Noobie

As others have more or less pointed out, it's because the shaded panel is weak and drags the string voltage down as the MPPT draws more current. That's the local maxima mentioned. That situation will remain unless and until the MPPT drags the whole string voltage down a fair bit further, by attempting to draw more and more current, and it does so far enough that the shaded panels go down to zero volts (technically slightly negative). At that point, they go from weak panels to strong diodes, so as the MPPT attempts to draw more current, the shaded panels no longer sag lower in voltage, and the overall power goes up. That's the true maximum power point.
In practice, with say a toilet pipe or TV antenna shading multiple panels, there could me multiple peaks of different power levels, and the one that has the true maximum power point could change with time. Hence, a full scan every few minutes is best.
As far as I know, Axperts don't do proper MPPT scanning, and will only find the "false" maximum. @Georg594 has patched one Axpert firmware for better shade performance, but my understanding is that each patch has to be tuned for a particular number of panels. It would be best to fix the algorithm to perform true MPPT tracking, but that's pretty complex.

Actually the MPPT will follow the reducing current capability of the shaded panel towards lower current and higher voltage - this is the local maximum (and also the true maximum until shading gets too bad).  To break out of this, it needs to draw more current again.

Yeah. MPPT algorithm is a very important factor, but very few manufacturers specify what theirs is, so it is very difficult to know how well they will handle shading.
BUT, I just realised that this can not explain your problem.  The voltage should go UP for the false local maximum:

These are 2 of my strings, as the chimney shade moves over one of them. You can see how initially the current drops and the voltage goes up - this is the tracker following the false maximum. But then the current goes back up until it is almost the same as pv2 again, and the voltage drops - this is the tracker jumping back to the true maximum power point.
I can't think of anything that would cause both voltage and current to drop...

Eish.  These things are always tricky.
Firstly, each solar panel is actually an array of a number of parallel strings.  Most solar panels have limited (if any) internal bypass/blocking diodes, so shading even a small portion of a panel can potentially limit the entire output of the panel (depending on how many internal strings are affected by the shade).
Then you have the series string with one affected panel...  There should be an optimum power point where all the remaining panels are producing their normal current, at their normal voltage, but the one affected panel is bypassed (total panel voltage will be the forward voltage of the bypass diode).

(Shamelessly stolen from https://blog.spiritenergy.co.uk/contractor/solar-panel-shading-analysis )
Now MPPT stands for Maximum Power Point Tracker - and that is exactly what many do - they track the maximum power point. So as the one panel is shaded, they follow that one peak (labelled 'Local max') down, following the maximum power that the shaded panel can produce. But the MPPT never discovers that there is another, much better, power point that has formed at a higher current and lower voltage.
There are some MPPTs that have very good shading support, and will occasionally sample other possible maxima - but most will just track that one bogus power point.

https://www.electronics-tutorials.ws/diode/bypass-diodes.html

hi there,
i had the same issue when i installed my solar panels,  but it was quickly resolved in the Victron MP2 settings. My installer/ programmer sorted it out.
Speak to your programmer to fix the settings.

Thanks for the inverter. Working fine after the initial battle with EPM. 

The Load Shedder is a smart power detector that turns off appliances, geysers and pool pump’s when load shedding starts.
Extending battery uptime by reducing the load on your battery. The load shedder consists of a Sonoff mini unit that gets powered by your inverter and the relay monitors Eskom power. It automatically runs automation triggers with your preset choices.
What’s in the Box
1x Genuine product box
1x Sonoff Device
1x Monitoring Device
1x Din Base Holder
1x Loadshedder Pilot Light
2x Communication cable identifiers blue
1x Wiring Diagram with instructions.
1x Full support for installers only.
Features
Extending battery time during load shedding Reducing battery load automatically during LoadShedding Extending battery lifetime by reducing battery cycles Reducing power consumption and demand automatically based on your requirement Automatic load recovery when power is restored with delays Simple scene trigger for LoadShedding Day time and Night time configurations  
Benefits
Less outages due to inverter flat batteries. Saving money on battery replacement due to reducing cycles with lower loads. Load management and monitoring. Simple integration into other smart home platforms. Integration into most big brand aircon like Samsung and LG via Broadlink and IFTTT. Google and Alexa compatible. The final piece of the smart home system that monitors Eskom power feed and manages your inverter load all in eWelink. Simple yet so effective that the kids can’t even run your batteries flat with the microwave or kettle. Even the hairdryer won’t be able to draw power during load shedding unless you so chose. This unit has been field tested for over a year now across multiple site’s and we are very pleased with its success and reliability. Assembled and installed correctly the Loadshedder compliments any inverter system.
It will automatically shut down pool pumps, geysers, dishwashers and any home automation devices that you deem non-critical in order to preserve battery power.
No additional re-wiring of DB board is required. All appliances that need to be controlled require smart devices like Sonoff Basic or any other Sonoff products.
Full integration into other smart home platforms like Smart Life, Samsung Smart Things and Top 20 brands. This is fully cross-platform designed.

