TC400-SON-FW50 Four-Position Battery Charger for Sony NP-FW50 batteries features four integrated battery plates supporting Sony NP-FW50 and non-OEM batteries. It's capable of charging four batteries simultaneously and charges a battery in about 2 hours. As a battery is being charged, a diagnostics LCD displays status in volts, amp hours, and percentage of charge. The percentage of charge is estimated using a proprietary algorithm.