Fun With Batteries and Remotely controlling Doors

(I know this isn't directly PC related but i dunno where else to put it)

Hey guys

I've been looking at a method of wiring up a regular car radio control system to an I/O port on my pc (Midi probably) and using software to control the radio commands to power motors i'll scatter around the room.

It's something i've been thinking about doing and all tho i'm familiar with on/off switching and basic programming for such function i suck at chemistry or mechanics or whatever it is that this battery thing is about.

In short , as an example can i power two 4.8 v motors with one 9.6 battery pack (i'll mainly be using rc toy battery packs) in case one motor's torque/output isn't enough to say, flip a switch. How should the wiring for such a scenario work?

Also, how do i know how far i can push a motor? (ie: how many volts i can push through it without frying it.) They're mostly small toy rc car motors i ripped out of my family's toy graveyard.

Any help/related web pages welcome

Thanks in advance

Jam it back in, in the dark.