Battery charger

A device with power factor correction for converting three-phase alternating-current power into direct-current power for charging a battery, comprising:

• a DC to DC power converter having a positive input, negative input, a positive output and a negative output;
• a positive lead in electrical communication with the positive output of the power converter and connectable to the positive terminal of a battery;
• a negative lead in electrical communication with the negative output of the power converter and connectable to the negative terminal of the battery;
• a first set of three diodes, each of the first diodes having an anode and a cathode, each cathode of the first diodes in electrical communication with the positive input of the power converter, the anodes of the first diodes connectable to an AC power source in a first, second and third phase, respectively;
• a second set of three diodes, each of the second diodes having an anode and a cathode, each anode of the second diodes in electrical communication with the negative input of the power converter, the cathodes of second diodes connectable to the AC power source in the first, second and third phase, respectively;
• an input capacitor connected to the positive input of the power converter and the negative input of the power converter;
• an input resistor disposed between the anodes of the second set of diodes and the negative input of the power converter;
• and
• a differential amplifier having an inverting input connected to the anodes of the second set of diodes, a non-inverting input connected to the negative input of the power converter, a negative power voltage connected to the negative input of the power converter, a positive power voltage connected to the positive input of the power converter, and an output connected to the power converter driving the power converter such that the sensed current at the inverting input and the non-inverting input is proportional to the voltage across the positive power voltage and negative power voltage.