TC200-CAN-BP-827-i-TDM Two-Position Battery Charger with TDM for Canon BP-800 Series features two integrated battery plates supporting Canon and non-OEM generic BP-827, BP-828, BP-819, and BP-820 batteries. It's capable of charging two batteries simultaneously and charges a typical 2670mAh battery in about 3 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. A built-in Test/Discharge Module (TDM) will allow you to determine whether a battery is new or old and on par with its label. TDM cycles the battery (fully charges and discharges it) and provides a report on its capacity. An auto-detecting USB port is available for charging phones, tablets, and other USB devices. It works when the charger is plugged into AC power or on-the-go off of an attached battery.