Method, apparatus, and computer program product embodiments are disclosed for estimating the remaining charging time of a rechargeable battery. An example embodiment of the invention comprises a method comprising the steps of detecting an availability of a charging device to a battery in an apparatus; determining a type of the charging device by measuring its charging characteristics for charging the battery in the apparatus and comparing its measured charging characteristics with stored charging characteristics of a plurality of chargers, adapters, or charger-adapter combinations; measuring charging current of the battery; and calculating a time remaining to charge the battery based on a comparison of the measured charging current with the stored charging characteristics.