recently, for a project, i need to provide an auxiliary power unit, since required power demand is not high, i decided to go with a 1200mAH 18650 li-ion battery with TP4056 charging module and HW-432 Voltage step-up module (to provide 5v needed for the project).
If i connect the 5.5v input voltage (since there is 0.5v voltage drop because of the D2 schottky diode [SS34]), everything works fine, when the input voltage is cut, battery kicks in and again everything looks good, until battery is fully discharged! after the when i connect the 5.5v input voltage, it draws around 80mA forever?! after waiting for a good 20H, i connected 4.2V (limited to 1A) directly to the battery for 1 minute and now it charges the battery with the current around 1A as suggested in the datasheet. so could someone please tell me what is wrong? perhaps the battery is faulty?