What IS & IS NOT Partial Shading? And how do each affect different Settings?

[bee88man]

Not limited to, but primaraly for Legacy P&O.
What is/are the Theroy(s) so correct settings might be found quicker as opposed to random assumptions and trial and error?

[Vic]

Bee..,

So you are seeing "Partial Shading"  from the Classic?

Out of curiosity,  what Firmware version is this Classic using?

What is the battery voltage,   what are the make/model number of PVs and the number of PVs per string,  and the size of the PV array.

EDIT,  And,  is there ANY Shading of the PV array visible?   Even slight Shading can have a large impact on Solar production  --  this could cause the Shading message/es from the Classic/s.
What is PV input voltage and the battery voltage shown at the time of the Shading messages? <
Thanks,    Vic

[KyleM]

The Alt E store has a great video on shading see below.

https://www.altestore.com/blog/2016/08/wiring-shaded-solar-panels/

Not really going to help you on settings with your charge controller, but it might give you a better understanding on why it kills your power.

Legacy P&O instead of Solar Mode is also a good idea. Many people have had great results with this mode with shading issues.

Kyle

[bee88man]

No Shading Message....just wanting to know better what is considered "shading". And what determinds when best to use Legacy P&O as opposed to Solar  'MODE" settings.

Is it always just partial shading that is the issue?  Are passing clouds considered (partial) shading? Or is it a longer term shading that is issue?

My PV voltages displayed are constantly moving up and down, however, I have no fixed shading items causing any shade here ever, just the sky and whatever the weather is overhead. Is this normal?

48 volt system, 30-SunWorld 245 mono, 5 strings of 3 each into each of the two 200 Classics.
Seeing ~70-85 Volt, depending on ambient outdoor temps.

Biggest question is knowing or having a better understand of the theroy in order to find the best choices for both 'sweep interval timel' and 'depth of watts' settings for Legacy P&O?

Could be others that may find better production with better understanding of theroy/setting choices.

[Vic]

Hi bee..,

Briefly,   Shading is some form of obstruction between the sun and the PVs,   usually fairly close to the PVs.  Personally do not consider clouds as a form of shading ...   they are just clouds.

Even partial shading from a vent,  pipe,  cables,  etc can have a significant negative impact on solar production.

On the systems here,  Legacy P & O  can produce a bit more power than Solar when there are intermittent clouds or thin clouds obscuring the sun.

Would strongly suggest that you use the default parameters for Solar of Legacy,  until you know that you know more than the Classic.   The exception would probably be if you were playing around with other power sources than PVs.

IMO,   just let the Charge Controller be THE Charge Controller,  unless you want that job on a continuing basis ...

EDIR:  OH,   when you said,  "My PV voltages displayed are constantly moving up and down..."  not exactly clear what total variation that you are seeing,   how frequently it is changing,   and what Mode the CC/s are in.

Have seen somewhat more input voltage variation (a few tenths of a volt,  changing several times per second) on the MNGP,  when in Legacy P & O,   than when in Solar Mode<.

Just my opinions,   FWIW,   Vic

[bee88man]

Thanks Vic,

So, it appears there's no sweet spot for custom Legacy P&O settingsto be found aside from never ending adjustments.so just leave it set to defaults.

I'll need to find where default is 'supposed' to be.

[Vic]

Thanks Vic,

So, it appears there's no sweet spot for custom Legacy P&O settingsto be found aside from never ending adjustments.so just leave it set to defaults.

I'll need to find where default is 'supposed' to be.

Hi bee88..,

That is just my opinion.   You could probably find a slightly better spot for the MPPT to operate for that particular moment,  using PVs as the input power source  ...   BUT,   that would change fairly often.

Just seems like trying to track the ideal spot would be very tedious,   and that you would probably loose power production due to always being "behind the curve"  IMO.

You could probably learn quite a lot by playing with settings.   MidNite's boB and the rest of the Engineering crew have been designing MPPT CCs for several decades.   So  believe,  in general the MPPT Tracking/Sweeping is probably fairly effective at producing good power production.

Under certain conditions of very light clouds,  or haziness,   finding a good Max Power Point  seems more difficult,   perhaps you could find a different sweet spot by changing some settings,  but this sweet spot will move around with even small changes in these solar conditions ...

All just personal opinions.   Certainly  doing a Reset to Default values (VMM)  should restore the all values to original.   Using the Local App,  you can save your other personalized settings,   and import them again after doing the VMM.

Customizing settings for other Modes of operation  (Hydro,  Wind,  etc)  can be beneficial,   but  for Solar with PVs,  maybe not so much.

Others will probably have differing opinions.   FWIW,   Vic