Decided to run one of my batteries thru a discharge analysis on my Hyperion EOS 0720i. From my research, I decided that a good estimate for a battery's capacity is to start fully charged (4.2V/cell or 16.8V) and discharge at a slow rate (I used 0.5C) to 3.2V/cell (12.8V). Some information suggested 3.0V/cell at 1/5C, but I felt that 3.2v/cell was a safer level, and I didn't think that the difference between 1/5C and 1/2C would make all that much difference. I entered the battery's capacity as 5400 mAh as per the label on the battery, set the discharge to terminate at 3.2v/cell and a discharge rate of 0.5C (2.7A) to determine where the dropoff was, and where on that curve, the ST-16 is first giving it's warning (14.7V for me). Below is the discharge curve. Several things immediately pop out. One is that Cell 1 terminated the discharge at 3.2V. The other cells were all higher with Cell 4 150mV above Cell 1. Most importantly, and strangely, is that the battery capacity seems to be much, much higher than specified by Yuneec. Mine came out about 17% higher at 6300 mAh. I ran this test twice just to verify I didn't screw something up. With a capacity of 6300 mAh, the 80% point corresponds to a pack voltage of 14.8V (close). Is it possible that the packs are being under rated? I will repeat the test when I get my Western Mountain Radio CBA IV. Also, I have a new motor coming to run some wattage and thrust tests with the Yuneec provided prop and others for comparison. Once I have that number, I can better estimate the system draw at 50% throttle, and given the flight times (16:40 for this pack), I can get another estimate of capacity used.
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