Barezzi

Depends on your objective I suppose. If it is to be energy independent then yes. But if it is to save money while beating loadshedding those extra panels push up your LCOE quite a bit, diluting, not enhancing, the economic benefit of the system. I would happily use the grid to charge up the battery if needed - we still have Eskom more than we don't. Heck I could even wire in my 6.5 kVA generator and use that like we did before we had solar.
I should have been clearer ... I meant performance not yield. Chasing production on miserable days is a pipe dream.  So yesterday I got 600W from the roof. Even if I doubled the panels to 12kWp I would only gain another 600W for 5 or 6 hours. So 3kWh more at an additional cost of .... 14 x R3500 = R 49000. While increasing the LCOE of every single Wh ever generated by a whopping 49000/125000 = 39.2%!!!
I could get that same energy by wiring in my generator for what? R3000. And then run it for 30 minutes using around 1 Liter of petrol. Sounds a million times more cost-effective to me. Or just pay Eskom the R5 and be done with it.

Why will it compromise yield on the majority of good solar days? That which does not get used on good solar days does not get generated. Yes, it's potential waste, but far better than watching production anxiously on a rainy day, wondering if you have enough light to charge batteries, and service loads, and whether the wife & kids will be able to have a warm bath tonight or tomorrow morning. It's days like this that can turn one into a nagging power nazi, constantly moaning at family members for making toast and using the microwave. 
I personally started out with 4.56kWp, and it was great, but I soon realised that life would be so much more comfortable with more. The MPPTs also far more efficient at higher voltages. Today my worst power output ever was at around 14H30. For about 10m I barely got 0.22kW out of my North-facing 26 degree 6.08kWp array. that's around 3.6%, and my batteries were at 65%. For me, it has absolutely nothing to do with "bragging rights". One installs what one is comfortable with, both in terms of usage and budget, in order to meet objectives. I am pretty sure that after one or two months you will come to a similar conclusion.
 

Everything except for geyser element (on AC2 out) is on the essential loads AC1 out. Even without scheduling what goes on/off this 10kVA setup seems more than sufficient for the current needs. At this point in the house we have no idea when the grid is available or not 😄 We use kettle, coffee machine, hairdryer, borehole pump, washing machine all at will, on a whim.

Nice setup, but you forgot to install the last row of 4 panels on the right-hand side of your roof
I have nearly as many panels as you have, and in summer my batteries usually recharge before noon.  After that I use the spare energy to boost the water temps in the geyser.  And later in the day the famous Pretoria summer thunderstorms make sure that there's no more generation to be had!
In winter the batteries take a tad much longer to recharge, but at least we are blessed with cloudless weather so it does not really matter...

How is the heat being dissipated?

my 2 cents. If you are looking only at the ROI it makes no sense to spend so much money. If it is your hobby and/or you are concerned about the environment this is a different story and probably the reason most of us here on the site have PV systems. After 2 years of experience with a PV hybrid system and solar geysers (and only looking at the cost benefit) my advice would be to install a PV grid tied system without batteries and 2 solar geysers. 
If the law in your city allows it I would size the PV system to cover on average about 80% of your daily consumption. For load shedding either get a cheap UPS for the very few essential loads you can not live without for 2 hours or invest in a quiet generator. 
The choice of solar geysers depends on your pressure requirement in the hot water system. In my case I needed I a high pressure system. But even a high pressure system will give you an acceptable ROI.  

One of the main reasons for the 15kva inverter. But I dont think mine uses 8kw. I wouldve had a much higher electricity bill I think. I think about half that. 
Thanks for the advice. I really appreciate it, and it does make sense. My problem is however space for all the inverters and that I want to buy the inverter once and just add panels and batteries as I think its easier than adding more and more inverters. 

Very impressive! A very neat and well organised implementation..

