Battery and trim setting ?

I have 2 batteries for my HB: stock e-sky 11.1-800 and an xtreme 11.1-850mhz. my question is why does it feel the heli flies different on each battery. I always seem to have to re-trim or adjust the prop trim dial when i flying the other battery. is this normal? I always thought the MHz would just affect fly time and nothing else. was I wrong? do most people by 2 of the same battery?

thanks!

a little correction, is not mhz, its mah.
Mine also like that. I have several battery, the same 25C, but it affect the heli flies. I have no idea why?

Because one battery is a little bit more powerful and gives more current to the motor. Then motors spins faster and your trimming doesn't work.

If this is true (larger battery gives more current to the motor), wouldn't it give more current to both motors? Is the current not limited by the speed controller in the 4 in 1? I can understand different batteries with different weights affecting the CG but it seems more power would be more power to both motors canceling out any differeng affect.

and when people have multiple batteries, do they typically stick with identical batteries to avoid this, or just re-trim every time?

I don't know. I have two 1000mah 25C batteries and one 800mah stock battery. I can't tell much difference between them other than the bigger batteries being a little heavier. I still seem to get altitude and speed, it just takes a little more to get it off the ground and is just a touch sluggish because of the weight.