Easy to Build 12V 18650 3S Li Ion Power Bank

This is a case that was designed around this part from Aliexpress
12V 3S Power Wall 18650 Battery Pack 3S BMS 

The “Cover” and “Slim Edition base” must be printed with Flexible Filament

Part List Aliexpress:

• 12V 3S Power Wall 18650 Battery Pack 3S BMS Li-ion Lithium 18650 Battery Holder BMS PCB DIY Ebike Solar Battery 3S Battery Box
• 12/16/19/22mm Waterproof Metal Push Button Switch LED Light Momentary Latching Car Engine Power Switch 5V 12V 24V 220V Red Blue
• 0 28 Inch DC LED Digital Voltmeter 0 100V Voltage Meter Auto Car Mobile Power Voltage Tester Detector 12V Red Green Blue Yellow
• QC3.0 QC2.0 USB DC-DC Buck Converter Charging Step Down Module 6-32V 9V 12V 24V to Fast Quick Charger 3V 5V 12V Circuit Board 

Optional: 

• DC 5V to DC 6V 12V Power Supply Boost Line Step UP Module USB Connector Converter Adapter USB Cable Battery Charger