Sorry about the title - seems to be a forum rib of sorts ?
Anyway here is my install - was quite challenging doing it all myself with little solar experience. Silly things like just getting inverter on the wall (thing ways a ton) , thank goodness for climbing gear and pulleys, made it a steep learning curve. Hopefully the forum wolves will be kind though   .  
System :Victron Inverter  - Quattro 10000va /  Victron 250/100 SmartSolar MPPT /  20 x 330 Watt Canadian Solar  / Victron BMV702  / Revov 10 kWh / Venus GX running ESS  / ET112 Grid Meter / Home Assistant Integration. In case you wondering system is limited that it can’t feed more than 4.6kW into grid.
Things I would have done differently: 
- Bigger fuse boxes & bit more spacing - 35mm2 wire is difficult to bend
- Wider trucking - same reason as above
My average use is 30-35 kWh per day - system is producing 18kWh on average (mid winter) per day - looking forward to summer. The Battery is on paper too small as most use is in evening, however in Port Elizabeth we can Grid tie one to one and we are on Eskom time of use tariffs, so battery only needs to get me through the 2 peak periods, then use the grid as a cheap battery for balance of time.
With the home automation (Home Assistant) tie-in, I manipulate a few things on system via Modibus to optimise the return:
System makes sure batteries are charged for morning and evening peak using grid if needed  - (buys cheaper power or uses credit generated during day). I do this by changing the Grid set point higher for this period. If there is loadshedding (it reads the loadshedding status form Eskom website) - it changes min SOC from 20% to 50% - that way there is enough capacity in batteries to get through any loadshedding episodes regardless of time of day.  Also notifies me of grid failure over google home and on phone 
Pic 1 - Christmas - trying to figure everything out
 
 
Pic 2 - figuring out cable routes - old inverter/ups in green looking sad
 
 
Pic 3 - Old Main Db Board (nice excuse to tidy up)
 
 
Pic 4 - Honey will we have lights tonight ? - no pressure - all stripped out
 
 
Pic 5 - Main Db Looking bit more tidy - split into 2 - Db1 non critical AC loads - Oven and Geyser on Left ELU -  Db3 - Critical Loads -  balance of house - plugs and lights
(Note Inverter feeds back up to DB1 if grid present so DB1 is on Inverter / solar /battery until there is a grid failure)
 
 
Pic 6 - Revov Batteries 10 KWh- server rack box adapted with some additional home made welded brackets (its a 50kg load) - but nicely off the floor
 
 
Pic 7 - DC Buss-bar -  cramped DC shunt and fuse box  - will know for next time - give yourself more room
 
 
Pic 8 - AC DB 2 - feeds to and from Db 1/D b3 with 3 way change over switch (can bypass inverter if its faulty)  - MPPT on left - Solar DC DB &  fuses on right
 
 
Pic 9 - Solar DB - only partly my work that''s why is so neat   - 4 strings of 5 panels  - bottom 2 cables have subsequently been increased to 10mm2 from 6mm2 shown here - MPPT was kicking errors - seems happier now
 
 
Pic 10 - Overview of installation - Inverter quite noisy (I am noise sensitive) - so nice to be in the garage vs in house
 
 
Pic 11 - Colour GX and BMV installed round corner (more accessible)
 
 
Pic 12  - Panels  - 20 x 330W - 4 strings of 5 - 5 deg - facing NE - raised back 5 because of shading
 
 
Pic 13 - Home Assistant Home Automation Tie in - Note loadshedding sensor (still working on overall layout but its 100% customisable)
 

Pic 14 - Municipal Grid-tie meter with ET112 Grid Meter on right

Who knows these things?
Measurable things are that the Pylontech BMS dropped my battery pack's SoH from 99% to 98% when I hit 320 cycles, so I assume they will drop by another percentage point when I hit 480 cycles?  The BMS gradually keeps lowering their maximum capacity (in available Ah) as they age, so when fully charged ICC now reports that I have 102% of available capacity!  It seems mostly to affect the oldest battery, and I think this is pre-programmed behaviour from its BMS based on cycle count and may not reflect the actual performance of the pack in real life?

I also moved the goalposts by adding additional batteries after starting off with just one at the beginning of last year, and the new ones have fewer cycles on them which affects the performance of the whole battery pack.  We've also optimised our power consumption at night by letting PCs go to standby much sooner, saving a large thermos flask with hot water for instead of boiling cold water each time, dropping the fish tank temperature by a degree or two, heating the house during the day and not at night during winter (we only use the gas fireplace at night), using electric blankets instead of heating the bedroom, etc.
Any way - we are now as close to off-grid as one can get when running in grid-tied mode 😀

Tnx for the compliment,yes the electrician was a very nice guy that came out at last minute and didn't charge an arm and leg to redo the DB.
Will recommend him, he is in PTA East Moreletta Park..
 
Finally my wife thanked me, not only for not having load shedding this morning but also for having her kitchen back, and I am back working in my room as the inlaws are over again... Might have to rip out the floor next.
 
