Do you have a technical question that doesn't really fit a specific console? Want some general info on electronics, hacking, making cookies, etc? Here's the place to ask! Go nuts.
In series, volts are addative, amps care constant, in parrallel, amps are addative, and voltage is constant. What you have here is 2 series circuits in parrallel, which means yes your get 4.5 volts, and you get 4000 mAh, or 4 Ah.