Hybrid BLDC ESC & GX25 ECU

I have advanced my thinking about the power train. More specifically the details for the board that will handle generator stage has converged somewhat. This is the current idea:

• Use Brushless DC (BLDC) motor as both starter and generator connected to Honda GX25 motor.
• Build a simple DIY ESC circuit that when powered will rotate the BLDC shaft to start the GX25 (working as a starter motor).
• Build a rectifier circuit that when engaged to BLDC will make it generate power for charging batteries and giving the robot an extra power boost in the hour of need.
• Build an ECU circuit with inputs for tachometer, voltmeter, ammeter and outputs for throttle servo and mechanical relays that allows engaging/disengaging the ignition, ESC and rectifier circuits on demand.

GX25 BLDC generator

The basic API for the circuit should look something like this:

• Low-level
• Start engine
• Stop engine
• Set throttle
• Set charging
• High-level
• Start generator only when battery is low and/or power drain is high
• Adjust throttle to accommodate load
• Detect, alert and manage overheating
• Detect, alert and manage low-fuel
• Manage motor warm-up under different ambient temperatures.

How this circuit will communicate with central command and what will happen when communication breaks down is still to be decided.