I measured the distance between the fridge and inverter once I moved it back in, 50cm.
Doubt that will give any heat issues, I did put quite some strain on the inverter today, at some stage trying to overload with geyser, pool, washing machine, coffee machine, dishwasher but it never switched off. It did go above 7kva for split seconds but that was it. I will definitely pay attention to the temp in the summer.
All that is left is to tidy the wiring around the combiner box and to label the DB.
I am very happy with my setup and looking forward to optimize usage.
I did measure quite a bit of voltage drop, around 16V. I am using 6mm wire from the panel to the combiner (15-20m) and 16mm from combiner to inverter (7m), little bit off heat on the fuses but the cables were cool. PV wattage peaked at around 3300W, I might be able to add another panel to each string but definitely not now.
Last night the battery discharged to 50% around 12am, then recharged using eskom and discharged again to 50% at 7 this morning then started charging by the solar around 7am
The monitoring software is still a bit of a nuisance for not being instant, but it will do. (I did receive a Monitor software on a CD, still have to check that out)
Here are some screenshots of the mobile app and cloud server.
If anyone is not yet convinced to get solar or a Growatt inverter...I am certainly glad I did it. used 15kWh from solar today and no eskom...
Cheerio, thanks for reading.
 
 
 

Ohh man.....Getting old is not for sissies. I have been running local emoncms on Ubuntu for the past 2 years with no problems and through a couple of Ubuntu version upgrades. Then bang...the last upgrade from Ubuntu from 19.04 to 19.10 seems to have had Mysql as well as PHP changes. Needless to say my emoncms would not work anymore and after spending 2 days trying to kick-start it, I had pretty much given up, formatted and reloaded Ubuntu Mate 18.04. Loading the new emoncms on Mate went well, but do you think I could remember all the formula's I used in the Inputs process (tweaked over 2 years)....No way.
Today I have it finally set it up to where I want it. And the biggest moral to today's story is Backup, backup and don't forget to backup.

Hello @patalhetas this was done ages ago so Some of it went missing but here is some of the Images that I still have and can be available here. 
You could edit them with something like GIMP or Photoshop (if you have a copy) 
Hope this helps!

I have finally finished installing my Victron system , started by rewiring my old DB , wired from DB to Multiplus with 4mm .Then installed Solar MD 7.4kwh lithium and commissioned with the help of Kalo Yan from solar MD. With all that running smoothly I moved onto the 350w Art solar panels . I decided to go with 10 panels connected in 5 strings fed into fuses then Noarc 63A. I lazer cut my own roof mount brackets from 4.5mm stainless steel and used unistrut for the beams as I wanted a flush look if possible. I plan on running an ESS setup.
 

I see the system working like an old school turbo charged car with lots of turbo lag.
Even if your inverter can do something like a 5 000w constant draw with a 10 000w spike, it would trip before it can even deliver that if your battery bank is sized too low.
The inverter need to supply the power you are asking from somewhere, it want to get it from the PV, but the PV’s and inverter has lag (turbo lag if you will), so first it will get it from the batteries, if the batteries can’t supply it, “CLICK”, self induced load shedding, reset everything, let’s try again.... rinse repeat.

An update from my solar Lab:
As some of you might remember, I'm currently running 3x InfiniSolar 5K combined into a single-phase AC source of 15kW. Most of the year, it's okay, since there's plenty of sunlight and the idle consumption of the three running inverters does not matter. But during winter, it's a completely different story and every watthour, that I'm able to save, is crucial. Therefore, I decided to code a feature that will allow me to run just a single inverter 24x7 and once there's need for a more power, start two other inverters automatically. So, here's the result:
I created a short LUA script in Fibaro, that's constantly checking the AC load. Normally, just one 5kW inverter is running. Once the AC load goes above 4000W, the script starts other 2 inverters. It takes just a couple of seconds, and 15kW of power is ready to serve the loads. I've added a safety function, that will turn-off all three inverters once the SOC of the Pylontech stack falls bellow 25%. Once this happens, there's an ATS that will automatically switch all the house circuits to "ESKOM". Later, if all the inverters are OFF and SOC goes above 70%, then the script starts 1st InfiniSolar and the ATS will switch all the circuits back to the PV. Here's the GUI:
  
Here's the main part of the LUA script:

