I want to sense the current into a 84 V battery while charging and disconnect it when fully charged using a MOSFET. Is it advisable to use lowside current sensing? I used a noninverting opamp configuration shown below but the MOSFET started smoking so I quickly turned it off.
Am I right in assuming that the power losses while the MOSFET is conducting is the voltage difference between the drain and source multiplied by the current flowing through it? The charging current is 5 A. Please help me out. The part of the circuit on the left of the MOSFET is for ensuring that the gate voltage is 12 V and the 16.8 ohm resistor represents the battery being charged. It is a lithium ion battery with its own BMS I just want to use a single charger to charge multiple batteries one at a time and disconnect each once full so I am using this circuit externally. Please assist me debug my circuit. Thanks.