PeterP

We AC coupled 2.76kWp of panels on an old 2kW grid-tie inverter via the Gen port on a 8kW Sunsynk yesterday. It is working perfectly. it switches the grid-tie inverter with frequency shifting so you can set at what battery SOC% you want it to switch off and back on. You can also restrict grid-feedback without adding another CT clamp. The grid-tie inverter continues working during loadshedding as the inverter frequency makes it believe it's still has grid. Very neat solution.
Cheapest way to do it is if you have an old un-used grid-tie inverter floating around. If you don't have a cheap grid-tie lying around i would recommend just adding another 8K Sunsynk in parallel - or you could use the 5K Sunsynk AC-coupled but the benefits of having another 8K in parallel probably outweighs the price difference

Reducing consumption of electricity by changing to gas cooking makes no sense unless we're looking at 100% off-grid set-up with no Eskom supply. Firstly, you incur capital expenditure setting it all up, secondly, you will merely move the expense of electricity over to purchasing of gas, thirdly, you are now at the whims of gas supply and travelling around to get it plus over time it is likely to go up in price and lastly you will continue to contribute CO2. Unless you enjoy cooking on gas or already have a gas stove, I would not change, rather spend a little more on the PV system.
 

You are currently making good return and your system will have a very high IRR, but it seems you are exporting more than what the CoCT SSEG system allows for (ie you are not currently a net consumer). Net consumer is calculated on annual consumption and production so you might still be ok once winter is taken into consideration, but seeing your impressive tracker results, I'm not sure
You are missing my point about having the option to add batteries, of course it will be more expensive and thus IRR will be potentially reduced but batteries are all about having power when Eskom can't supply - for most people (not you), eliminating loadshedding, is as important as the ROI. On a small residential system the Hybrid inverter may add R10K up-front, but then you are at least able to add batteries at a later point if the feed-in tariff is reduced (or eliminated) - or loadshedding ramps up even more.
One of the main problems with CoCT SSEG feed-in system is that you are effectively entering into a 1 year contract with the City on your 20-25 year solar investment. The monthly SSEG connection fee, tariff and feed-in tariff are changed annually which means your system IRR is very vulnerable, especially if it is dependent on the feed-in, to achieve savings (eg. City may only offer R0.33/kWh feed-in next year or R0.10/kWh or none at all.....). The R0.25/kWh incentive is for first year only and may not even apply to systems added in future years. If CoCT would offer a feed-in deal fixed for 5 years then we'd be able to do our sums and make much more informed decisions.
With a self-consumption battery system you will fix your R/kWh rate for life of system (currently R1 - R1.50/kWh) so it's a bit easier to work out the IRR as the Eskom kWh tariff historically has only ever gone up. Feed-in tariffs world-wide have mostly been coming down.
Currently, hybrid battery system in Cape Town expected pay-back is 5-8 years, grid-tie SSEG can be as low as 3-4 years (but no grid - no worky).

As most might know by now, Sunsynk will be launching their own monitoring dongle, which gives access to all settings. We have one in beta testing and so far it's looking pretty good. Not sure when they will be broadly available, though. I'd imagine they'd want people to use their proprietary solution over Solarman's - and that would answer your question.

From Sunsynk:  In time of use set power= essential load, so at night only that much power it will discharge from battery and remaining from Grid , At day time solar will provide both essential and non essential, You need to to Click on zero export only not Zero export to load, Else solar won't provide supply to non essential

If solar is less then battery will provide supply to non essential till it will reach SOC, you can control this by Setting % in time of use , suppose you have set 95% then battery will discharge only 100-95% at day time and if you set 20% for night then battery will discharge to 20% in night.
So the Sunsynk will supply battery power to non-essentials. 

If you limit the battery discharge power in System Mode surely this is supposed to limit battery discharge to essential loads only? As I understand it, non-essential loads are not supposed to get power from anything but grid and excess PV, having said that we have one site doing just that (battery power to non-essential loads) and we've been told it will be fixed with a firmware upgrade. I sense there is a lot of confusion around this, and I, for one, am not sure how it is intended to work as we've seen both....

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.

1) I don't see the reason to switch anything to gas unless that is your absolute favored way of cooking or you want to have redundancy solution in case your PV trips out. Heating anything, but especially water with gas is more expensive than solar or solar PV will ever be + it's polluting + potentially a fire/explosion hazard + you have to replace cylinders when they run out + gas will go up in price over life of your PV system. Rather get a little more PV and storage and some energy efficient appliances.
2) Parasitic loads can make up a large portion of our night time loads eating away at the battery capacity. Switch off and unplug everything that is not absolutely essential and you'll be astounded how much you can save. Even 300W over 10 hours x 30 days adds up to 90kWh over a month. I have wired TV, amplifier etc etc so that I can switch it off on the wall when we go to bed - just get rid of all those little red standby lights and you will save 100-300W easy.
3) Water heating - get a bigger tank and low-flo shower heads and use your PV to heat it up. Some days there won't be enough sun, that's when Eskom will have to step in.

