Until recently I only used the Yuneec "smart charger" that came with my Q500+. I really knew nothing about internal resistance and how it could affect battery and flight performance. I have Q500 5400 mAh batteries that are at least 5 years old. I now have an Onyx KX80 multi-chemistry charger that does all kinds of batteries and tests. I recently tested an old battery that came with my first Q500+ for internal resistance. I had made 4 flights this past summer and got good(not great) times from the battery. The readings for the 3 cells were... 17, 21, & 30. The battery is not puffy. I ran the battery down some in one of my Q's and then placed it on the new charger and set it for "storage" mode. When finished, I disconnected it and let it sit for about an hour and ran the resistance again. This time I got readings of 17, 20, & 28... some had actually gone down. Over the next 2 months I plan to weekly charge up and then discharge it for storage the following day. I want to see if the resistance readings go lower or higher over the time period. I'll provide updates to this post.
Update Nov 14, 2021... readings are now 17, 21, & 29. I plan to do two balance charge and storage runs before my next report.
Update Nov 21, 2021... after another charge/storage cycle readings are 17, 20, & 26.
Update Nov 24, 2021... after another charge/storage cycle, readings are 17, 18, & 24.
Update Nov 25, 2021... readings are now 17, 17, & 24.
Update Nov 28, 2021... On this day I fully charged the battery and decided to use it in a flight. I made it off the ground and about 15ft in the air and I got a red warning banner on my ST10+ that said battery depleted land immediately. I never got any other low battery warnings. It just went from showing a good 12.2 volts to nothing in less than 10 secs of flight time. The props were still spinning and I was able to safely land the A/C. I shut everything down and then restarted all and the battery again showed 12 volts. I started another flight and the same thing happened. Voltage went from good volts to no volts in about 10 secs. This tells me that this battery will simply not hold any meaningful current and it's time to retire it. The battery has given me about 5 years of good service.
Update Nov 14, 2021... readings are now 17, 21, & 29. I plan to do two balance charge and storage runs before my next report.
Update Nov 21, 2021... after another charge/storage cycle readings are 17, 20, & 26.
Update Nov 24, 2021... after another charge/storage cycle, readings are 17, 18, & 24.
Update Nov 25, 2021... readings are now 17, 17, & 24.
Update Nov 28, 2021... On this day I fully charged the battery and decided to use it in a flight. I made it off the ground and about 15ft in the air and I got a red warning banner on my ST10+ that said battery depleted land immediately. I never got any other low battery warnings. It just went from showing a good 12.2 volts to nothing in less than 10 secs of flight time. The props were still spinning and I was able to safely land the A/C. I shut everything down and then restarted all and the battery again showed 12 volts. I started another flight and the same thing happened. Voltage went from good volts to no volts in about 10 secs. This tells me that this battery will simply not hold any meaningful current and it's time to retire it. The battery has given me about 5 years of good service.
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