Mobile battery charger

The idea was to give a second life to an unused li-po rc car battery. Since it has a capacity of 16.000mAh I thought that will be a good idea to recycle it as a power bank, so I got a dual PCB battery charger on ebay https://goo.gl/jVrJUL and designed a box to put all together.

Features:

Motherboard comes with protection function: Charging overcharge protection, over-discharge protection, overcurrent protection.
Intelligent output device after charging full, automatically stop charging, to prevent mobile phones overcharge.
Output voltage and current stable, will not harm user devices.

Specifications:

Micro USB input: 5V 1A
USB Output: 5V 2.1A / 5V 1A(Dual USB interface)
Charging display: intelligent digital display
Batteries Type: liquid lithium-ion batteries (18650)
Product Size: 57mm x 28mm
Screen size:27mm x 17mm

Installation instructions:

The circuit board is connected to the battery negative B-, B + is the positive, do not connecting reversed, connect