(battery capacity(mAh)/1000*3.7) / (input current*input voltage) * 1.5= charging time (h)
e.g:
How long will the Astro 5600mAh battery can be fully charged via 5V/1A adapter?
(5600ma/1000ma*3.7v) / (1A*5V) *1.5 (loss rate) = about 6 hours
No, the charging time can't be calculated by such simple formula since there are 3 charging modes during a full charging, they are pre-charge mode (typically when cell voltage is below 3.0V), the constant current (CC) mode (cell voltage between 3.0V ~4.2V) and constant voltage (CV) mode (under this mode, the charge voltage is fixed at 4.2V, the charging current is decreased gradually to the end of charge current). Your calculation method only be correct under CC mode, so the charging time is longer than using such formula calculated time.
Full power standing time (months)
battery capacity(mAh) / (battery quiescent current + cell capacity * cell quantity / 14400h) /24h / 30d =Full power standing time (months)
e.g. A1271, capacity 20100mAh，battery quiescent current 0.1mA，cell capacity 3350mAh，cell quantity 6pcs .
full power standing time is 18.66m (18-19m)
the full standing time is related to quiescent current , cells' configuration and cell itself quiescent consumption, e.g. A1271, it has 6 3350mAh cell with the configuration is 2 cells in series and 3 cells in parallel (2S3P), that the actual cell stock is 10050mA/7.4V; the PCBA quiescent current is 0.1mA, so in theory, after the portable charger is fully charged , the standing time is: 10050mAh/0.1mA/24hour/30=139months. Please be noted the actual standing time is more less than this calculated time since the calculated time didn't include the cell itself power dissipation, and the cell dissipation is related to cell voltage, storage temperature, etc.