Combining Solar Panel Strings facing different directions - Virtual Tracking
When combining strings with a different azimuth in an off grid system, lets say NNE facing with North Facing and NNW facing (Southern Hemisphere), you catch the morning and evening sun better, this is called "Virtual Tracking" where fixed panels can start charging the batteries sooner and more effectively in the morning and can manage the load for longer without draining the batteries in the evening, thus enabling your battery operating window to be shortened.
Now my question is regarding the electrical characteristics of this practice, if you were to combine the panel strings facing in different directions in the same sub-array, combiner and charge controller, 1-combiner = 1 charge controller for off grid.
One assumes that each panel string (i.e. the ones facing different directions) produces a different current output at the same voltage, if this is the case, I guess their is no problem (although at the very start and end of the day, the voltage might not be the same which could cancel out the benefit of doing virtual tracking in the first place).
I guess that if the panels facing different directions (Azimuth) were grouped together on the same combiner and charge controller (i.e. different directions use a different combiner and charge controller pair), there would be no problem and EVERYTHING is telling me that this is the only best practice way to implement virtual tracking to avoid imbalance and any electrical back-feeding between the panel strings.
Lets assume three ±45Voc panels are in each string and three strings are combined into one 150V MPPT charge controller, e.g. Outback FlexMax 80, what is going to happen electrically if we mix strings with panels facing different directions, i.e. one facing North, one facing NNE and facing NNW, in the morning the NNE panel string is going to wake up the charge controller before the N and NNW panel are electrically active and the CC will then perform MPPT calculations using the NNE string only
Then their is the issue of potential voltage imbalance during the early morning hours between three strings on the same combiner to consider while the N and NNW facing strings get their electrical activity ramped up from zero to the Vmppt level.