Newer batteries will include a JST cable with male connector already soldered to the battery. The length of the cable included is enough to reach the power charing circuit in this project.
Fasten two #4-40 3/8 to the bottom part of the enclosure near the bottom with the cut out in the center. This is where the microUSB port of the PowerBoost 500C will be.
Place the PowerBoost500C on to the lower center area of back.stl part with the micro USB port facing the cutout.
Line up the mounting holes to the stand-offs and hold the PCB to the enclosure with one hand. With the other hand, fasten two #4-40 3/8 flat Phillips machine screws to the mounting holes untl it's fully flush with the surface of the enclosure.
With wires solder to slide switch, install the switch into the bottom enclosure part by fitting it through the cut out with wires in first.
Solder wires from slide switch to BAT, EN and GND pins on the PowerBoost 500C.
Plug in the JST connector from the 6600mAh lithium polymer battery to the JST port on the PowerBoost 500C.
Turn the slide switch on to test the PowerBoost 500C. The blue LED should light up indicating a charged battery - Red LED means the battery needs to be charged.
If no LED's turn on, double check your wiring.
With the PowerBoost 500C tested and working, turn it off and unplug the JST and set the battery aside.