Sidewinder

I am using the R3 to switch the old 20A relay.
The Geyserwise main unit would probably be installed at the geyser. But running a small wire for the display is not so bad. Financially the Geyserwise and Geyserwala is not better than my solution, specifically because I had some of the components already.

@Sidewinder
Sunsynk 8kW 9 + 9 JA 550W panels on a single MPPT (overpaneling strategy, current limits & Voc safety)
I’d like to share my configuration and the reasoning behind it, including MPPT utilisation, overpaneling, and cold-condition voltage safety.
System:
Inverter: Sunsynk 8kW inverter (newer revision, 22A MPPT input, 500V max PV voltage)
Panels: 18 × JA Solar 550W.Total array size: 9.9 kWp.
Configuration
MPPT1:
2 × strings of 9 panels (9S2P)
String 1: North-facing
String 2: West-facing
Dual inputs used (internally paralleled).
Electrical Summary
Per string (9 panels in series):
Vmp ≈ 370V
Voc (STC) ≈ 9 × 49.5V ≈ 445V
Imp ≈ 13A
Combined at MPPT:
~26A theoretical vs 22A MPPT limit( ISC per Mppt 44A)
Cold Temperature Voc Check (Critical Design Step)
Using a typical temperature coefficient for Voc: βVoc ≈ -0.28% / °C Temperature delta:
From 25°C (STC) to -5°C = -30°C
Voltage increase: 0.28% × 30 ≈ 8.4% increase. Adjusted Voc at -5°C:
445V × 1.084 ≈ 482V.
Inverter max PV voltage = 500V
Worst-case string Voc ≈ 482V
Safety margin ≈ 18V (~3.6%) below absolute max within safe limits.
No risk of overvoltage trips under expected conditions.
Design Approach & Justification
1. OEM overpaneling allowance
Sunsynk allows 120–150% DC oversizing
This system = 124%. Within recommended range.
3. Overpaneling improves yield better performance under cloud cover, Morning/afternoon low irradiance and
winter conditions. Higher annual energy yield, not just peak output.
4. Orientation diversity
North midday peak West afternoon peak
Reduces simultaneous current and
smoothes generation curve.
5. NOCT-based realism
Real current per string ≈ 10–11A
Combined ≈ 20–22A aligns closely with MPPT limit in practice.
Trade-offs
Occasional clipping at peak overlap
Single MPPT tracking mixed orientations minor mismatch losses.

So I thought I would do a quick update on my progress with getting information from my 8kw OmniVolt.

Happy to report that I have everything I need! All up and running when I workout what addresses were... What pain. But I have uploaded a Modbus reference document for all the addresses I used and what they mean, as well as their unit and scale factor... This should be helpful if anyone needs to get their inverter info into HA .

If you find any errors, let me know and I will update it! I am happy to share my config yaml if anyone needs it, as well as my dashboard yaml.
Ignore the fault... The inverter still seems to be acting weird with the SoC of the battery. I currently have it connected through 485, and WOW.

I have attached some screenshots of my dashboard showing everything working . Still lots to mess around with, but this is a good start!

OmniVolt_8kw_SRNE_Modbus_Reference.docx

Thank you all, we managed to change the IC5 circled with red on the attached photo, it is related to the EPROM. Now it is working well and settings are remaining...
Am forever grateful to @HennieL and @Sidewinder be blessed...

Kuodos to Esener. It's the first Battery Spec that I've seen that actually specifies what BMS is inside the Battery.!

Solar Assistant has it's place, but detail multi battery analysis is not one of them. They can give you individual battery SOC's, temps, volts etc, but struggles to give detail. One of the most important metric's is the individual cell voltages, as well as the delta cell voltage per battery.
I, like @-cK- , use the Home Assistant method, so I can observe my batteries.
Cell voltages like this:

This way, you can actually "see" when a cell sag's/lag's during a charge/discharge cycle.

Because this graph tells me when the max. was achieved, I can at least attempt to retrace to see if anything extra ordinary has triggered such an occurrence.

You will need to determine what BMS the batteries are using and then look into a third party option to access that BMS data.
EG. My batteries uses the Pace BMS and I have an addon in Home Assistant that can pull the Pace BMS data from the batteries using an ESP32 bridge to the master battery's RS232 port.