1) I don't see the reason to switch anything to gas unless that is your absolute favored way of cooking or you want to have redundancy solution in case your PV trips out. Heating anything, but especially water with gas is more expensive than solar or solar PV will ever be + it's polluting + potentially a fire/explosion hazard + you have to replace cylinders when they run out + gas will go up in price over life of your PV system. Rather get a little more PV and storage and some energy efficient appliances.
2) Parasitic loads can make up a large portion of our night time loads eating away at the battery capacity. Switch off and unplug everything that is not absolutely essential and you'll be astounded how much you can save. Even 300W over 10 hours x 30 days adds up to 90kWh over a month. I have wired TV, amplifier etc etc so that I can switch it off on the wall when we go to bed - just get rid of all those little red standby lights and you will save 100-300W easy.
3) Water heating - get a bigger tank and low-flo shower heads and use your PV to heat it up. Some days there won't be enough sun, that's when Eskom will have to step in.

Speaking of spelling mistakes, you've got a screamer going on there 😉

You are currently making good return and your system will have a very high IRR, but it seems you are exporting more than what the CoCT SSEG system allows for (ie you are not currently a net consumer). Net consumer is calculated on annual consumption and production so you might still be ok once winter is taken into consideration, but seeing your impressive tracker results, I'm not sure
You are missing my point about having the option to add batteries, of course it will be more expensive and thus IRR will be potentially reduced but batteries are all about having power when Eskom can't supply - for most people (not you), eliminating loadshedding, is as important as the ROI. On a small residential system the Hybrid inverter may add R10K up-front, but then you are at least able to add batteries at a later point if the feed-in tariff is reduced (or eliminated) - or loadshedding ramps up even more.
One of the main problems with CoCT SSEG feed-in system is that you are effectively entering into a 1 year contract with the City on your 20-25 year solar investment. The monthly SSEG connection fee, tariff and feed-in tariff are changed annually which means your system IRR is very vulnerable, especially if it is dependent on the feed-in, to achieve savings (eg. City may only offer R0.33/kWh feed-in next year or R0.10/kWh or none at all.....). The R0.25/kWh incentive is for first year only and may not even apply to systems added in future years. If CoCT would offer a feed-in deal fixed for 5 years then we'd be able to do our sums and make much more informed decisions.
With a self-consumption battery system you will fix your R/kWh rate for life of system (currently R1 - R1.50/kWh) so it's a bit easier to work out the IRR as the Eskom kWh tariff historically has only ever gone up. Feed-in tariffs world-wide have mostly been coming down.
Currently, hybrid battery system in Cape Town expected pay-back is 5-8 years, grid-tie SSEG can be as low as 3-4 years (but no grid - no worky).

You are currently making good return and your system will have a very high IRR, but it seems you are exporting more than what the CoCT SSEG system allows for (ie you are not currently a net consumer). Net consumer is calculated on annual consumption and production so you might still be ok once winter is taken into consideration, but seeing your impressive tracker results, I'm not sure
You are missing my point about having the option to add batteries, of course it will be more expensive and thus IRR will be potentially reduced but batteries are all about having power when Eskom can't supply - for most people (not you), eliminating loadshedding, is as important as the ROI. On a small residential system the Hybrid inverter may add R10K up-front, but then you are at least able to add batteries at a later point if the feed-in tariff is reduced (or eliminated) - or loadshedding ramps up even more.
One of the main problems with CoCT SSEG feed-in system is that you are effectively entering into a 1 year contract with the City on your 20-25 year solar investment. The monthly SSEG connection fee, tariff and feed-in tariff are changed annually which means your system IRR is very vulnerable, especially if it is dependent on the feed-in, to achieve savings (eg. City may only offer R0.33/kWh feed-in next year or R0.10/kWh or none at all.....). The R0.25/kWh incentive is for first year only and may not even apply to systems added in future years. If CoCT would offer a feed-in deal fixed for 5 years then we'd be able to do our sums and make much more informed decisions.
With a self-consumption battery system you will fix your R/kWh rate for life of system (currently R1 - R1.50/kWh) so it's a bit easier to work out the IRR as the Eskom kWh tariff historically has only ever gone up. Feed-in tariffs world-wide have mostly been coming down.
Currently, hybrid battery system in Cape Town expected pay-back is 5-8 years, grid-tie SSEG can be as low as 3-4 years (but no grid - no worky).

