I thought I knew how MPPT works, but now I'm in doubt. I have a situation where my north-facing panels only get sun starting mid-morning and lose it mid-afternoon. I have a place that I can mount east and/or west facing panels and connect them to my MPPT2 interface (Sunsynk 5.5kw). But now I'm wondering. As I understand it, if I connect the string half east and half west facing, the out-of-sun bank will kill the whole string. Would I be better off putting them all facing the same direction (east or west)? I have the battery capacity to see me through the non-productive period.

Best is to choose one orientation of panels per MPPT. According to time of day you are most likely to need the power. But consider that facing North is usually producing best, and mid morning to mid afternoon is exactly peak generation time. Might be that the current losses of early morning and late afternoon are comparable to the losses of facing East or West. Something that can be resolved by trimming down a tree or two?

I've kind of run out of space for north facing, unless I mount the panels almost horizontally. But I look at the sun as it goes west and I think "you know, that's a real waste of photons"  

12 hours ago, farmer barnes said:

As I understand it, if I connect the string half east and half west facing, the out-of-sun bank will kill the whole string

That is correct, but only if they are all in series.  If you have the strings in parallel the results are surprisingly good.  The MPPT will optimise to get the most power out of the sun-facing string, and the other string will contribute but not at its optimum level.  You should get more than 90% of what you would have gotten using 2 MPPTs.

13 hours ago, farmer barnes said:

As I understand it, if I connect the string half east and half west facing, the out-of-sun bank will kill the whole string.

Series production is hampered by the weakest link(s)

If you parallel East-West you'd have the benefit of both with little loss (just don't exceed your inverter's ratings)

I hadn't thought of doing the two sides in parallel. It makes so much sense in my installation.

Thank you very much @PsyWulf and @Calvin