@DAVID-EC
The answer lies in your requirements.
Pro's:
Like @zsde says, if reliability is a must e.g. people in house requiring life-support equipment, then go parallel.
Parallel is a good option, if you have run out of (mostly) north facing roof, and only have East/West left, then you score 2 extra MPPT's to add to the original 2.
Less cost. One 5kW + installation is probably going to be a lot cheaper than flogging the 5kW and getting a new 10kW.
Cons:
Parallel is always more complex to install.
More costly. Wiring etc. And you would need to add more batteries, depending on the reason for upgrade.
From what I've seen parallel installation don't behave exactly the same as a single unit.
For standard household installations I would go with a single, bigger Inverter.
I don't think your older model will not be compatible with the newer 5kW models, just make sure they are on the same firmware level before you upgrade.
If overloading was you main issue, then be careful if you go the single route. A 8kw SS can only sustain 128A (6.4kW) from DC (batteries) at night with loadshedding.
So if you requirement is more than that, rather go for the next up model, e.g. 10kW.

I will probably want to monitor production, etc. I heard that the Deye Cloud is better than the ap they had before.

I agree that redundancy is good, especially if one plans to go fully off-grid.
Something else to consider: The "self consumption" or "idle power" of two smaller units (say 80W per inverter on the 5kW Sunsynk) vs one larger unit (say 100W for the 8kW Sunsynk). This 1.4kWh per day wastage is not significant, but will be more important for someone living in an area of less PV power (such as Cape Town) and/or with smaller battery capacity.

@DAVID-EC
The answer lies in your requirements.
Pro's:
Like @zsde says, if reliability is a must e.g. people in house requiring life-support equipment, then go parallel.
Parallel is a good option, if you have run out of (mostly) north facing roof, and only have East/West left, then you score 2 extra MPPT's to add to the original 2.
Less cost. One 5kW + installation is probably going to be a lot cheaper than flogging the 5kW and getting a new 10kW.
Cons:
Parallel is always more complex to install.
More costly. Wiring etc. And you would need to add more batteries, depending on the reason for upgrade.
From what I've seen parallel installation don't behave exactly the same as a single unit.
For standard household installations I would go with a single, bigger Inverter.
I don't think your older model will not be compatible with the newer 5kW models, just make sure they are on the same firmware level before you upgrade.
If overloading was you main issue, then be careful if you go the single route. A 8kw SS can only sustain 128A (6.4kW) from DC (batteries) at night with loadshedding.
So if you requirement is more than that, rather go for the next up model, e.g. 10kW.

@SRTosen ,
In @Steve87 's port 3 above, he specifies how to "talk" to a FW 10/8. You can't use PBMSTools, as only the FW eTower has a Pace BMS.

@King_M ,
If your inverter can handle it, then I would add a few more panels to better cover the winter periods.
You can also just replace your 4kW element with a 3 or even 2kW one to better use your PV.

I think you don't need an additional MPPT. Connect the west roof panels in parallel with the east roof panels. This will not overload the MPPT since the east and the west panels will never deliver full power at the same time. I have such a situation and write from experience. Condition is however that east and west panels are of the same type (same number of cells).

Not going to get much response with this attitude - sorry, that's just an opinion 😁 Keeping quiet now...

@King_M ,
If your inverter can handle it, then I would add a few more panels to better cover the winter periods.
You can also just replace your 4kW element with a 3 or even 2kW one to better use your PV.

Awesome feedback, thanks @Sidewinder
Looks like my best option is to bite the bullet and get a professional to sort it out.
Can't beleive I ever got a CoC for this system. Must have been a back handed deal with the installer.