You are currently making good return and your system will have a very high IRR, but it seems you are exporting more than what the CoCT SSEG system allows for (ie you are not currently a net consumer). Net consumer is calculated on annual consumption and production so you might still be ok once winter is taken into consideration, but seeing your impressive tracker results, I'm not sure
You are missing my point about having the option to add batteries, of course it will be more expensive and thus IRR will be potentially reduced but batteries are all about having power when Eskom can't supply - for most people (not you), eliminating loadshedding, is as important as the ROI. On a small residential system the Hybrid inverter may add R10K up-front, but then you are at least able to add batteries at a later point if the feed-in tariff is reduced (or eliminated) - or loadshedding ramps up even more.
One of the main problems with CoCT SSEG feed-in system is that you are effectively entering into a 1 year contract with the City on your 20-25 year solar investment. The monthly SSEG connection fee, tariff and feed-in tariff are changed annually which means your system IRR is very vulnerable, especially if it is dependent on the feed-in, to achieve savings (eg. City may only offer R0.33/kWh feed-in next year or R0.10/kWh or none at all.....). The R0.25/kWh incentive is for first year only and may not even apply to systems added in future years. If CoCT would offer a feed-in deal fixed for 5 years then we'd be able to do our sums and make much more informed decisions.
With a self-consumption battery system you will fix your R/kWh rate for life of system (currently R1 - R1.50/kWh) so it's a bit easier to work out the IRR as the Eskom kWh tariff historically has only ever gone up. Feed-in tariffs world-wide have mostly been coming down.
Currently, hybrid battery system in Cape Town expected pay-back is 5-8 years, grid-tie SSEG can be as low as 3-4 years (but no grid - no worky).

You are currently making good return and your system will have a very high IRR, but it seems you are exporting more than what the CoCT SSEG system allows for (ie you are not currently a net consumer). Net consumer is calculated on annual consumption and production so you might still be ok once winter is taken into consideration, but seeing your impressive tracker results, I'm not sure
You are missing my point about having the option to add batteries, of course it will be more expensive and thus IRR will be potentially reduced but batteries are all about having power when Eskom can't supply - for most people (not you), eliminating loadshedding, is as important as the ROI. On a small residential system the Hybrid inverter may add R10K up-front, but then you are at least able to add batteries at a later point if the feed-in tariff is reduced (or eliminated) - or loadshedding ramps up even more.
One of the main problems with CoCT SSEG feed-in system is that you are effectively entering into a 1 year contract with the City on your 20-25 year solar investment. The monthly SSEG connection fee, tariff and feed-in tariff are changed annually which means your system IRR is very vulnerable, especially if it is dependent on the feed-in, to achieve savings (eg. City may only offer R0.33/kWh feed-in next year or R0.10/kWh or none at all.....). The R0.25/kWh incentive is for first year only and may not even apply to systems added in future years. If CoCT would offer a feed-in deal fixed for 5 years then we'd be able to do our sums and make much more informed decisions.
With a self-consumption battery system you will fix your R/kWh rate for life of system (currently R1 - R1.50/kWh) so it's a bit easier to work out the IRR as the Eskom kWh tariff historically has only ever gone up. Feed-in tariffs world-wide have mostly been coming down.
Currently, hybrid battery system in Cape Town expected pay-back is 5-8 years, grid-tie SSEG can be as low as 3-4 years (but no grid - no worky).

The Hybrid will still require a battery to function during grid-outage - panels will give no power. The reason to start with Hybrid is to give you the option to add battery later instead of having to buy a new inverter once you decide to do so. The Hybrid will export and work while grid is up like Erastus system at a fractionally higher upfront cost but with the added benefit you can add battery at any time (which anyone with a grid-tie only system would ultimately love to have when there is loadshedding...)

ROI is typically the single most important factor when considering going solar - even though being Loadshedding resilient and producing clean energy are close seconds and thirds.
The screenshot gives our savings on a 5.6kWp (320W modules) - 10KVA (Axpert inverters) - 13.5kWh (Solar MD Li-Ion Battery) for the past 3.5 years. Cost of system R200K. Annual solar savings: R25K+
What it doesn't show, is that we have further estimated savings of R25,000-R30,000 per year in avoided petrol purchases and vehicle maintenance as the system is also powering our Nissan Leaf EV. We use the electric vehicle for school runs, daily shopping and the odd meetings/outings and are able to have it on the solar powered plug for 3-4hours per day.
Standalone the solar system will pay for itself in 6-8 years but adding the car doubled the ROI of the solar system.

ROI is typically the single most important factor when considering going solar - even though being Loadshedding resilient and producing clean energy are close seconds and thirds.
The screenshot gives our savings on a 5.6kWp (320W modules) - 10KVA (Axpert inverters) - 13.5kWh (Solar MD Li-Ion Battery) for the past 3.5 years. Cost of system R200K. Annual solar savings: R25K+
What it doesn't show, is that we have further estimated savings of R25,000-R30,000 per year in avoided petrol purchases and vehicle maintenance as the system is also powering our Nissan Leaf EV. We use the electric vehicle for school runs, daily shopping and the odd meetings/outings and are able to have it on the solar powered plug for 3-4hours per day.
Standalone the solar system will pay for itself in 6-8 years but adding the car doubled the ROI of the solar system.

