There are a thousand variables to the "Battery Question" but I was wondering if there is any insight that someone could provide me about a consistent issue I have had. I purchased a standard Quadrocopter Octocopter about 18 months ago. Built it and everything was great for about 4 months. I have always flown with a DSLR (7D). I never worried too much about flight times as they were in the 4 or 5 min range with single 6200 4S battery. The day after I flew a 700S camera (which I knew was too heavy but flew great for the whole day) I was unable to get a single battery to fly my DSLR for more than 90 seconds. At that point I began to fly dual batteries and was getting the original fly times again. After, I found that the batteries would loose voltage at a fairly standard rate but the amps that were used never were more then about 30% on each battery. This went on for about 5 or 6 months at which point the times began to diminish while the amps being used became less and less. I then built another copter that a friend didn't know how to finish. From the get go I ran dual batteries and still only got approx. 4 or 5 mins of flight. Soon this too diminished to less then 3 min. I needed to find a way to get the copter to stay up for 5 or minutes so I took a chance and this time used 4 batteries at the same time. Yep a total of over 24 amps on top of the copter. The amazing thing was that the copter flew for a total of nearly 8 minutes at a total weight of 24lbs. and yes the motors were hot but what was even more interesting was that the batteries used nearly 70% of the amps. I have now built a "Heavy Lift" copter using the Tiger 3520-11's with Castle Talon 90's and the DJI-Wookong-M system. I have now purchased 4 FreeFly 9000maH 6s Batteries. I am using them in pairs. I have now flown a half dozen times and each time the voltage drops to 22.2 in about 5 to 6 minutes (which would be fine) but never uses more then 30% of the amps in the batteries. So here is the question based on my limited observations. Why is the Voltage dropping so fast that the batteries are unable to utilize more of the amps? I did attempt as single battery flight and was only able to fly for approx 90 sec. which resulted in the voltage dropping to its lowest safe level and only using 10% of the amps available from the battery. It would seem that if I employed more batteries with lower amps ratings (for instance 4 6S 5000maH batteries) might make the voltage last long enough to allow the amp draw to become more within normal levels. What are your thoughts about this? Is there anything that you have seen that is similar? How is my logic flawed so that I could possibly get a more lengthy flight that uses the batteries maH to the "normal" levels of up to 80%. Thank you for your time and insight.