I am building a relatively simple circuit which essentially consists of two lead acid batteries rated at 12V and two motors rated at 12V. My original plan is to wire them all in series, and control them with a motor driver of some sort using a pwm signal. However, all of the motor drivers I can find that can handle this are rather expensive, and it seems as though it would be just as acceptable to do it with one or two mosfets. I am not sure of what quality/type of mosfet to get, and where to place them within the circuit. I am thinking it would be easiest to do just one high quality one before both motors, but would I be able to control the speed of the motors using a pwm signal that way though? Any advice is appreciated.
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The motors rated power is 337 Watts (at 2655 rpm, 172 oz-in, and 68 amps). The load is present at all times, and should stall minimally, but I have a current sensing ic in place to monitor the current and reduce the voltage if it starts getting too high. I don't care too much about bidirectional control, and the current measuring circuit is a 180 A rated attopilot chip.