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• Detects when the Charge Controller activates the diversion load resistors by sensing voltage, then closing the relay contacts. Otherwise, this device is dormant and the relay is Open.
• Once triggered, the device closes the relay, and stays active for a pre-set time, then shuts off.  If the Charge controller is still running power through the diversion resistors, then the device triggers again for another cycle.  The activity cycle can be adjusted.  Let's assume between 15 minutes and 1 hour, for now.
• The relay only supplies + battery voltage to the DC positive terminal of the microinverter. 
• The DC negative terminal of the microinverter is grounded through a pair of power resistors, totaling 4.5 Ohms.
• Even so, the microinverter should begin to activate as soon as the relay closes.  At first the microinverters will not pass any DC current, just measure DC voltage, so it won't see a voltage drop across the power resistors, yet.
• Microinverters always have a 1- or 5-minute delay before they actually connect to the AC, so the device will just wait in the meantime.
• While waiting, the gate driver is already active.  What it's doing is cycling the FET on and off across the 4-Ohm power resistor.  I'll explain the reason for this later.
• Once the Microinverter comes on-line, it will simultaneously connect to DC, admit current through the DC lines, connect the AC output lines, and  start seeking the MPPT point.  Since it's pulling DC through some power resistors, it will detect a voltage drop.
  This is intended because solar panels have a strong voltage drop while current increases.
• Unfortunately, if only power resistors were used, the MPPT algorithm in the microinverter would measure higher power at ever-increasing current.   Is 10 Amps enough? 10 Amps X 40V is 400W, great.  Is 11 Amps enough? 11 Amps X 39V is 430W, better... and it keeps doing this, until it exceeds its own power rating (and/or catches fire).  Microinverters are designed for solar panels only, and the "knee" of the curve keeps them safe.  I don't believe that the microinverter will self-limit (but maybe it can).
• To keep the microinverter from blowing itself up, I've introduced a FET shorting across the 4 Ohm resistor.  By doing this, the voltage drop can be controlled and simulated, like a PV panel was there.

• When the FET is on, the current is basically shorted to ground, which is like the typical use of most N-channel MOSFET controls for motors and heaters.  The microinverter will see lower resistance and current can increase.  Left to its own, its MPPT will seek more current to increase power output.  This simulates being on the right side of the knee of the PV Panel I-V curve, increasing current and voltage will drop slightly.
• When the FET is off, the current admitted by the microinverter is subject to a lot of voltage drop, so much that there is a strong voltage drop.   Now the MPPT algorithm will measure lower voltage and determine that the input power is dropping, thus the current is too high.  This simulates being to the left the knee of the PV Panel I-V curve, where voltage has dropped due to more current.

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