I'm using a TP4056 to charge a 18650 (branded Samsung, 2900 mAh) that powers a small DIY weather station.
The weather station is equipped with a MAX17043 that measures the charge of the battery, at the moment the station is not powered with solar panels but when the battery charge goes lower than 20% I disconnect it from the station and charge it separately with a TP4056 board and a 5V 3A power supply.
I'm doing this since february '21 and until a few weeks ago the blue led of the TP4056 turned on correctly at the end of charge (the MAX17043 measured 95/96%).
Now when I connect the battery, the red led correctly turns on but after about 3 hours the blue led turns on while the red one remains on.
The first time I disconnected the battery from the TP board and connected to the weather station: the measured charge was around at 80%.
Then I attached the battery to the TP again for 1 more hour but the both leds remained on, just a few hours ago I recharged the battery and this time the charge measured from the MAX17043 was 56% that turned to 60% after 30 mins.
Why that behaviour?
TP4056 board defective? Damaged battery?
Thank you, regards.