hey there, suggest me a lipo for my new Ax2810q pancake motor(900kv) quad

my auw would be around 1800gms max, so i'm not in need of ample thrust, so i'll maybe hang a 10 or 11 prop
but the motors are power hungry, drains a max of 25-29amps, 18.5 in my case (11prop and 3s batt.)

now how do i choose a proper amp and discharge rate?
wattage in my case=205w
max possible wattage=370w

my case 4x amp draw=18.5x4=74a
max amp draw(with 4s and 12 prop)=120a

i need a batt. of 3ah+ 30c+, or even more? what should be the margin? 3ahx30c=90a=safe? 3ah 20c=unsafe?

http://www.quadkopters.com/product/brushless-motors/ax2810q-900kv-brushless-motor/
here's a link to chart
my goal is to keep mah rating low

At 18.5Amps per motor, your setup will consume a max of 18.5x4 = 74 Amps
A 3S 2200mah 40C would be fine which can provide a max of 88Amps Constant

If you would like to keep Capacity even lower, you can look at MultiStar Race Spec 3S 1400mAh 40-80C Multi-Rotor Lipo Pack For FPV Minis.
This will provide a constant of only 56 Amps which sure is less than the max that your motors can consume. But the Burst Ratings goes up to 112 Amps.
If you don't intend to do uber aggressive flying and the priority is to keep the weight as less as possible then this LiPo should be the perfect from the lot.

Needless to say, the more you stay close to the max ratings of a LiPo, the faster it degrades.

2.2 40c looks fine to me, thanks bhavesh,

these motors are over kill for payload, but are very much power hungry, what do you thing the flight time possibly could be? ofcourse with 2.2ah 40c and mentioned specs?

as my auw will be 1800gms the remaining thrust should get a better flight time right? how does then apm draw even matter?

Roby, Well to me 18.5 Amps at 11.1Volts at full throttle doesn't sound too much.
These infact are quite efficient motors as per the thrust that they generate.

Assuming an average consumption of 40% of the rated amps (You don't fly at full throttle all the time) your complete setup would consume ~30 Amps which should get you about 4-5 mins of flight time.
Of course the flight time will vary according to many factors like how well the FC is tuned, flying conditions, flying habits, etc

If you will be flying steady and need more flight time, why not get a Multistar 3S/5200mAh which is only 124 gms more heavier than a Zippy 3s/2200/40C. This Multistar should get you substantially more flight time since you will be increasing the capacity 2.3 times within minimal increase in weight.

12 min on a 5ah 3s, worth trying, thank you IHS

You're welcome. 

One thing you will have to watch out for with MultiStar LiPos is their low discharge rate. The 5200 mAh  is only 10C so it can supply a max of 52 Amps.

Is there a possiblity you can try 4s setup? Higher payload and 3s setup are less efficient. 4s, 6s are best when you need higher payload or longer flight times. 4s setup will run much cooler too. Take ur motor spec and see the amp draw for 4s setup, then go for a lipo.