Kalahari Meerkat

it should make a difference, how noticeable, is tough to predict, if there is no partial shading on either of the strings, when they should be producing energy, it should be worthwhile, I'd say
the inverter should throttle the power back to what it is able to consume/charge the batteries
the more important one is the strings Voc, which should be ok, I think, just a hair under 50Voc per panel * 7 = 350Voc per string, which, I believe, the Sunsynk would be ok with, maybe double check this, I don't have a Sunsynk here anymore...

Yes it has two separate MPPTs
Yes, within limits of the MPPT, can't remember, but possibly around 20A Isc and 400Voc, check the manual/specifications for that inverter.
Maybe, but I'd check the Voc or the existing 7 and make 100% certain there is room for expansion, but personally, I wouldn't mess with the existing string, I assume it works and you already have nearly 4kWp solar on that MPPT, fill up the other one rather.
Yes, same or more current, but I'd suggest you leave the string as it is, rather...
should be fine as long as the Isc and Voc values of the string fall withing the MPPTs specifications...
I would think not, same manufacturer, just Sunsynk is a different label/Deye rebranded and sold under the Sunsynk name. But others may know more, as it is, I doubt that Sunsynk or Deye actually manufacture batteries, so yet again some other manufacurers items being rebranded...

Yes it has two separate MPPTs
Yes, within limits of the MPPT, can't remember, but possibly around 20A Isc and 400Voc, check the manual/specifications for that inverter.
Maybe, but I'd check the Voc or the existing 7 and make 100% certain there is room for expansion, but personally, I wouldn't mess with the existing string, I assume it works and you already have nearly 4kWp solar on that MPPT, fill up the other one rather.
Yes, same or more current, but I'd suggest you leave the string as it is, rather...
should be fine as long as the Isc and Voc values of the string fall withing the MPPTs specifications...
I would think not, same manufacturer, just Sunsynk is a different label/Deye rebranded and sold under the Sunsynk name. But others may know more, as it is, I doubt that Sunsynk or Deye actually manufacture batteries, so yet again some other manufacurers items being rebranded...

The CT is exactly what its real name says... a Current Transformer... basically it is a coil through which you run another single coil (just your live or neutral wire through the center of the CT), this then forms a transformer, where the current running through the single winding is providing a magnetic field to the multiple windings of the CT's coil, this, with the single winding becomes a actual transformer, but really not much power can flow, since probably a few thousand windings vs one, while not transfer much, but will provide some mV's of measurable Voltage which can be used to calculate the current flowing. The problem with most inverters is that if a high powered consumer device which is being powered by the inverter is switched off, the inverter needs to get rid of some energy fast, so as not to let the Voltage on its output rise rapidly and usually the easiest way is to feed the power to the input end... and thus the grid... at least that's the way it seems to me...

Ok, lots of off-topic postings, let me muddy the waters waters by throwing in my 5 zim-cents worth...
If all you need is more kW power from your inverter, but not more solar production options, then two 5kWatters are fine, but... looking into the future and maybe even now, where you may want to add more solar panels to produce more power, the 5kWatters are a bad idea, they are limiting the current on the PV inputs such, that quite a few panels that are available these days won't foot the bill and you may struggle to find panels that will work well with the Sunsynk/Deye 5kW inverters. The 8kWatters are a better option and looking at Solis should not be off the table either.

On a decent transformer, probably less than 4% at full power, but it would be an expensive affair, transformer to be mounted indoors, I'd say, or in a box, just outside the wall, where the DB is located... cooling is an issue, even with an oil cooled unit this could present problems...
Maybe another approach would be one of having a field mill or two on your property, this should give you a a fair indication of an imminent near or direct lightning strike, this in turn could be used to drop a contactor or two which disconnect from the commercial power side etc. for 30 seconds or a minute, until the field mill readings indicate things are ok again, this however in a thunderstorm, could disconnect from the commercial power side a few times during the storm, assuming of course the lightning discharges are fairly close to your field mills locations... I am still considering setting up such a solution here, would be pretty unique, I think and done right could prevent nearby strikes causing any induced power problems...

yes, well, there is no reason to throw everything at one MPPT... you could for instance consider doing 3 MPPT's, 2 X 250/100's (6S1P panels each, assuming the Voc fits) and one to suit the remaining 2 panels, there is more than one road that lead to Rome...
I also was of a similar feeling, specially since Victron was very expensive back in 2020/2021, but since their pricing has come down quite a bit and unlike your all in one outer-Mongolian units, are fairly EMI/RFI quiet, as opposed a lot of the all-in-ones/high frequency inverters.
Looking at just one MPPT does not make sense... lightning strike and the MPPT is gone... no panels will produce power, whereas if your panels are slightly spread out and running on 2 or more MPPTs, then you may at least still have some solar power being produced, if weather has struck...
Just because your 14 panels in a single string may fit the 450/200 (not sure, maybe its 7S2P), does not mean that this is the correct way to implement the solar power production side...
Here, FYI, I was running a 5k SunSynk, now I have 3 X Multiplus II 3000VA's in parallel and 2 X 250/100 MPPT's + 1 X 250/85 MPPT and a bunch of batteries... off Eksdom's infrastructure, of course.

DiY, I'd say, get some (16 or 32, depending on kWh wanted) 314Ah EVE cells, a 150A or larger JK BMS (or two, depending on the amount of batteries involved, normally 16cells per battery) and voilla, mine is compressed, but not enclosed, in the garage on a angled steel narrow structure, with ply wood as the base for the batteries to sit on... not planning on moving them, but if I must, then I will break down the batteries and move the cells individually to their new home...