@mocodoLet me give this a bit of a shot....but just remember, treat a comments, not as gospel.
I'm not an Electrician, just an engineer with a bit of OCD, and these are some thing you may need to pay attention to:
1) Split AC & DC ...shouldn't run in the same conduit.
2) Conduit / trunking for DC should preferably be made of metal.
3) I believe from end last year, new SANS regulation specifies even split conduit for PV wiring. TBC.
4) Labelling....lots of it. I see no labelling (unless it is on the Inverter cover), but even inside the new DB's, every item needs to be labelled. The next guy that owns/going to work on it doesn't need to figure out what is where.
5) Warning Signs..Lot's of it, especially on the other (main & sub) DB's in the house.
6) You didn't specify if you are adding a master battery or just adding another slave. If slave, add a disconnect for that battery, and a master disconnect for all batteries. Yes it's a schlepp, but it does make maintenance easier when the time comes (much later). Alternative, you need to ensure that the fuse in the current disconnect is upgraded to handle the increase amperage. (only for adding a slave battery)
General:
1) If possible, get the comms cable sorted between Inverter and battery. Just make life a bit easier with knowing a bit more of what is going on your system.
2) As already mentioned, Earth/Neutral bond, if applicable to your grid supplier.
3) What's with the yellow & blue wires going to the Aux port? Try and keep all types of AC wiring the same. Running out of Red wire is a lame excuse.
4) The wires to the load port looks very thin to me. You should try and route the 3 AC port directly down to the trunking, one set of wires in each flex conduit. Try and find another way to route your CT coil. Maybe rather use one of the empty ports behind the PV ones. I used one of the 3 comms ports (behind each other) next to the big battery port.
5) The plug for the Prepaid. Where is the RCD and CB for that.?
6) If you Inverter is going to work very hard (as most 5kW's do)...then make provision for fans, either at the bottom or on top to push/pull the hot air out.
7) In Change Over DB: From rhs. in position 3 & 4. Look like the have a LED illuminated of sorts. If it is the Grid and Inverter "Live" indicators, then good.
8) Same for position 3 & 4 from lhs, those looks like type 2 SPD's. Good if so. (may just be a reflection, like on your PV DB).

@mocodoLet me give this a bit of a shot....but just remember, treat a comments, not as gospel.
I'm not an Electrician, just an engineer with a bit of OCD, and these are some thing you may need to pay attention to:
1) Split AC & DC ...shouldn't run in the same conduit.
2) Conduit / trunking for DC should preferably be made of metal.
3) I believe from end last year, new SANS regulation specifies even split conduit for PV wiring. TBC.
4) Labelling....lots of it. I see no labelling (unless it is on the Inverter cover), but even inside the new DB's, every item needs to be labelled. The next guy that owns/going to work on it doesn't need to figure out what is where.
5) Warning Signs..Lot's of it, especially on the other (main & sub) DB's in the house.
6) You didn't specify if you are adding a master battery or just adding another slave. If slave, add a disconnect for that battery, and a master disconnect for all batteries. Yes it's a schlepp, but it does make maintenance easier when the time comes (much later). Alternative, you need to ensure that the fuse in the current disconnect is upgraded to handle the increase amperage. (only for adding a slave battery)
General:
1) If possible, get the comms cable sorted between Inverter and battery. Just make life a bit easier with knowing a bit more of what is going on your system.
2) As already mentioned, Earth/Neutral bond, if applicable to your grid supplier.
3) What's with the yellow & blue wires going to the Aux port? Try and keep all types of AC wiring the same. Running out of Red wire is a lame excuse.
4) The wires to the load port looks very thin to me. You should try and route the 3 AC port directly down to the trunking, one set of wires in each flex conduit. Try and find another way to route your CT coil. Maybe rather use one of the empty ports behind the PV ones. I used one of the 3 comms ports (behind each other) next to the big battery port.
5) The plug for the Prepaid. Where is the RCD and CB for that.?
6) If you Inverter is going to work very hard (as most 5kW's do)...then make provision for fans, either at the bottom or on top to push/pull the hot air out.
7) In Change Over DB: From rhs. in position 3 & 4. Look like the have a LED illuminated of sorts. If it is the Grid and Inverter "Live" indicators, then good.
8) Same for position 3 & 4 from lhs, those looks like type 2 SPD's. Good if so. (may just be a reflection, like on your PV DB).

Thank you for the feedback and nice upgrade 👌👏
Just for discussion sake and for others reading the thread it’s worth clarifying something about MPPT configuration on the 8kW vs 10kW units.
On the Sunsynk 8kW Hybrid Inverter, you have 2 MPPTs with 2 inputs per tracker. If configured correctly, it could have been arranged as:
MPPT1:
• 9 × 550W North
• 9 × 550W West
MPPT2:
• 7 × 610W East
Since the North and West strings use identical panels and identical string lengths (9 in series), their Vmp is the same. When paralleled on one MPPT, the tracker operates at a common voltage and the string receiving more irradiance simply contributes more current. In this case, there is no voltage mismatch penalty.
The East string (7 × 610W) would remain independently tracked on MPPT2.
So from a pure solar harvesting perspective, the 8kW unit could have achieved essentially the same DC efficiency if wired optimally.
That said, the upgrade to the Sunsynk 10kW Hybrid Inverter does bring advantages:
True independent tracking per orientation
Higher AC output headroom (10kW vs 8kW)
More flexibility for future expansion
Better winter production due to the additional East capacity
Your winter benefit will mainly come from the added 7 × 610W East array and the broader production curve not strictly from having a third MPPT.
Overall, it’s a strong system either way 👍

