Help: want to do something but not sure if it will work (electronic guys)

[Firstcig]

Hey, I want to build mod my idea is a 3.7 mod with passthru, I've found a box with usb connection at the back here:
$7.08 2*18650 Battery Holder Case with Dual USB Ports (5V/1.5A Output) - charges iPhone/Android / emergency power pack / 1S2P at FastTech - Worldwide Free Shipping
so my idea is to pull out the batterie spring on the left side and then drill a hole put a 510 connection and next to it a button and solder a wire to the gold part near the circuit board so my question is: will it work? try to talk simple I don't really know electronics

ilustration:
http://oi43.tinypic.com/2ujrwiq.jpg

 

[Dougiestyle]

So, you want to delete one cell and hook your switch/connector to the parallel cell and use the on-board charger to keep the battery charged via miniUSB. It will work. It will not be a true passthrough, as the voltage at the connector will be relative to what voltage the cell provides. The chrager circuit is most likely not capable of producing the current to run an atty. Be aware that Li-Ion batteries do not like parasitic drain while charging. While the mod will work, the battery longevity will decrease if you vape while charging.

 

[moijamie]

So, you want to delete one cell and hook your switch/connector to the parallel cell and use the on-board charger to keep the battery charged via miniUSB. It will work. It will not be a true passthrough, as the voltage at the connector will be relative to what voltage the cell provides. The chrager circuit is most likely not capable of producing the current to run an atty. Be aware that Li-Ion batteries do not like parasitic drain while charging. While the mod will work, the battery longevity will decrease if you vape while charging.

what you just wrote is as confusing as the description of a juice

 

[Firstcig]

but if I'll take out the batterie and plug to the usb will it still work? (trying to prevent decrease in the batterie longevity haha)

btw my english kind of sucks so I probably didn't understand some a long the whole comment