Do you purchase them on a yearly basis? Do you replace on a set schedule or do you replace them as needed? Just curious as to everyone's thoughts...
I'm still flying on all my original LiPos. I have 7 matched pairs of 8000 4S (14 in total). 2 pairs are QP8000 and 5 pair are Zippy 8000. I have 30-40 flights and/or charge/discharge cycles on each battery. None has failed me yet. They're 10-15 months old. I fly them in parallel and carefully monitor voltage before and after each flight. My flying typically results in almost exactly 1,000 mAh of battery drain per minute in the air, and I never fly long enough for the lower power warning in the MK FC to sound...usually I'm back on the ground within 6-8 minutes. So to answer your question, once I start to see any level of decline in either battery in my pairs, I'll retire both of them. But I don't anticipate the "quit while you're ahead" approach.
Hey Steve, I'm in the Bay Area like you. We've had some pretty cold days and nights lately. My lipos sometimes have significantly shorter flight times when it gets in the 40 degree range. Have you or anyone else noticed that? Especially lipos that I charge the night before and leave in the garage. jim
My understanding of LiPo temperature issues is that they don’t lose charge in cold weather, but they definitely don’t perform as well. The goal is to keep them near room temp. while waiting to fly. Once in the air, they’ll warm up.
We flew a couple batteries this past weekend and it was 38 degrees outside... 6S 5300mah lipos and got 7.5 minutes per flight with our GH3. Flight characteristics seemed standard across the board compared to warm weather flights.
I'm alot more careful after my recent experience: I had 2 batteries go from 18.6 to 14v in under 30 secs, one went to 9v (confirmed on the SD card). They were both about 1 year old, one Quadrocopter, one a Zippy. I never charged over 1c and fly pretty gently most of the time, and never much under 14.5v. They ended up charging up fine, but they did it again, but I didn't push it. I think it was just coincidence that it happened the same day, they both had similar amount of flights. Thought it might have been a short but everything since has been fine. I was freaked this could even happen. I now take off, hover for 10-15 sec, and check the voltage before I fly my "mission". http://forum.freeflysystems.com/index.php?threads/voltage-16-8-to-14-in-30-sec-flat.2505/
Well jim thats plain chemistry, lower the temp and every reaction slows down. Try keeping ypur lipos at roomtemp, I think thats what one can do. Best regards. /Janne