You will gain a longer flight times from a 4s battery if the ESC / motors will work with the extra few volts, please check before using!
The interesting point about adding more and more batteries is the additional weight, so one battery, say a 4s 6000 mah would give you a 8-10 min's of flight time, add the same battery again so you have two now which is double the power however double the weight!
As the power to weight ratio has increased you will not get a 20 min' flight time, it would be closer to say 12-15 min's. These figures are for illustration purposes only and the real flight times will change in the real world, the optimum set up is the most powerful battery set-up for the least amount of weight!
I hope this help you :)
what whould be the best batt. arducopter stock esc ac 2836-358 880 kv mtr. 12 45 props thanks
Thank you! That did clear up some details I couldn't quite work out like increasing the number of cells instead of mah. Thanks again!
hello felix I have one on the way and I have the same question what whould it be a 4c 3000 4000 5000 ? I whould like to order some nano techs lightest I think but whould like to know which size whould be best thanks