Calculate the approximate time required to recharge a battery based on capacity and charger output current. Includes an efficiency factor for realistic estimates.
Charging is not 100% efficient. Some energy is lost as heat. Also, the final 20% of charging (CV phase) is much slower than the initial bulk charge.
Usually yes, but check your battery's max charge rate (C-rate). Charging too fast can overheat and damage the battery.
Add 20% for efficiency.