Entry link as below. Thanks All.
https://app.viralsweep.com/sweeps/full/9e8ee5-124835?framed=1
Sincerely
Jason

That Load shedder Is the best and biggest game changer ever!! Kid you not I learnt about it 2 weeks ago... Installed 3 units already. One controls 5 socket adaptors I made to switch fridges off...
When I get a gap I will explain how works
Saves me running circuits when we install inverters...
basically a wireless cable haha.

The reason people just replace PCBs and don't do component level repair is that it is often more cost effective to do so. You can spend a lot of time trying to do a repair and not be guaranteed of the outcome, so often PCB-level repairs only make sense when the alternative is very expensive or unavailable.

@BritishRacingGreenhis your man ... Hard to find qualified ppl these days & ppl that love what they do. What more can I say. His currently fixing water damaged OG7.2s. 3 dead machines arrived in his workshop & 2 are working already. 

Sorry for jumping in. I know this place called power forum store. It's a pretty reliable place 😉

BN_Impi-settings_201303 2019 04 01.pdf
These are the settings I got from Blue Nova in 2019, they may be out of date but worth a shot!

@mzezman have a look at the cement tile that isn't in line with the rest of your roof tiles, looks like it wasn't put back into place correctly or slipped,this could cause a roof leak.

If you put a 30amp circuit breaker inside the DB on the 4mm cable feeding the inverter and a 30amp circuit breaker on the 4mm cable coming back from the inverter into the DB that will be to code. Provided that your inverter doesnt draw more than 30amps you will be ok. As it stands the 4mm cable supplying the inverter is connected before your homes main switch meaning that you are not able to switch it off via the mains (very dodgy) The 30amp circuit breaker feeding the inverter should be connected after the 60amp mains isolator switch.
I'd suggest you have an electrician have a look at the other shortcuts they took as this is very concerning.

If you put a 30amp circuit breaker inside the DB on the 4mm cable feeding the inverter and a 30amp circuit breaker on the 4mm cable coming back from the inverter into the DB that will be to code. Provided that your inverter doesnt draw more than 30amps you will be ok. As it stands the 4mm cable supplying the inverter is connected before your homes main switch meaning that you are not able to switch it off via the mains (very dodgy) The 30amp circuit breaker feeding the inverter should be connected after the 60amp mains isolator switch.
I'd suggest you have an electrician have a look at the other shortcuts they took as this is very concerning.

If you put a 30amp circuit breaker inside the DB on the 4mm cable feeding the inverter and a 30amp circuit breaker on the 4mm cable coming back from the inverter into the DB that will be to code. Provided that your inverter doesnt draw more than 30amps you will be ok. As it stands the 4mm cable supplying the inverter is connected before your homes main switch meaning that you are not able to switch it off via the mains (very dodgy) The 30amp circuit breaker feeding the inverter should be connected after the 60amp mains isolator switch.
I'd suggest you have an electrician have a look at the other shortcuts they took as this is very concerning.

If you put a 30amp circuit breaker inside the DB on the 4mm cable feeding the inverter and a 30amp circuit breaker on the 4mm cable coming back from the inverter into the DB that will be to code. Provided that your inverter doesnt draw more than 30amps you will be ok. As it stands the 4mm cable supplying the inverter is connected before your homes main switch meaning that you are not able to switch it off via the mains (very dodgy) The 30amp circuit breaker feeding the inverter should be connected after the 60amp mains isolator switch.
I'd suggest you have an electrician have a look at the other shortcuts they took as this is very concerning.

Otherwise some guys are doing it with a small camera and a microprocessor
https://github.com/nohn/watermeter 

Some volumetric water meters have a magnetic pulse that allows for the flow to be read. 
Need to check if your meter has a point to put the sensor on.
https://assuredautomation.com/pulse-output-water-meters/
Uou can then use ESPHome with a NodeMCU to count the pulses for you.
https://esphome.io/components/sensor/pulse_meter.html?highlight=meter
 
 

Takealot has this one. Found it a while back. you can also check out their website but they only sell via Takealot or maybe their own site.
 
https://www.takealot.com/gaugeit-hourly-ultrasonic-smart-water-measuring-and-monitoring-d/PLID70582043

also this one maybe interesting but wont do a shutoff. Which one could manually do via a Sonoff? and a water shutoff solenoid?
 
https://www.nanoview.co.za/

This is the closest I could find: https://www.kamstrup.com/en-en/water-solutions/smart-water-meters/multical-21
I'm sure something better must exist - this one does not connect directly to anything that I have, so additional hardware would be required.

On the side of my house I have this old meter - no longer used, and the wiring you see.
My power comes through here since throwing that breaker turns off everything.
The red sign says "Earthed to neutral" or "aan Neutraal geaard"
i do have an earth rod down below which I assume is connected somewhere here too,
The breaker is 80A. Not sure what’s in the box bottom right that is labelled 25A.
The R10 fine is a scary thought!
Can anyone tell me how this works and what goes where?
Is this TNC-S?