Features: Professional Li-ion/Ni-MH battery charger with three optional charging current (0.25A /0.5A/1.0A) Charge four 10440/14500/14650/16340/17500/17670/18350/18500/18650/18700 Li-ion batteries and AAA/AA/A Ni-MH batteries or two 22650/25500/26650 (3.6V/3.7V)Li-ion batteries and SC/C Ni-MH batteries simultaneously but respectively 0V battery activation Reverse polarity protection and short circuit protection Battery-type recognition For different type of batteries, XP4adopts different charging methods: for lithium batteries, XP4 adopts three-stage charging (TC, CC, CV); Ni-MH batteries, XP4 adopts pulse charging and 0△V,-△V judge method plus stopping charging when overtime and over voltage function USB Output (Synchronous-rectified method) The built-in USB output with low voltage, overload, short circuit, overheat and reverse-polarity protection plus stopping supplying when low voltage For Ni-MH batteries, XP4 has the discharge function to repair the battery capacity Adopts PWM technology to control the high efficiency DC-DC circuit, lower the voltage and reduce energy loss Charge four 10440/14500/14650/16340/17500/17670/18350/18500/18650/18700 Li-ion batteries and AAA/AA/A Ni-MH batteries Or two 22650/25500/26650 (3.6V/3.7V)Li-ion batteries and SC/C Ni-MH batteries simultaneously but respectively