An easy way to look at batteries is to consider the mAh size of the battery like a fuel tank. The larger the mAh the larger the fuel tank so the longer you can fly.

Now if you increase the voltage you'll increase the kV or RPM's per volt (in the case of Lipo's is 7.4v for a 2S, 11.1v for a 3S, 14.8v for a 4S, etc - 3.7v per cell). With a voltage change you are dealing with the power output, measured in watts, and the amount or current, or Amps drawn, etc. Change your voltage and you change the watts of power output, thus the amount of current, or amps the motor sees has changed. The guys in the electric form are the ones who are the experts on this stuff. Your motor manufacturer should have provided documentation with your motor, or have available the information as to what amperage the motor will pull using specific props at a specific voltage.

An increase from 2100 mAh to 2200 mAh, or even to 2500 mAh, won't have any effect except to lengthen the flight time just a tad and add a hair more weight due to the increase battery capacity. But with 2100 to 2200 you probably wont notice the difference.

Hogflyer