viceroy

If you are planning to use 6mm² Surfix twin and earth in trunking or conduit i would use 32A breaker as the 7kw single phase charger will draw continuous current of 30.4A.
●7kW @ 230V ≈ 31A continuous load
●Use a dedicated 32A breaker
●6mm² cable over 5m is perfectly adequate
●Dedicated 30mA RCD (Type B minimum) required (unless otherwise specified by the charger manual)
●Local isolator in the garage
Industrial plug can work if properly rated 32A, but best practice for EV chargers is hard-wired rather than plug-and-socket, since it’s a high continuous load and a fixed installation.

All circuits must originate from and be protected within the "MAIN" distribution board that complies with SANS 10142-1.
The EV charger circuit requires its own dedicated circuit breaker and appropriate earth leakage protection (Type B), which must be installed in the "MAIN" distribution board. The main or first distribution board must have a main switch disconnector that can cut off the entire supply, and this switch should be mounted in or next to the DB.
The "point of control" is defined as the point at which the consumer has access to a device (the main switch) to switch off all electrical installation from the electricity supplied by the point of supply. 
You are not allowed to connect any curcuit before the main switch in the main or first db board( supply cable point of control). The budgie box against the wall is mainly for isolation purposes should an electrician need to change the main switch.

If you install a sub-DB in the garage fed from the main DB after the main isolator, the installation is fully compliant. The key requirement is that the feeder cable to the sub-DB must be correctly sized to supply the combined maximum demand of both the inverter and the EV charger. A 10 mm² copper feed from the main DB (taken after the main switch) is generally adequate for this application, provided that: The cable is correctly protected by an MCB sized for the cable’s current-carrying capacity. The sub-DB contains the appropriate switchgear, including separate protection for the inverter and the EV charger. Voltage drop is within acceptable limits for the run length.

@viceroy ,
Maybe Municipal Permit = an updated COC, as you are modifying the electrical installation of your house.
And while you at it, better double up on your complete Solar installation, you are going to need it!

Unfortunately can't give advice on either ... I installed my wallbox without municipal permit - never even heard that this is required, surely that's just for a commercial install?

From a safety perspective it should be fine to feed directly from municipal supply (after the municipal breaker and meter), but not sure what the by-laws say... following...

Got a cable custom made for me by a local PC guys.
Used Billy's cable layout from the mentioned thread and instant BMS recognition.
Inverter 2 -> Pylontech 6
Inverter 4 -> Pylontech 4
Inverter 5 -> Pylontech 5

Thanks, I did read that already, and it was useful, but I'd rather buy a correct cable than be hacking at cables or having to go out and purchase RJ45 crimping kits.

Have fitted 12 Kodak OG 7.2 inverters.   All 100% successful and reliable
I like the fact that you can operate it during the day as Solar output first during the day and Utility at night 

I'm interested in what field you're studying?
And also, done.

I'm interested in what field you're studying?
And also, done.

I've blown at least three 16A fuses on my PV side, even though the max current according to the spec sheets isn't much more than 10A...
I assume that fuses simply age and fail after some years.

Circuit Breakers can typically either have a thermal / magnetic or an electronic trip unit fitted. Some points to consider are:
1) Electronic trip units are far less affected by ambient temperature.
2) Thermal magnetic trip units typically have to be derated for ambient temperatures above 40 degrees C. (Eg. at 50 degrees, delta T = 10 degrees, 5% current derating)
3) Trip units are sometimes interchangeable for AC and DC circuit breakers. As @plonkster pointed out the thermal protection of the trip curves are identical since the bimetal strips are responding  to the RMS value. The instantaneous protection against short circuits are influenced by the "ferromagnetic phenomena" which in tun is affected by the circuit breaker design and the way the poles are connected. ABB have a coefficient called "KM" that the instantatneous trip value for AC has to be multiplied with to obtain the DC values. This coefficient varies between 0.9 - 1.3 
So coming back to @viceroyproblematic circuit breaker.
1) I would suspect that the breaker may have a high internal contact resistance which is causing  localised heating near the bimetal strip.   
2) Other factors such as undersized cabling (@Chris Louw), poor crimp connections, incorrectly tightened etc. will also cause localised heating resulting in a derating of the trip setting.  

Thanks all.
Looking back through the history, it's tripped 4 times, 42A, 49A, 26A, and yesterday at 27A. Not a great record for one month. Definitely looking like it's faulty.
Breaker is warm to the touch when I've been there to catch it.
Going to play it safe and replace the breaker, and the wiring for that section.

It's either 12V * 210Ah or 24V * 105Ah, depending on whether the batteries are connected in series or parallel.
Regardless though of how they are connected, they still contain the same Wh, ie. 2520.
 
Question 2.
You would add another string of 2 batteries that are identical to what you have now. The new batteries would be connected in parallel to your current string (which are connected to each other in series btw).
Question 3.
With a 5kva inverter, you would be able to supply 5kW of power to devices, ie. 2x 2.5kW kettles, or 5x 1000W microwave ovens.
Your batteries determine how long you can power the load for. Having 8x 105Ah batteries would give you a total capacity of 210Ah @ 48V (2 parallel strings of 4 batteries (connected in series)) which is 10080Wh total. You shouldn't really be drawing more than 50% of that if you want the batteries to last, so 5040Wh. With 5040Wh, you can power 5kW of devices (remember the 2x kettles, or 5x microwaves) for 1 hour, or you could power 1x microwave for 5 hours, or you could power something using 350W for nearly 14.5 hours.
Not answering the other questions as they have been answered already.

