Drawbacks of this internal charger for charge-n-play?

[Fluxedo]

http://www.batteryspace.com/Smart-DC-Ch ... -Pack.aspx

other than having .2 less amps output than the standard charger from BatterySpace, what would could go bad about salvaging the (seemingly) small chip from this and putting it in a portable so you can just feed it 12v for all both plat and charge and switch between charge and battery as needed?

 

[laingsoft]

Not sure, I would say that it is probably something stupid simple like a linear voltage regulator and a zener diode.

You'd probably be better off just building your own charging circuit.