Gerrie

I don’t think flickering of lights is normal, my own lights make a slight flick when changing over.
 
I noticed the 60A is your inverter set to charge the pylontech at 60A? if so, I think it’s to high for a US2000 it should be set at 25A the same as recommended discharge current, otherwise you might shorten the battery lifespan.

Thanks, Yes it did take longer than a single 48KW unit, fortunately roof repairs and painting was also done and gave me some extra time inbetween string installations. The amount of cables and other materials were also more than for a single unit, I absolutely loved doing this install and switching on one by one string makes it all worth it.

If you have them in parallel one will be the master and one the slave inverter, you only set settings on the master inverter and they will automatically work as one inverter. No need to worry about the slave backfeed as the master will control the setpoint. You also don't need a CT coil for the slave inverter.

Without going into detail your 2 inverters cannot feed each other a grid connection when the grid is down. Each one will sense the grid is down. You also don't set them up to cut the grid connection where the non essential is connected to they do it by default and is one of the requirements before these inverters are approved to be connected to the grid. 
Part of what I mentioned is like your neighbour could be connected to the same phase and so some other houses. When the grid goes down they cannot make all the inverters think the grid is still up and running. 
A bit technical to explain how they all see the grid is down. The CTs plays no part in telling the inverters the grid is down. 
Sorry I did not actually respond to your concerns.

In my opinion the little stand alone trolley does not require a COC, because it just plugs into a wall socket and feed directly to the appliances with plugs. The moment you permanently connect cables to the Installation, you need a COC to comply WIT SANS. 
The same with solar panels, are they just free standing outside and plugged into the trolley or are they fixed to the building. The moment they are fixed you need to consider a COC because it now becomes a permanent installation and require all the proper DC - DB safety requirements like earthing, fuses, isolators and surge protection, labeling etc.
I have done trolley installs and I do them exactly as a normal solar inverter installation connected to the DB feeding the critical loads. The solar panels are mounted as normsl on the roof with DC DB protection, earth rod and the whole lot for COC. Compliance.
 

Great reply Gerrie. 

Something to consider is that a evacuated geyser in S.A. in summer can reach temperatures of 89 degrees celcius before its overtemperature valve opens and dumps the hot water. Feeding this heated water with such high temperature through a heatpump and into the secondary geyser might be problematic as the secondary geyser might not be able to handle 88 degree water and the heatpump might even try to cool the water down to the setpoint of say 55 degrees. I might be completely of mark but my own 200ltr evacuated geyser often in summer dumps about 50ltr of overheated water.
 
Is it not possible that your evacuated geyser also use its element to heat water as per the timer setting? unless the element has been completely disconnected it might explain extra usage. 

@GreenFields
All valid points you raised but to me compliance and safety is key, the environment is too cramped and combustible. What i have seen so far according to the installation specifications there need to be smoke detection above the lfp batteries linked to the fire alarm system and there need to be class D fire extinguishers not more than 2 meters from the battery installation. So careful consideration on the next installation position for inverter, batteries and switchgear.

Thanks, Yes it did take longer than a single 48KW unit, fortunately roof repairs and painting was also done and gave me some extra time inbetween string installations. The amount of cables and other materials were also more than for a single unit, I absolutely loved doing this install and switching on one by one string makes it all worth it.

Eventually finished with the installation of 6 x 8KW Sunsynk inverters and 96 x 555W Longi panels. It has 3 x master and 3 x slave inverters with 12 x 7.4KW BSL lithium batteries. There's also a 100KW generator that can charge the batteries should it be needed. I installed 2 x auto changeover switches, one for Eskom/Generator and the other for Eskom/Inverters. Should the inverters trip for whatever reason the inverter loads will switch over to Eskom, when inverters recover it will auto switch back to battery backup. Should Eskom fail the generator starts and supply all the nonbaked-up loads and the generator will be back-up for the batteries if there's no solar and battery level drops below setpoint.

It would be interesting to know what was the cause of the damage in the first place, as many of us have the exact same 8 kW inverter.
Mine has been through many major lightning storms, failed municipal neutrals, (+300V) lots of spikes, etc, and still working solidly.
Maybe the CoCT has an especially dangerous  grid. 🤔
Sorry to hear about such high labor costs😲, but once repaired, why not hang onto it?

