westend wrote:
I'm betting that your ground wire for the DC system is not up to the task. Using an 8 AWG ground,with 4 batteries and an inverter trying to pull +1500 watts, the inverter is seeing a low voltage condition. Your use of an extension cord may be just enough to allow some capacitance to overcome the inverter's bad feelings about the situation.
The frame ground from the inverter is just as MrWizard has stated, a protection and interference device, not part of the power profile.
The frame ground and the DC negatives are separated in my system. I apologize if I made it sound as though they are connected together - they are not. I have the frame ground for a few pieces of equipment (solar panel, inverter, charge controller) connected together with #8 cable, but they are totally separate from the power system.
The DC negative is actually a 2/0 cable, not a #8 cable. This is not a low voltage situation. The trimetric shows that the 4 batteries can easily maintain voltage above 12.0V with the microwave running and the inverter does not show a fault when the trip occurs (it would on a low voltage).
