Two-Position Battery Charger with TDM for LP-E8 (for Canon EOS Rebel T2i, T3i & T4i) batteries features two integrated battery plates supporting Canon and non-OEM generic LP-E8 batteries. It's capable of charging two batteries simultaneously and charges a typical 1120 mAh battery in about 2.5 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.