When I charge my battery at a constant voltage and current, the energy supplied is constant throughout the charging process. If it takes 1h to charge to 80%, the next 20% takes another 1h.
Since I supplied the same amount of electrical energy during the first and second one-hours, is a significant part of energy wasted during the second one-hour?
I understand the battery internal resistance increases by the degree of charge. Does it mean we waste a significant of the electrical energy supplied in the form of heat?