Since I have an EV charging wallbox installed too, I've also added a second script, that works like this:
Normally, just one 5kW inverter is running. If there's no EV connected, the wallbox advertises 10A AC charging (2300W). Once the EV starts to draw power from the wallbox, the script will start another two inverters. Once all three inverters are running, the script will instruct wallbox to advertise 32A charging (7300W). GUI:

I was too lazy to implement a function that will automatically turn-off two of the inverters once their power is not needed. But since I can turn them off via the mobile app, I'm okay with that. But I will add such power-off function later....maybe
 

How to charge your Pylontech US3000 and why
From time to time, there's a discussion on Pylontech US2000/US3000 batteries and what is the best charging voltage for them. So, here's the answer based on my personal experience:
C.C. = 52.5V
C.V. = 52.0V
 
Why:
First of all, it's important to clarify what the term "charging voltage", sometimes referred as C.C. aka constant current, means. It's NOT the voltage that's being created by the charger and then applied to the battery terminals. In reality, the charger just pushes current into the battery, while constinuously measuring the voltage on the terminals. Once the voltage reading on the terminals is equal to the value that's set as charging voltage, the charger stops pushing current. Then, based on the selected charging profile, the charger goes in the next stage, like C.V. aka constant voltage, for example.
If the C.C. voltage is set too high, the charger will continue to push the current in the batteries for too long. The voltage will rise above the safe level for that given battery chemistry and the cells will overcharge, swell and take damage.
In order to protect the cells, US3000 has a balancer for each individual cell and a MOSFET for each brick. Once the voltage of the individual cell goes above 3.480V, the balancer will kick-in and start to burn the excessive current, turning the electric energy into heat. That's the way how US3000 ensures that at the end of charging all the cells have equal voltage, in other words "are balanced". Of course, cell balancers are not powerfull enough to burn all the energy that might be potentially pushed by the charger. That's the reason why there's a MOSFET in the battery pack. If all the balancers are already burning energy and the charger is still pushing energy, then the MOSFET will limit the current in order to protect the pack.
 
In the specsheet, Pylontech recommend to set the charging voltage somewhere between the 52.5V to 53.5V:
 

There's 15 LFP cells in each US3000 pack and balancers are starting at voltage 3.480V per cell: 15 x 3.480V = 52.2V
So, the setting C.C. to 52.5V (52.2V + 0.3V) ensures that all the balancers will operate correctly and at the same time, they won't be overloaded.
If your solar charger is actively communicating with the US3000 via CAN bus or RS485, then he can read the battery voltage via this digital communication. Therefore, it does not matter how long the battery-to-charger cables are and whether the charger itself is measuring accurate or not. The voltage is measured by the BMS and communicated digitally. In that case, the best is to set C.C. to 52.5V.
If your solar charger does NOT utilize BMS comunication, then he has to rely on his own voltage measurements. In that case, one has to take into account the length of the battery-to-charger cables, all the joints resistance and the associated voltage drop. Therefore, it might be necessary to adjust C.C. to a higher value, like 52.6V or 52.7V for example. There's nothing you can break if you will experiment and raise the C.C. slowly in order to find the best value for your setup. Just be sure to stay away from the maximum allowed voltage as described in the specsheet.
While the specsheet allows charging voltage up to 53.5V, it's not a good idea:
The higher voltage puts a higher load the balancers, mosfet and on the cells too. All the excessive energy is wasted and turned into heat. And the heat is generally not good for the cells, of course. Second reason, why setting the C.C. to the maximum is not a good choice is the fact, that during the charging there might be occasional spikes of power that will go to the battery. Sometimes these spikes are caused by the charger algorithm itself, sometimes they are caused by a changing light conditions or by turning ON/OFF bigger loads. Once this happens during the charging, and the battery is already at it's 53.5V maximum, the BMS will sense the overvoltage and throws an error. If not corrected immediatelly, it will shutdown the battery.
 
How to set C.V. voltage:
The LFP cells used in US3000 have a resting voltage 3.2V per cell. Technically, there's no "float" voltage that you need to apply to LFP, like is common in the Lead-Acid world. LFP cells are best to be charged and then disconnected. This is based on the fact that you can overcharge and damage a LFP cell even with 100mA of current, if applied for a long time.
On the other hand, in solar applications it's impossible to disconnect the batteries from inverter once fully charged, since the batteries are acting as an energy buffer 24x7. Therefore, it's good to set C.V. to a value that will supply just a tiny amount of current into the batteries in order to keep them topped, and live with the fact that balancers will kick-in from time to time and will waste some energy by turning it into heat. With some other types of batteries, where balancers are visible, you can see this state - LED on each balancer blinks randomly, once per second or two. It's like a heartbeat. For a shame, Pylons don't have this direct visibility and you have to go into CLI, if you want to see what's going on inside the battery.
Based on that, I'm personally using C.V. = 52V,  so the balancers are not wasting excessive amounts of energy, and operate only when really needed.
 
