Our Nikon USB Battery charger can charge your Nikon EN-EL20 rapidly in 1-2 hours. The charger is design in such a way to prevent your battery from overcharging and short circuiting. The charger has an LED Display which displays Charging bars to let you how much it has charged, much better than waiting for a light to change colour. when it displays 4 cells that means battery is fully Charged. Our charger is Light-weight which means it is easy to carry it on a Long Journey.