Current SA EV prices are ludicrous - we got ours 2nd hand for R193K with 35K on clock - so then it's ok. Future EV pricing will be in line with ICE in a few years. We had to replace the other car anyway, so for us it made sense.

Current SA EV prices are ludicrous - we got ours 2nd hand for R193K with 35K on clock - so then it's ok. Future EV pricing will be in line with ICE in a few years. We had to replace the other car anyway, so for us it made sense.

ROI is typically the single most important factor when considering going solar - even though being Loadshedding resilient and producing clean energy are close seconds and thirds.
The screenshot gives our savings on a 5.6kWp (320W modules) - 10KVA (Axpert inverters) - 13.5kWh (Solar MD Li-Ion Battery) for the past 3.5 years. Cost of system R200K. Annual solar savings: R25K+
What it doesn't show, is that we have further estimated savings of R25,000-R30,000 per year in avoided petrol purchases and vehicle maintenance as the system is also powering our Nissan Leaf EV. We use the electric vehicle for school runs, daily shopping and the odd meetings/outings and are able to have it on the solar powered plug for 3-4hours per day.
Standalone the solar system will pay for itself in 6-8 years but adding the car doubled the ROI of the solar system.

ROI is typically the single most important factor when considering going solar - even though being Loadshedding resilient and producing clean energy are close seconds and thirds.
The screenshot gives our savings on a 5.6kWp (320W modules) - 10KVA (Axpert inverters) - 13.5kWh (Solar MD Li-Ion Battery) for the past 3.5 years. Cost of system R200K. Annual solar savings: R25K+
What it doesn't show, is that we have further estimated savings of R25,000-R30,000 per year in avoided petrol purchases and vehicle maintenance as the system is also powering our Nissan Leaf EV. We use the electric vehicle for school runs, daily shopping and the odd meetings/outings and are able to have it on the solar powered plug for 3-4hours per day.
Standalone the solar system will pay for itself in 6-8 years but adding the car doubled the ROI of the solar system.

The CoCT Residential SSEG tariff shown is only for customers who feed-in - if you are not feeding in, you pay the same Energy Charge but a reduced Service charge of R171 VAT incl. pm. on Home User Tariff. 

Reducing consumption of electricity by changing to gas cooking makes no sense unless we're looking at 100% off-grid set-up with no Eskom supply. Firstly, you incur capital expenditure setting it all up, secondly, you will merely move the expense of electricity over to purchasing of gas, thirdly, you are now at the whims of gas supply and travelling around to get it plus over time it is likely to go up in price and lastly you will continue to contribute CO2. Unless you enjoy cooking on gas or already have a gas stove, I would not change, rather spend a little more on the PV system.
 

Plonkster is pretty close - the retail price for Solar MD 3.7kWh battery (complete - no extra cables, enclosures etc needed) is R28,800 excl VAT. Add R3,500 for the logger if monitoring is required.
Battery is compatible with any 48v battery charger/inverter and logger can be used with an increasing number of inverters - Axpert, SMA, MLT, Victron, Microcare, Studer, Sungrow, and Imeon.
Most retailers sell systems and then the pricing gets a bit more fluid depending on total system sizing.
The package is impressive and very installer friendly + the guys are constantly tweaking and improving software in logger and BMS + making logger compatible with more inverters.

This forum thread is still going! 
Well, this is actually a change because another department was reading it too literally! The SSEG side does not care about the Off-Grid sizing, but due to the wording in the SSEG Guidelines another department started rejecting declarations (note the work here, DECLARATIONS). So the SSEG guys just made a minor change to it.
So where you are truly off-grid, you declare and note that it is not on the grid.
For those on Axpert, you limit your charging to 15A and be done with it, now... Again had to talk to various people to get this understanding.
Seems enough people complained, and once CoCT departments started speaking they realised the problem! 
Lets hope the other Munics follows! I know a lot of people are really pissed off at Drakenstein! (But that was their changes to the feed-in/credit tariff)! 
Also, might be good to note:
Off-Grid: Never have Grid and Solar connected at same time. When Batteries are low and Solar not sufficient it CAN change over to Grid-Only [Not parallel to Grid]
Hybrid: Has batteries and Solar, can export to the grid and can have Grid and Solar at the same time on the Output [Parallel to Grid in normal operation, continue to operate at grid outage]
Grid-Tied: No Batteries, Grid and Solar on output [Parallel to Grid in normal operation, stop operation at grid outage]
 
Hybrid Off-Grid is a confusing term and not usually defined by Inverter Manufacturer.