flatfourfan

Here is an example with 400W panels:
https://solar.co.za/how-to-size-a-pv-array#cs3

Rather when you move in and can control and monitor it would be my suggestion.
It does give you time to get the best deals on the hardware in the meantime.
 

Feel your pain @Muttley am off-grid 90% of the time and have more power than I can use, is just those three days a month.
Seems crazy to get more panels to just get through those three days when I can just run of the grid

Looking at that graph, it seems like you are exporting, and as most meters are configured, you will be paying for that export the same as import. The fact that the grid power is measuring 0 means something is mis-configured/wired incorrectly.

We've been going now for about a year, so I can add some stats. In the beginning it took us about a month to play around a bit with the system and what pulls and when it pulls. We've also had all four seasons go by too. 
2023 - Gone from pulling 88.6kWh a month from the grid to
2024 - Currently pulling 18.1kWh a month from the grid
We have some weeks where we will pull 0kWh from the grid and will produce between 25/30kWh a day from solar.  We're on prepaid my wife just loads R50 on each month, just to keep the man happy and to keep some credits just in case. 
When the sun is like it is today, I load it, dishwasher, both geysers (3000w + 3500w), 1000w pool pump, fridge/ freezer, anything that I can throw at it and the sunsync 8kw inverter just takes it. I'm yet to find the peak of what I can use. I've even had the welder and lawnmower on with all of the above and no problem.  
My system reckons I've saved about R21 000 in this period. 
 

We've been going now for about a year, so I can add some stats. In the beginning it took us about a month to play around a bit with the system and what pulls and when it pulls. We've also had all four seasons go by too. 
2023 - Gone from pulling 88.6kWh a month from the grid to
2024 - Currently pulling 18.1kWh a month from the grid
We have some weeks where we will pull 0kWh from the grid and will produce between 25/30kWh a day from solar.  We're on prepaid my wife just loads R50 on each month, just to keep the man happy and to keep some credits just in case. 
When the sun is like it is today, I load it, dishwasher, both geysers (3000w + 3500w), 1000w pool pump, fridge/ freezer, anything that I can throw at it and the sunsync 8kw inverter just takes it. I'm yet to find the peak of what I can use. I've even had the welder and lawnmower on with all of the above and no problem.  
My system reckons I've saved about R21 000 in this period. 
 

I know someone who thought they would save money going gas hot water. Gas costs him R1000 a month. 
Gas geyser same price as evacuated tube solar geyser that I have had for 12 years. Only have to use electricity in winter and really cloudy days to heat it a little or I just leave the element breaker off. 
The new solar geysers are so efficient. Mine is outside on the roof and in winter it's still warm enough to shower the next morning. 

Just got my install finished on Fri 12th Nov 2021 - can't wait for load shedding... 🙂
SunSynk 8kW inverter 4 x Hubble AM2 5.5kWh ~20kWh 16x400W Seraphim 6.4kWp in 2 strings of 8 JHB South, North facing, roof slope is ~23° Evacuated Tube Thermosiphon Solar Geyser Solar-Assistant RPI3b


I have the RIOT and the "Older" SolarMan WiFi
RIOT does not seem to work with the SunSynk 8kW inverter at this stage 😞

Since I had a RP3b lying around I've also tried Solar-Assistant.
So far Solar-Assistant is my preferred tool as it works locally and cloud with a rich data and access to mqtt.

Actually the better way to have the penalty clauses. We would have less projects taking many years to complete if Gov can master this art. 
Well done on a nice project for you. You just have to keep coming back up north.

No the group Shoprite Holdings Limited pays 60% in advance then gives you a guaranteed letter for the balance but in the contract there is a penality clause so for every day late they deduct money from the 40% that was another factor i was stressed, initially i was behind on the procerument but fortunately i finish up few days to spares as the deadline is Friday the 8th. I still need to place and connect the genset to the installation but i have ample time before "D" day. So no bottles involved🤣
 

We used a boom lift similar to this one ladders becomes a safety risk at these heights.
 

They only need power during daytime as the fridges/ freezers when not constantly opened is not a problem until sun comes up so the 2 or 4 hours load shedding not a problem. The generator would be coupled via a central thermal unit monotoring the freezers temp and when drop of 8° the gen will activate. 

At last done with this installation got a few more gray hairs. Installation done at OK Liquor outlet in Witbank( Emalahleni). Total power consumtion during daytime 23kw mostly commercial fridges , upright freezers and some upright wall chillers. Will install 35kva Perkins generator that will arrive on Monday morning. 5kw Growatt and 48v 100ah Easy Power lfp that will run the office equipment.
Scneider CL33 inverter 33kw surge 40kw 2 minutes that is capable of DC-AC ratio of 1:9. The CL 33 inverter will deliver full power at unity power factor with +30% and -5% grid
voltage variation. MPPT voltage range: 200 ~ 1200 V
Full MPPT voltage range: 550 ~ 1000 V
Maximum voltage: 1500 V
Starting voltage: 250 V.                            Number of MPPT's:  3
Solar array consists of 138 x Seraphim 460wp connected 23S6P 63.48kwp.Voc of 1050v @ -13°C at STC 955v.

Now we begin the wiring & also for FreedomWon to dismantle the 40/32 HV for us to move in smaller segments. 

The ATESS design team have made one solid industrial grade machine. The magic of pure transformer based design gives me a lot of confidence. 