US3000 battery:
 

Phantom BMS sitting inside a Pylontech battery:

 
CLI info for a stack of 8xUS3000:
pylon_debug>pwrsys Power System Information --------------------------------- System is discharging Total Num : 8 Present Num : 8 Sleep Num : 0 System Volt : 49756 mV System Curr : -17724 mA System RC : 558692 mAH System FCC : 588892 mAH System SOC : 94 % System SOH : 100 % Highest voltage : 3319 mV Average voltage : 3317 mV Lowest voltage : 3315 mV Highest temperature : 22000 mC Average temperature : 21500 mC Lowest temperature : 20000 mC Recommend chg voltage : 53250 mV Recommend dsg voltage : 47000 mV Recommend chg current : 118400 mA Recommend dsg current : -296000 mA Command completed successfully Note one interesting information:
The stack has 592Ah of nominal capacity, but the recommended charging current, advertised by the BMS, is 118A = C/5.
Recommended discharging current, advertised by the BMS, is 296A = C/2.
No matter what values (much bigger) are being promoted in the specsheet, I would say that the battery designer had a very good reason why he hardcoded C/5 and C/2 into the BMS as recommended Amps.
 
CLI info on the 1st brick:
pylon_debug>info Device address : 1 Manufacturer : Pylon Device name : US3000A Board version : PHANTOMSAV10R03 Main Soft version : B65.6 Soft version : V1.3 Boot version : V1.4 Comm version : V2.0 Release Date : 18-09-12 Barcode : PPTAH02 Specification : 48V/74AH Cell Number : 15 Max Dischg Curr : -100000mA Max Charge Curr : 102000mA EPONPort rate : 1200 Console Port rate : 115200 Command completed successfully  
State of Health for 15 cells in the 1st brick:
pylon_debug>soh Power 1 Battery Voltage SOHCount SOHStatus 0 3317 0 Normal 1 3317 0 Normal 2 3318 0 Normal 3 3317 0 Normal 4 3317 0 Normal 5 3318 0 Normal 6 3318 0 Normal 7 3319 0 Normal 8 3316 0 Normal 9 3316 0 Normal 10 3317 0 Normal 11 3318 0 Normal 12 3319 0 Normal 13 3317 0 Normal 14 3318 0 Normal Command completed successfully  
Statistics for the oldest brick in a stack of 8:
pylon_debug>stat 8 Device address 8 Data Items : 0 HisData Items : 2048 MiscData Items : 122 Charge Cnt. : 0 Discharge Cnt. : 3180 Charge Times : 31004 Status Cnt. : 3179 Idle Times : 41151 COC Times : 0 DOC Times : 0 COCA Times : 0 DOCA Times : 0 SC Times : 0 Bat OV Times : 0 Bat HV Times : 0 Bat LV Times : 0 Bat UV Times : 0 Bat SLP Times : 0 Pwr OV Times : 0 Pwr HV Times : 0 Pwr LV Times : 0 Pwr UV Times : 0 Pwr SLP Times : 0 COT Times : 0 CUT Times : 0 DOT Times : 0 DUT Times : 0 CHT Times : 0 CLT Times : 0 DHT Times : 0 DLT Times : 0 Shut Times : 1 Reset Times : 14 RV Times : 0 Input OV Times : 0 SOH Times : 0 BMICERR Times : 0 CYCLE Times : 62 Pwr Percent : 95 Pwr Coulomb : 254001600 Dsg Cap : 4614627 [email protected] Cnt : 0 [email protected] Cnt : 0 HT Cnt : 0 LT Cnt : 0 LV Cnt : 0 LifeWarn Times : 0 LifeAlarm Times : 0 Command completed successfully Note the Cycle Times, this brick has 62 full cycles on it's meter. One full cycle is accounted whenever you discharge a full nominal capacity from the pack.
 
