I have scanned the forum & not found a satisfactory conclusion on battery life. I have a 2015 I1P v1 & 2017 I1P v2, 10 batteries including the 3 yr old originals with between 80 & 100 cycles. The Battery Life is registering close to 80% on some. I deep cycle all batteries after 15 to 20 cycles using the Phantom Angel. They all look good, charge to 100% & no bulging or cracks. I quite often get a big drain on one cell, occasionally a low voltage warning according to the Healthy Drones database. My question is when is it prudent to retire a battery? Is 80% battery life time for retirement? I’d rather buy a couple of new batteries than risk the drone shutting down when I do a quick maneuver.