Logistical intensive installation on the 1st floor of a 100yrs old building. Only a 50kW backup power solution but with a lot of room for expansion. First of all the HPS50 weighs 610kg & most of that weight is concentrated in the large transformer. The transformer comes in at 550kg. So this was a job that we need to separate the transformer otherwise we could not handle such a massive machine at such a critical weight up a staircase that narrows & turns through 180°.
Given the correct tools we accomplished our task. Now for the wiring & for the distribution. Will post more as this unfolds.

I just went through this exercise...Remove panels, paint 2 coats, reinstall...
It took me and 2 others 1hr to remove 8 panels.
Prepare for paint, paint, dry, 2nd coat..
Reinstall panels, also took 1 hr.
Sad thing is I found where the installer had taken shortcuts on connecting the rails. There is a small connector that slides into the end of the rail to connect them. He did not use them and I could not see when inspecting because they were covered by panels.
Lesson....Inspect each phase of the install.
Roof
1) Placement of brackets to rafters/beams...Make sure tiles are in tact and repositioned correctly. Also correct spacing and insertion of brackets
2) Make sure rails are installed correctly, all joins dealt with
3) Panels are installed correctly, wiring tidy and placed in conduit if that i what you required.
 

So we over the line with this installation. Was interesting to work with Solar MD batteries again. We struggled a bit to get CANbus Comms realized because we have 2 different versions of the Solar MD battery. The previous installation was a 5kW Axpert & as can be seen in the Pics this is a 3 phase Eskom Supply. The DB was a bit of a mess & non compliant even though there as a Certificate of Compliance. You can clearly see a 3 phase MCB & Isolator but there is a Single phase Neutral attached to the Isolator. So we had to rewire to 2 x Single Phase isolators. 
2 x extra days to clean this up & revert to pure 3 phase operations & carry out a Non essentials split. CoC inspection tomorrow then final pics to follow. 

This is a Roman tile bracket. Some of the Valsa Brackets require one to drill through the slate & then have a Gasket on both sides. I prefer a more non invasive way. After working on many slate roofs I have found that this tile bracket works perfectly. I have also advised Valsa accordingly & they admitted they did not know it could be used in this way. Provided the Bitumen seal is covering the cut area, the roof is sealed & the bracket works mechanically in the exact same way. It attaches to the Truss.
We are done with mounting the panels. 
The pitch on this roof is insane...

This installation is an upgrade from a single phase 5kW Axpert now pairing to a 12kW 3 phase Deye. One particular aspect of interest to most people is that there are 2 x 7.4kWh Solar MD batteries and most ppl will think that this is enough to run a 12kW Deye inverter. Unfortunately not fully able to run the Deye to full capacity of 12kW. The Solar MD is not 1C. Each Battery can only deliver 5kW max power. Meaning the Deye will behave like a 10kW machine when no sun shine & no grid. 
The owner was shocked & said nobody told him about this when he purchased them. The devil is in the details...Pay attention to C rating it's important!

About to start an upgrade to an existing Single phase backup & transform to a 3 phase installation with some good upgrades in terms of PV power & battery integration. Unfortunately there are not enough Solar MDs to make up a 12kW Continuous discharge but a good start. The batteries limit this installation to 10kW 3 phase output when the sun is down. 
More pics to follow...
Another slate roof to challenge ourselves on...
North is right of picture so we plan to install 7 east & 7 west on the big MPPT. There is an existing array on the North side which is not shown. 
 

Your best immediate option is to max your inverters PV input. I would also consider a solar geyser with 2kw backup element. 
When you talk about ROI are you factoring in that in 5 years time electricity will probably be double the cost that it is now? 

so looking at that graph, there is a LOT of meat still left on the bone in order to reduce your eskom usage by quite a bit more you know? What % are you running the battery down to? I'm thinking that a little more PV could make a serious knock in your 08h00-14h00 usage. 

Looking at your graph. Don't think there's sense at all to run down the battery as long as the daytime consumption exceeds your solar generation because you'll just have to replenish charge from the grid and that ultimately costs more. Loadshedding the obvious exception.
 
But if you have say 10kWh of storage, there looks to be scope for 2-3kW of additional panels to help generate more in the day to use from storage later and at night.

Very well balanced system between use and production. Thanks for sharing. 

So been on the sun proper since July '23 and I honestly thought that the winter months would be my worst, but unless it's been a total cloud day, then it's actually been above okay. I've also been educating myself with what the system can and cannot do. 
Prior to solar our household was using around the 450-600kWh a month, but yeah that's expected with two teenage girls and a wife that doesn't really share the passion of saving. 
Currently August was my best month with a 669kWh pull from the sun and only 10.7kWh from eksdom, Prior to that we were doing mid 500'skWh and about 1/10th of that coming from eskom. The family is on board now. Wireless Cbi timers on my pool and geysers have allowed me to pretty much run 95% of my house from the sun. 
I wake up to around 45% of my batteries that are used to just top up the geysers in the morning and my day at 7am normally starts on 25% or pretty damn close to it. Hey, you try and have a household of three woman having to have cold water..............it's a price that I'm willing to pay. 🙂
Just had my best pull day yesterday of 28kWh for the day from the sun. I'm actually struggling to find more pull, I know that once the rains start and my mower, then that'll be another 2-3kWh pull......I hope. 
12 x 470w Jinko panels,
8KW Sunsynk inverter
2x 5.5KV greenrich batteries