Hope the above info will help someone to understand how to treat these batteries.
Youda
 
 

Although I'm using Pylontech personally, there were two major objections that I had:
Thin cables was the first. My second objection was 15S arrangement of the cells. Speaking of amps, it's not just about cables. There are two internal passthroughs in each Pylon brick and SurLok 5.7mm version also has it's limitation (120 Amps). Manufacturer clearly state, that if you want to pull more than 120A from your bank, then you should either split it into more smaller piles or connect it using 4 cables instead of 2. Personally, I don't like the 4 cables option, as it might create a slight imbalance when charging/discharging. So in my case I split the pile into the two smaller ones, 5+4 bricks.
In theory, Pylontech could use SurLok 10.3mm version on the product, which is rated up to 350A and ready to be crimped on a 95mm2 cable. But I perfectly uderstand why they went with the cheaper version:
Choice of 25mm2 cables generates nice savings on the lugs and on the copper. With the 8 bricks combined in a single pile, there's around 32 individual connections and the transitional resistance starts to build-up. Therefore, it does not make a sense to pull the theoretical maximum of 592A (8xUS3000) thru all these "resistors". No matter how thick is the cable, every unnecessary flexible connection is a bad thing. Given that the majority of residential installations are having just around 4 bricks, 120A should be okay for most of the customers. Like I said, I still think that Pylontech should use the bigger lugs and thicker cables, but I understand why they decided to go the cheaper way.

The AC-DC charger idea looks like this:

The charger can be an industrial 48V DC charger, or it can be InfiniSolar Plus 10kW 3-phase, like depicted.
If that's the case, it will give me some additional MPPT inputs too
Speaking of automation of charging from the grid, I'm talking to all my Inverters and Pylontech batteries via the PLC, so it's quite easy for me to turn on/off the charger, read SOC or any other operational value:

 
 


 

Finally - the 3rd Inverter arrived a couple of days ago, together with the two more US3000 bricks:


When adding the batteries into my rack, I tested whether its possible to have more than 8 US3000 bricks in a single BMS group. In the US3000 user guide, there's a limit of 8 bricks per group noted, but I saw that some eshops were listing US3000 as capable of grouping up to 12 bricks. Long story short - I verified that max number in a single BMS group is really 8. When all nine bricks were daisy-chained, the ninth brick was skipped during the startup self-test. So I divided the batteries in two groups, which works fine, of course.

Note: the left rack is empty. These babies are quite heavy and sice the rack is more than 2m tall, it's not a pleasure to raise the brick over the one's head while trying to fit it between the narrow vertical rails.

 
New inverter was "bolted" on the wall and all the communication and current sharing cables rewired. It's a parallel setup with 15kVA combined in a single phase. It's really interesting that despite of the fact that I have AC, DC and data stuffed in a single trunking, it still works! I would say that all the noise and powerspikes would hinder the communication or even kill some sensitive equipment. But, so far so good and I've seen couple of storms here too. Let's see for how long will this setup survive 🤨


 

Hi guys a short update...
A couple of weeks ago, I've added a second LiFePo4 battery pack to my Solar LAB. So, it's 20kWh of lithium now.
Before:

After:

Also, I was not really satisfied with the reliability of my wireless monitoring. Originally, I used Z-Uno boards to read-out the RS-232 serial data from the inverters and send them over the wireless Z-Wave protocol. It worked, but sometimes half of the monitored values got stuck, while the other half was okay, etc. Therefore, this time I went for a small DIN-rail mounted PLC (Tecomat Foxtrot). Did a bit of coding and now I'm transferring the data over the ethernet, with the help of RestAPI and JSON. It's much faster and rock-solid
Since this PLC has a built-in display with UP/DOWN buttons underneath it, I used it for debuging and for displaying the operational state of both InfiniSolars too.
Current layout of the distribution board:

 
Detail of the PLC display, Screen 1 of 6:

 
Since I had to code anyway, I did a small improvement in my home-automation logic and now I'm able to switch ON/OFF each inverter directly from the phone.
Detail of the first inverter in the mobile app, note the ON/OFF buttons that I've added:
   
 
Now, I'm thinking of adding some more logic, that will enable me to automatically cascade both inverters:
- For the AC loads under 3kW, only one 5kW inverter will be active, while the other will be in the low-consumption charger-mode.
- Once the AC loads will go above 3kW, the logic will turn-on the second inverter too.
- Once the load will drop under 2kW for ten minutes, the second inverter will be switched back to the charger-mode
Shame is, that I'm feeling toooo lazyyyy now.....

