VARTA | Eco Charger For Rechargeable Batteries in 4 AA/AAA | AVAVA57680101Enables you to charge different numbers and combinations of cells Method which takes advantage of the fact that the cell voltage reduces slightly in a rechargeable battery ( Delta V), as soon as the cell is completely charged Contains criteria for switching off to prevent charging of primary cells, defect cells or cells with reverse polarity Prevents the natural self discharging process of rechargeable cells