I'm using a GSM device powered by a battery, charged from energy harvesting from a low current source (0 to 200mA, the most of the time 20mA @ 9V.)
To charge the 8000mAh 4.2V battery, I'm using a TP4056 with previous buck (after some tests with buck-boost charger I found this configuration more efficient,) and the device is full most of the time if device works as expected.
Right now the TP4056 chooses when to charge: would it be better if I will force discharge a little bit more before charge? What can be the estimated battery lifespan retaining full battery all the time (with a few charge/discharge?)
Would it be any better if I limit (lower) charging current?