Thanks, Yes it did take longer than a single 48KW unit, fortunately roof repairs and painting was also done and gave me some extra time inbetween string installations. The amount of cables and other materials were also more than for a single unit, I absolutely loved doing this install and switching on one by one string makes it all worth it.

Very nice!

Eventually finished with the installation of 6 x 8KW Sunsynk inverters and 96 x 555W Longi panels. It has 3 x master and 3 x slave inverters with 12 x 7.4KW BSL lithium batteries. There's also a 100KW generator that can charge the batteries should it be needed. I installed 2 x auto changeover switches, one for Eskom/Generator and the other for Eskom/Inverters. Should the inverters trip for whatever reason the inverter loads will switch over to Eskom, when inverters recover it will auto switch back to battery backup. Should Eskom fail the generator starts and supply all the nonbaked-up loads and the generator will be back-up for the batteries if there's no solar and battery level drops below setpoint.

Thanks WannabeSolarSparky and Talia for the advice I will change back to 8xpanels and try to avoid the smoke.

Be careful, cloud edge sun may push you over voltage limits and release the magic smoke. 428v is already close to the max safe recommended 450v.

@Gerrie I would not go above 450v there i must agree with @WannabeSolarSparky. If you calculate temperature Coefficient of Voc for the 555w Longi 0.265%/°C that equates to 26 x 0.265 = 6.89%@0°C. 9 x 49.95 = 449.95v + 6.89% = 480.95v@0°C that would be to high for my hard limit of 50v below maximum dc input voltage. I would rather stick with 8 panel /string not worth the risk by adding 1 panel.

The system has been running just as battery back-up for a few weeks now and we had a few actual Eskom outages for couple of days where the generator setup was put to the test and had to charge batteries when SOC level dropped. I did have a inverter trip of the system in the begining when the charging current was set at full capacity of about 48KW charging for all 6 x inverters plus the rest of the non-essential plant was also pulling another 50KW from generator maxing out at 100KW capacity. The gen frequency was dropping to about 48.5Hz causing the trip, so I played around with charge settings and set inverter charging down to about 24KW where the plant and generator has been happy since. We started installing solar panels and about 60 x panels connected so far and pushing power to inverters so the generator should only kick-in, in real bad solar conditions. I am impressed with the simplicity and the functionality of the Sunsynk inverters and it has been working like a dream sofar.

The system has been running just as battery back-up for a few weeks now and we had a few actual Eskom outages for couple of days where the generator setup was put to the test and had to charge batteries when SOC level dropped. I did have a inverter trip of the system in the begining when the charging current was set at full capacity of about 48KW charging for all 6 x inverters plus the rest of the non-essential plant was also pulling another 50KW from generator maxing out at 100KW capacity. The gen frequency was dropping to about 48.5Hz causing the trip, so I played around with charge settings and set inverter charging down to about 24KW where the plant and generator has been happy since. We started installing solar panels and about 60 x panels connected so far and pushing power to inverters so the generator should only kick-in, in real bad solar conditions. I am impressed with the simplicity and the functionality of the Sunsynk inverters and it has been working like a dream sofar.

The system has been running just as battery back-up for a few weeks now and we had a few actual Eskom outages for couple of days where the generator setup was put to the test and had to charge batteries when SOC level dropped. I did have a inverter trip of the system in the begining when the charging current was set at full capacity of about 48KW charging for all 6 x inverters plus the rest of the non-essential plant was also pulling another 50KW from generator maxing out at 100KW capacity. The gen frequency was dropping to about 48.5Hz causing the trip, so I played around with charge settings and set inverter charging down to about 24KW where the plant and generator has been happy since. We started installing solar panels and about 60 x panels connected so far and pushing power to inverters so the generator should only kick-in, in real bad solar conditions. I am impressed with the simplicity and the functionality of the Sunsynk inverters and it has been working like a dream sofar.

The inverters have been powered up and a few load tests done. The three phase seem to work well. The setting up of master, slave, dip switches, CT coils and phase rotation can play games with you but once right it seem to work pretty well. I have no solar pv connected yet, will start conecting the strings soon, just waiting for some roof work to be completed. I'm excited to see the pv side when connected.

Started installing the inverters. Installing 6 x 8KW Sunsynk inverters and 12 x 7.4KW BSL lithium batteries. Still lots of wiring and hope things go smooth. We decided to go 48KW instead of 24KW to allow for more load on backup. I will post more photos with progress.