Amazon.com: Qimoo 3.7V 4400mah-16.28Wh Rechargeable Battery Pack Lithium Ion Batteries with PH2.0mm Connector for DIY Electronics Products, Toys, Lighting, Bluetooth Equipment : Health & Household
DIY Li-ion battery building kit | Make your own 18650 packs by Micah Toll — Kickstarter
Make Your Own Li-Ion Battery Pack : 5 Steps (with Pictures) - Instructables