Man my charger when i take it to the field and it runs off my truck batt. it takes seems like forever for it to charge anything. It takes it while to charge plugged into wall but not nearly as long as at the field. Maybe it is because I have nothing to kill time and just notice it more. Very seldom do I even take it anymore as i keep my batteries pretty much charged all the time. Most times i start charging again as soon as i get home. But there have been times i have not charged in over a week and still fly with no problems. But the Voltwatch keeps me in the know enough not to worry to much. If batteries do adapt memory mine should really never go down lol. The should remember they are charged up and stay that way rofl.