetroPie Forum
impulsegamer.com - Replacing the battery in a PS3 DualShock Controller - impulsegamer.com