There's another thread running now you might want to look at.

www.rcuniverse.com/forum/m_11580992/tm.htm

Not much to do with a second battery pack other than hook it up. I'm referring to A123's as ther is no voltage reduction needed and the full current of the battery is available without a regulator.

I like using two 2300 A123's rather than on 4600. If one battery goes south the other is ready and willing to provide power. I also like to put a schottky diode in series (not really necessary) with the battery and the switch in the unlikely event that a cell would short out rather than become an open circuit. That isolates it from the system.

Use a heavy duty "Y" connector or hub to hook it into the receiver, the S.Bus2 port or an open servo channel. Note: All the red servo wires and black servo wires are all hooked up in parallel so it doesn really matter where you connect it. Preferably "Y" it to the servos that would draw the most current (flaps or big rudders).

Happy Flying!

Steve<br type="_moz" />