@desiji, @ChristoSnake What is your daily DOD?
I'm trying to keep mine above 40% daily in the hopes that this massively extends the cycle life of the batteries.

Yup, the ripple switch has 4 terminals. Two powers the device itself, and the other two switches the power to the geyser. They are not fed via the same breaker. The idea is that I can turn the geyser off at the breaker, but the ripple switch remains on and can receive signals from the grid.
If you don't do it this way, and the ripple is sent while you have things turned off, you will miss the signal, the wife will have a cold shower, and your life will suck.
In my house the ripple switch was wired wrong. Did not have a separate supply line. Then came the solar geyser in 2011, and shortly after a timer, and around that time I bypassed the ripple switch as it caused too much trouble.
 

Still a bunch to do/redo, but a slight miscommunication on Friday afternoon kinda forced me to get my ass into gear.
Got home from fetching the kids from school and found out we had no power. This was a surprise as there was no load shedding scheduled, but through January there have been numerous substation trips, so I figured it was that. In a frantic panic to get the house, or part of the house powered before the wife got home (she's been on my case about finishing this project), I began feeding wires through the wall, connecting things up to the second DB and inverter, and trying to finish up before it got dark.
Needless to say the cause of our outage was a lack of credits in the pre-paid meter.🙈
The end result was an almost working system. In my rush, I'd done something wrong and turning the downstairs lights would trip the EL. Turning on the main geyser would trip the sub-main db board EL. It was dark, I was annoyed, so the lights and the geyser stayed off that night.
Saturday morning, I got up early determined to sort out whatever I'd messed up. I was pretty sure it was Neutral related, but wasn't quite sure what yet. I had two suspicions though. Either one of the circuits was bonded to the wrong neutral bus (Each DB has a separate neutral from the other) or how I was connecting neutral in the main db to the inverter was wrong.
I chose to concentrate on the latter assumption as if I was right, it required the least work to fix. I was wrong and every alternate way I tried of taking neutral to the sub main db resulted in a worse trip scenario.
Turned out I had connected the downstairs lights and geyser to the wrong neutrals...took a while to trace, but all is now working 100% as expected. I also worked out that the strange wire going through the DB without connecting to anything other than neutral (see previous post where I asked about it) is related to the geyser. Apparently, or so I've been told, it's something to with Eskom turning off your geyser when they like.
Anyway, still to do:
1 ) blanking plate for main DB.
2 ) trunking between battery and inverter.
3 ) end cap for trunking at inverter.
4 ) warning labels, and proper db board labels coming soon
5 ) finish ICC Pi install, and not just sat on battery box.
6 ) surge arrester for PV.
7 ) replace PV cutoff switch (only large enough for 6mm cable, so for now I've had to limit PV charging to less than 40A)
8 ) install indicator lights in db board.
9 ) anything I've forgotten to mention here
And finally some progress pics.

From what I have gathered on the forum, a CT clamp is not the panacea it seems to be, if you have the wrong type of meter.
The lagging response time when a load switches off, means the temporary power export still causes nuisance trips of the meter.
I don't have one of these type of meters, so I am sure a CT clamp would work OK for me.
If you have any purely resistive heat loads they can be fed by a load diversion DC PWM set up once the batteries are charged. This is what they use to power dump loads with wind generation.
This is probably the best solution in your set up to capture the lost production.

Patched firmware for some of the MKS models allows you to independently display an "input" value and an "output" value. Some things like battery voltage can be displayed on either or even both. It is possible to display the combination @Micdemas requested. But there is no patched firmware for the MKS II models.

I'm pretty sure the MKS II screen is identical to the MKS screen, and in that case, you cannot display PV in power and total output power simultaneously, unless there is a firmware which allows this? @Coulomb

As the others have said, it is normal. SOC is always a numerical estimation of a physical system, and there is always a bit of drift. It is normal for the SOC to be off by some margin, and for a "reset" to cause a jump at the top. The one thing we know for sure about batteries is that 1) the voltage rises and 2) the current drops when they are full, so most battery monitors will look for that event, and then reset, which corrects any drift there might have been since the last time the battery was full. These jumps will be smaller if the battery is regularly charged fully.

Yes its normal

Thanks for commenting @Gerrie.
I won't go as far as changing out this DB for a bigger one, reason being is I'll be moving the last 3 breakers from the right hand side (Plugs and 2x Lights) to a separate DB board on the other side of the wall which will house all of the essential circuits, while this DB will only house breakers for non-essential circuits. I will also change the MAINS breaker to a double which can disconnect neutral and live together, rather than just disconnecting live as it does now. Not sure how legal it is at the moment, but I suspect it was done when they fitted the second geyser.
Anyway, I'm done with the main DB board for now. Fixed the daisy chain, replaced with a 63A busbar, and most of the breakers are now the same (couldn't fit the busbar with the mixture of Majortech and ABB breakers, so just populated all with what I have.)

Also started moving the PV wiring from the garage side of the house over to where the inverter is installed.

Sold.

SANS allows a shared neutral in a few cases: If the "standby power" feeds in "at main supply", then you are allowed such things. It's figure S.1 in Annex S of SANS-10124-2-1.

In your case, since you're feeding only a part of the installation, you must split the neutrals.