Choosing the right battery

I have been buying the battery 4S 30C with over 2200 mah but I would like to know if I am getting something too powerful and get something with less weight but at the same time with more mah.
My drone is a hex copter with:
jDrones 30Amp ESC
Jdrones AC2836-358 880kv motors
Because I have a 30 Amp I chose the 30C but it seems my motors can drain up to 20A ( I am wrong? ).
With these information, can I get a 25C without any problems? Should I stick with 4S or going for a 3S?

@max246,
Since you are having to power 4 motors and not 1 at once, I would stick with at least a 30C and up battery and I would pick at least a 3300 to 4400mahr battery if you want descent flying times. However if your multicopter is small, I would go with the biggest battery that it could reliably carry.
Regards,
TCIII Admin

What about the voltage of the battery? Better a 3S or 4S

@max246,
Over on the DIY Drones sister site, the mulitcopter members seem to fly with both sizes. It seems that you cannot move between the two sizes without retuning your multicopter.
Regards,
TCIII Admin

@max246

I have the 880kv motors with 11" props on the 3DR QuadCopter and tried to make use of the 3S 2200mAh 30C batteries I already owned. I soldered up a parallel connector and lashed two batteries together with long velcro strips. This keeps the voltage at 11.1 while doubling the mAh to 4400. Plus the extra weight helps with the over-powered 880kv motors.

@TCIII

I was browsing through the 3DR store and noticed they offer a T plug adapter. Looks like what I rigged up.
store.3drobotics.com/products/t-plug-adapter
That’s a parallel adapter, right?

@Daedalus,
Yes, that would allow you to connect two batteries in parallel.
Regards,
TCIII Admin