FransSmith

Way wait - simply switch off your grid power for a few hours, let the battery drop to (say) 70%, then switch the grid back on and observe the charging amps. Given that you will be charging from the grid in any case, you could do this in the late afternoon/early evening when you're at home to observe.
I'm a great fan of not discharging batteries deeply unless absolutely necessary (i.e. grid failure), but I also believe that keeping a lithium ion battery fully charged (at 100%) for long periods will negatively affect it's service life. Given that you have a number of charge and discharge time slots available, I would consider partially discharging the battery every day - say down to 70% SOC. If you have varying grid cost rates (i.e. a very expensive peak time rate and a much lower off-peak rate), you could set the system to discharge during the high-rate periods and charge fully again during the off-peak periods - this is known as "grid shaving", feel free to Google this term for more info.

Thank you kindly for the response. I changed my 8kw to a 10kw with 3 x MPPT and installed a string of 7 x 610w East so I have a overdesigned system, but I will benefit greatly in the winter months

I have a 8kw Sunsynk inverter with 12 x 550 Jinko panels in 2 strings
During winter my panels get shade from my neighbours trees
Will Solar Optimisers help and are they compatible with Sunsynk?

Google and get more details than we can perhaps provide. 
Without the detail of direction of the strings and what time of day and for how long you have shade makes it difficult to give guidance. 
Here is a starter to read. 
https://www.energysage.com/solar/string-inverters-power-optimizers-microinverters-compared/

@FransSmith,
You need to check what the default charging Amps is on the inverter.  A value of 60A (20A per battery) would be a safe/sensible number. If your batteries are charging @ 3500W, it means (3500/54) = 64 Amps, so that is OKish. You can set it higher (in 5A increments), but remember, the harder a battery is charged, it shortens the lifespan. So you pick your battles....I suppose the charge rate in every scenario is different, specially when there's lots of load shedding around.
My preference is:
No/little loadshedding/good sunshine => 20A per battery (no grid charge allowed)
Med. loadshedding/intermittant => 30A per battery (maybe 1 timer interval Grid charge allowed)
High Loadshedding/100% overcast => 40A per battery (2 timer intervals allowing Grid charge)
Just a guideline, ramp up or down to suit your environment/requirement.
The depth of discharge (SOC%) is also an factor, the lower your SOC at sunrise, one may need to adjust the charging rate accordingly.

SARS will make ORDERS more on the VAT they collect (from your typically installed inverter, battery & solar panel system) than the misery 15K MAX tax rebate on the panels.

Never heard of an ECCO Hybrid, except in in the model designation of a certain Luxpower range. Where did you hear about it? Examples? 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

I have been trying to make sense of this post.  Please help.
I assume that the 5M you refer to is 5MW (megawatt).
I assume that 40M is in fact 40m (metres), and 8M is 8m.  I further assume that the 605W you refer to is a 605W panel.  The only one I can find is a Jinko RS600M-120HC - they measure 2172mm x 1303mm.  You could fit a theoretical maximum of 113 into an area 40m x 8m if you packed them without gaps to avoid shading, more like 40% of that in practice.  "Easily 120" would be a stretch - perhaps I have misunderstood you?
By 7.2 KWhr I assume that you mean 7.2kWh.  I do not understand that - 120 x 605W would be about 72kW.   (Expressing power output in kWh makes no sense unless you attach a time dimension to it.)  Did you mean to say 7.2kW?  If so it should have been 72kW.
So, (making many assumptions) is this what you were trying to say?
"I have a space of 40m x 8m where I could fit in 72kW of PV using 120 x 605W panels".  It would not be quite true, but OK.
Forgive me if I am being too pedantic, but there are many people who read these forums who are not technically educated - the conversation will be more easily understood by all if we so not each invent our own abbreviations.

I probably need to say why I want to do this DIY - do it yourself. Those panels are expensive and leak and break - been there done that. A heat pump with PV is probably going to be just as expensive.  And I want to do a DIY build.
So any advice on how to accomplish this as a DIY project?

Hahaha. Hey Frans. How are you? Can’t “brag” yet. We need to install the last inverter. 

Another Sunsynk install with 4 x AM3’s. Each AM3 is 2.75kwh. 
 
Will complete it on Wednesday. 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

used to have a Fronius 20 kw 3 phase inverter with 26 x 305 watt panels
upgrade =
3 x 5kw Sunsync
with extra 9 x 390 watt panels (total of 35 panels = 11 440 watt)
and 3 x Hubble 5.5 kw batteries
work in progress
thank you Leshen, Steve and team
 

Good luck - Leshen is installing my 3 x 5kw Sunsynk inverters with 3 x Hubble inverters on Monday  -I believe Leshen is an expert so I am confident we will both have good "mileage" from our systems

Wow, that was quick!

You could potentially do this with "smart" switches that will proportionally send power to the geyser(s) only once you start to export power to the grid, and only the amount that would of electricity that would have been exported otherwise, the below two products are available locally as far as I know, could be others also:
Solic200 - Single channel unit, no programmable timer
https://re-volt.co.za/Store/index.php?route=product/product&product_id=636
Apollo GEM - Dual channel unit wit a programmable timer, can also be fitted with a temp sensor.
https://www.apollosolarelectric.co.uk/products/ - Got mine from Rubicon in Cape Town, dealt with Nick Roche there
 
 

Thank you. I appreciate it. Works really well. I have a peak power production of 9000w on a 9360w array. The array is approx 30m from the inverter so I’m happy with that production. On a sunny day I produce close to 50kwh a day. 

Maybe suggest to the forum admin that people should STOP suggesting Sonoff switches. Don’t agree with it being a “shit” idea. Mine works fine.