@chrisc ,
Your first line of the timer config does not make sense, and so does the rest of the lines.
As far as the inverter is concerned, you've only defined 2 time periods:
1) 15:00 to 18:00 and
2) 18:00 to 15:00 (which is the next day)
You should devise your 6 lines into periods that would matter to your own circumstances. Best is to start at 1) 00:00 to 05:00 and specify the minimum percentage you want to allow the Battery to go down to (e.g. 50%)before the grid kicks in. If you tick the Grid box, it means you want to allow the Grid to also charge the battery, should is go below the set %. Gen is generally not ticked, unless you actually have a Genny connected to the Gen port and an auto-start feature connected as well.
2) 05:00 to 08:00 40% Used typically to power a geyser for that warm early morning shower, to use only 10% of the battery, and then switch to grid to power the house. (Assumption here is that your whole house is on essentials. If not (i.e. Geyser on non-essentials), then it will use Grid to power it, and reduce the grid consumption as the sun rises.(CT coil installed in the correct location. If you make the % higher that the previous timeslot, e.g. 60%, then it will only use grid during that time if the sun is not up yet. These assume that your SOC% is lower then specifies, else it will continue to draw from Battery as usual.
3) 08:00 to 13:00 70% This setting is to sure your get some minimum energy back into the battery. The idea is to hopefully get to a full battery by the time the sun is close to setting.
4) 13:00 to 17:00 95% Making sure the battery is just about full.
5) 17:00 to 20:00 80% Very little PV power so start using the battery, but limit it to 80%, so you have enough to go through the rest of the night.
6) 20:00 to 00:00 60% Use more battery power till midnight and the cycle starts again.
You need to adjust each timeslots start and end to suit your own requirement, as well as the SOC%, as the numbers above are just examples.
Don't be afraid to experiment, it normally take quite a few iteration to get the inverter to behave correctly.
Even so, one should adjust these numbers and times to suit, for each season, and also in future when TOU tariffs kicks in.

@mocodo ,
The answer is as always: It depends on your needs!
Owning a very expensive Inverter & even more expensive battery should warrant a decent monitoring system for each component.
Manufactures' efforts (Apps) are basic at best.
Solar Assistant (SA) goes a long way, but from what I can see, both Dyness & Deye batteries mentioned cannot be monitored with SA. If Dyness is mentioned specifically:
Connecting a Dyness / Mecer battery
If an inverter is already reading the Dyness battery, then SolarAssistant can not read the battery at the same time. The battery unfortunetely doesn't support being read from multiple devices at the same time. Set SolarAssistant to "Use inverter values".
This is because once you set up the battery for CAN (to inverter) via dip switches, the RS485 port can only be used a Link port to slave batteries.
Would be nice if some clever ouks can find a way to "fix" this shortcoming.
The Deye battery has a similar port layout to the Dyness (1 x CAN & 2 x RS485), and the Deye battery is not yet mentioned in the SA documentation. Feel free to update this, if anyone know more.
Even so, SA's lack of flexibility and crucial battery information e.g. cell voltages, does not give one the info to know what exactly goes on in a battery, specially during a 24h "charge & discharge" cycle, never mind over 10 years, as these batteries are supposed to last till then. SOH is another metric that is missing in SA.
So, in conclusion, if you never intend to know what goes on in your battery, any of them will do, get the one with the most "bang for buck".
Else get something that you know one will be able to monitor (look for an RS232 port or and additional RS485 port)

@Turbulance ,
Maybe read up on this thread https://powerforum.co.za/topic/515-solar-geysers-guide-me/#comment-6296
In it is an attachment of what my WH system looks like.
Basically a 200 + 150 Geyser in SERIES with a HP and tubes. Gives you plenty of hot water for early morning showers, and doesn't burden my Solar system when not used (only 2 ppl in the house atm.) Scale = 1 faint line = 500W

@Sidewinder @Demo
I see the links are working again today, and the prices are still the same. You can use the links in my first post or just find the items on the website!
Edit: Also I have confirmation that the units are being delivered. The guy from carbonite.co.za that ordered the 3kW unit has received his unit today!

@sam.tech96 ,
I use the Open-Meteo Solar Forecast Integration available in HACS for my forecasting, on which I base automations on to determine how low to take my batteries down in the morning, based on this forecast. I'd say about 90% accurate.