formula:

mtfc (10% efficiency loss) = ((bc / crc) * 11) / 10

mtfc (20% efficiency loss) = ((bc / crc) * 12)/10

mtfc (30% efficiency loss) = ((bc / crc) * 13)/10

mtfc (40% efficiency loss) = ((bc / crc) * 14)/10

mtfc (inefficiency loss) = ((bc / crc) * 10)/10

here

mtfc - maximum charging time

bc - battery capacity

crc - charging current