Dual USB Power Bank Case 16*18650 Battery Charger Box DIY Shell Kit LED Display I5G5 - Walmart.com
USB / DC / Solar Lithium Ion/Polymer charger [Rev C] : ID 390 : $17.50 : Adafruit Industries, Unique & fun DIY electronics and kits
2S LiPo/Lion Battery Charger Using Micro USB 5V/2A Power Supply : 3 Steps - Instructables
5V 2A Type-C USB 3.7V 18650 Lithium Li-ion Battery Charger Module DIY Power Bank | eBay
Amazon.com: DROK® Mini USB DC-DC Step Up Converter 3V to 5V 2A Mobile Power Supply Charger Board with Battery Indicator for Tablet PC iPad iPhone Charging DIY : Electronics
How to Make a DIY Battery-Powered USB Charger « Null Byte :: WonderHowTo