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Is there any way to tell the health of a LiPo battery?
There most certainly is. Let me tell you about battery IR. That stands for measured internal resistance. "Internal resistance testing is a relatively simple way of measuring the health of your LiPo batteries. Internal resistance is the electrical resistance that occurs inside the battery cells themselves as the battery creates electricity. The higher the internal resistance the less current can flow from the battery to your ESC and motor." https://www.flitetest.com/articles/LiPo_Battery_Internal_Resistance_Testing
How do check the IR of a battery?
Check your battery charger manual to see if it gives an IR reading when a battery is connected (both power and balance leads). Temperature of the battery should be consistent. This value can be used as a starting point in determining health. The IR will increase as battery charge cycles increase. Batteries that are puffed will have a higher number.
Following are the measured IR values on two Ovonic AIR 2200mah 50C LiPo batteries that are relatively new: 19 and 13 mOhm. A puffed battery can be over 100. These values will increase as battery charge cycles increase. A good primer on LiPo batteries: https://rogershobbycenter.com/lipoguide