A small partial solar system is great for a Solar DIY enthusiast. He will know what its for and what the system was designed for, but offering it to a client is a completely different ballgame and it hardly ever end good. It normally goes as follows.
Customer want a system to keep the (Inside) lights on , have one fan thats running through the night and want to watch TV till 10, so after a lot of discussion everybody will agree and install - Load-shedding sorted. At the time of the installation all the lights on the dedicated circuit were LED's, but a month later you get a call, "The Batteries must be faulty, they go flat much quicker than before " - investigate and 2 globes pack up and were replaced with 2 old 100 watt incandescent that was still in the cupboard.... Then another few months past and now outside lights must be added for security purposes, just come have a look, we only have LED spotlights outside, it cant be difficult. (The one client had a total of 680Watt of LED spotlights.  Then a feeder in the substation blows up as Eskom restores the power and the 4 hour load-shed turns into a 16 Hour power outage - Next Call. If we add a extra plug or run and extension, we can mos sommer plug the Fridge in as well, we have after all spend all this money so far and for that amount the system can run a fridge as well........... NOT SO?? And the next call and the next and then the Aircon........................ And before you know it, because you wanted to help the client save some money, he is running around telling everybody, Solar is @%#$, you cant even run your fridge or outside lights, and you spend months doing damage control. 
Believe me, For a DIY project, please go ahead, but offering something like that to a client again, without a serious contract, never ever again..........

Thanks for all the comments!
Here's a graph plotting inverter load, battery & grid power during the same time.
The spike in the middle (12:30 - 13:10) was a 2kW hot water element turning on (via Geyserwise timer) to give our evening bath water a temperature boost.  Smaller spikes due fridge/freezer motors, and base load mostly swimming pool pump and a few computers.
I am not allowing AC charging, only PV.  The time and current based charge is set for <1 A for 60 minutes and <48.6 V, so it should not interfere.  I'll see what it does today with CC = CV, as reference, then try again with CC > CV tomorrow to see if I can reproduce the weird behaviour.
se dangerous "iron" PS:
PS: I notice a lot of comments about "ironing".  I presume that it refers to the dangerous action of applying extreme heat to non-wrinkling fabric for the purpose of prematurely aging the fibers so that you have an excuse to buy new clothes?  I'm glad to report that we do not own any of those evil devices and would never consider taking part in such unnatural rituals :-)

Please be careful not to fall in this trap while designing your system. The following pictures will show you why. The aim is to have everything green. Yellow means that the output is been limited and adding more strings will hold  absolutely no benefit for you. Although you add more to the input, the Mppt wont allow out more than its output rating, in this case its 100 Amps. (No benefit except for early morning, late afternoon and cloudy days, but in the middle of a perfect sunny day, your array will be in idling mode) 
At the bottom of the data sheet, point  1A, you will see the logic's behind it. 

Now look at an example using panel supplied by the app itself. 
Start with one string of 4. All green (Total PV = 1320 Watt)  (Total PV = 2640 watt) Add 1 string. Cold whether output gets clipped, note we are getting closer to Nominal  PV power on a 24Volt system as per Datasheet 2 posts up (2900). (Total PV = 3960 watt )Adding one string more.  Now Cold and hot weather output gets clipped. Everything you add after this point will not contribute to the output under normal sunny conditions and will only come into play during low light or cloudy conditions.  (Total PV = 9240 watt ) I can add another 4 strings, without adding 1 amp to the output and still have an "Accepted" Green at the bottom.  (Total PV = 10560) Only when I add string number 8, the app tells me "NOT accepted" Although the app allowed me to add 4 more strings I had absolutely no benefit on the output side, that is why it is best to design your system toe the Nominal PV Power for your system voltage on the Data sheet, and if you have some extra money, add 30% to that, to help in low light conditions. Anything more than that will be a total waste of money for most parts of the year. 

 

I believe together we all can save the planet or at least SA.
- Off topic -
When the water crisis hit Cape Town and you couldn't get an borehole installer to even answer your call, I dug my own borehole 9m deep with an auger that I made myself.
We are still using it to this day and use less than 800 liters municipal water a month.
Me, myself and I, can get 3000 liters a day out but only using 500 liters a day.
9000 liters of cleaned, filtered, drinkable water in storage.