I have been running my system with two arrays for a few months now. I thought I would post a few photos of it's operation. The two arrays are 4.4 and 4.9 kw for a total of 9.3 kw stc.
This first photo shows the system. The two Classics are 150s. I divert excess power to my hot water tank using AC and a Crydom Evolution Dual relay. The inverter on the right is the diversion inverter. The center and left inverters are the load inverters. The diversion inverter is also the charging inverter. I can supply full load with my load inverters while charging. The logic is - If I need to charge then I do not have enough power to divert. This system lets me use a small generator that runs at an economical speed while also supplying all my loads. The hot water tank has 2 2kw elements in it. They can operate simultaneously. The diversion control first maximizes out the lower element and then turns on and maximizes the upper element (Paul - Thank You for this idea).
The diversion control diverts if the amperage coming in to the batteries, measured by the WBJr, exceeds setpoint (presently 65A) and also diverts if the voltage exceeds the divert voltage setpoint (presently .3 V below the Classic setpoint) when in Absorb, Float or Float Mppt. Amperage diversion at this time is done using the upper element in the tank. Voltage diversion starts with the lower element in the tank. All diversion setpoints change when the Classic setpoints are changed. The control reads the Classic and then adjusts the diversion control setpoints. The control also dynamically limits the amps flowing to the batteries, once again measured by the WBJr. This presently set at 70A. There are 2 megas in the diversion control. The first operates the 4 PID controls (Amp diversion, Amp limiting,Voltage diversion 1 and Voltage diversion 2) and displays on the two left hand and upper right hand 4X20 LCDs. It interfaces with the left hand Classic 150 (#10). The second mega interfaces with the right hand Classic 150 (#11). It also has the thermostat function and the does addition of KW and W from both arrays. It runs the lower right hand LCD. Both Arduinos read and write to each other using a serial without blocking system. It is not lightning fast but works well.
Will