Ok, I think I understand how this Precision Circuits PCS system works. I spoke to Winnebago Technical support and George Cepynsky at Precision Circuit, I think he is the owner – a very nice guy. Winnebago’s knowledge on this system is only superficial, George designed it.
First you have to define a load as understood by this system; there are loads which can be shed and there are user loads. Loads that can be shed are factory defined and there can be a maximum of 7. In order of first shed loads in my coach they are, 1)Engine Heater 2) Water Heater-AquaHot 3)Front A/C 4)Rear A/C 5)Middle A/C 6)Dryer 7)Washer. These shed-able loads can only be changed by the factory.
User loads are all the other stuff, in my coach they are RR, Dishwasher, Microwave, Fake Fireplace/heater and of course the Inerter/Charger. User loads are never “shed”, as George said, we don’t want to prevent you from popping your microwave popcorn. If I am on a 30amp service running 2 a/c units at 28amps and I turn on the microwave, 20amps, my 2 a/c units will be shed. George said the “bad guy” in this 30amp situation is the RR, it is normally drawing 6amps leaving only 24amps to run the 2 a/c’s.
Enter the “Inverter-Assit” feature of the PCS, its purpose is to “provide additional power from the battery bank to smooth high peak demands”. Here is where things get tricky. The Precision Circuits PCS works closely with the Magnum Energy MS Series Pure Sine Wave Inverter/Charger and the Magnum Energy Inverter Remote Control. The PCS will draw additional current from the Inverter/Charger as long as the “Low Battery CutOut” setting, established by the Magnum Remote control, has not been met.
So here is how it works; I am running on a 30amp service, I am drawing 28amps to run my 2 a/c units. Suddenly the RR cuts on drawing 6amps, I am now at 34amps. The PCS system immediately directs the Inverter/Charger to supply the additional current so the 30amp threshold will not be met. The PCS will continue receiving the additional amps from the Inverter/Charger until it senses the “Low Battery CutOut” voltage has been reached. When this LBCO has been reached the PCS will begin a battery charging operation and shed loads (my second a/c) until the 30amp threshold has been reestablished.
The LBCO can be set at 9, 10, and 11 volts, my coach is set at 11 volts. Next time I have this problem I am going to set the LBCO to 10 volts and see if that helps. If not, I know where the RR circuit breaker is located.