I had issues using a cut-off saw on start up previously when the battery capacity wasn't looking too great here (old LA batteries...) anyway, the cutoff saw, once running, was no issue, the startup, though... anyway, what helped, was briefly pushing the power on, on the cut-off saw and then releasing it, half a second later, same procedure and rinse repeat 3 or 4 times and then usually the saw was up to speed and I could keep the power button depressed and no issues from the inverter/battery end...
You try the same with your lawnmower, tilt it up on it rear wheels, so the blades are no in contact with the grass, then pulse start it, like I did with my cut-off saw, if you are lucky, buy a lotto ticket you can get the lawnmower to run without tripping the inverter... this may not work for you, but worth a try anyway, I'd think...

If you cannot solder the surface mount resistor, you can try and get a leaded 1% tolerance 1/8W and solder that in, but with a fine soldering tip on a Weller or similar temperature controlled soldering Iron, you should be able to do this yourself, assuming you're not like me, needing serious magnification to see that the fly dirt is actually a SMD device...

If you cannot solder the surface mount resistor, you can try and get a leaded 1% tolerance 1/8W and solder that in, but with a fine soldering tip on a Weller or similar temperature controlled soldering Iron, you should be able to do this yourself, assuming you're not like me, needing serious magnification to see that the fly dirt is actually a SMD device...

DiY, I'd say, get some (16 or 32, depending on kWh wanted) 314Ah EVE cells, a 150A or larger JK BMS (or two, depending on the amount of batteries involved, normally 16cells per battery) and voilla, mine is compressed, but not enclosed, in the garage on a angled steel narrow structure, with ply wood as the base for the batteries to sit on... not planning on moving them, but if I must, then I will break down the batteries and move the cells individually to their new home...

Yes/No, if the wires haven't run hot up to now and started a fire and the sizing is correct, then they should not start melting in the conduit and cause a fire either, I would personally consider metal as well, but, pricing and is it really necessary? Back in the day, well into last century it was metal conduiting by default and PVC wasn't even available until, I'm guessing the '70's or early '80's, but nowadays, the default is PVC and that is it...
I'd be much more worried about lightning protection, which is more likely to cause the thatch roof to start smoking...

Ok, thanks @stefan44 , @Greglsh and @Stefan Cornelissen
@Greglsh , I'm off grid, so it hardly ever does what yours seems to do, unless some clouds come in after the batteries are full and we run off those for a while before the sun returns, but even if we're down to 92% SoC before sunset, at this stage the lowest morning SoC I've seen is probably 45%, so not too panicked about the lower SoC late afternoon, unless the next day is supposed to be cloudy, then I try and minimise the consumption overnight, I guess I need to get off my lazy butt and add the other 2 batteries, to have a combined 60kWh and thus no more panicking :-)
Ok @stefan44 on your settings... 30mV for balance to cell max voltage seems a bit skraal, meaning it won't get much chance to balance before things drop out of range, just looked at yesterdays charge, 3.400V by 12:00, 55V by 12:22, and effectively if that was my setting, probably not 20 minutes later cells would be 3.400V or less and thus end of balancing... ok this was on my worst battery and there was 26mv delta between the cells once 55V was reached...
I'll do some more homework, maybe can start balancing earlier, say 3.400V and then bring cell max voltage down to, maybe 3.480V so 55.68V for the pack...

I have 4 panels, not ideally located, lots of shade early morning and afternoon, but the voltage of those is around 150V, when unshaded...

see Voltage graph above...

and power produced above... around 9kWh for yesterday.
The power curve above really shows the shading....

I have 4 panels, not ideally located, lots of shade early morning and afternoon, but the voltage of those is around 150V, when unshaded...

see Voltage graph above...

and power produced above... around 9kWh for yesterday.
The power curve above really shows the shading....

I have 4 panels, not ideally located, lots of shade early morning and afternoon, but the voltage of those is around 150V, when unshaded...

see Voltage graph above...

and power produced above... around 9kWh for yesterday.
The power curve above really shows the shading....

Ok, thanks @stefan44 , @Greglsh and @Stefan Cornelissen
@Greglsh , I'm off grid, so it hardly ever does what yours seems to do, unless some clouds come in after the batteries are full and we run off those for a while before the sun returns, but even if we're down to 92% SoC before sunset, at this stage the lowest morning SoC I've seen is probably 45%, so not too panicked about the lower SoC late afternoon, unless the next day is supposed to be cloudy, then I try and minimise the consumption overnight, I guess I need to get off my lazy butt and add the other 2 batteries, to have a combined 60kWh and thus no more panicking :-)
Ok @stefan44 on your settings... 30mV for balance to cell max voltage seems a bit skraal, meaning it won't get much chance to balance before things drop out of range, just looked at yesterdays charge, 3.400V by 12:00, 55V by 12:22, and effectively if that was my setting, probably not 20 minutes later cells would be 3.400V or less and thus end of balancing... ok this was on my worst battery and there was 26mv delta between the cells once 55V was reached...
I'll do some more homework, maybe can start balancing earlier, say 3.400V and then bring cell max voltage down to, maybe 3.480V so 55.68V for the pack...

Ethernet is twisted pair cabling which is fairly resistant to interference since its differential voltages applied to the pairs, in other words, the voltage difference between the 2 wires making up a pair make up a signal, if external influence induces a voltage on this pair, both wires if the pair would have their voltages lifted or lowered by the same amount, which means the pairs signal should remain intact... temperature, if your cables really get hot, then they are likely undersized and you should consider replacing them with larger diameter cables.
Depending on the length of the ethernet run and whether its in a location where lightning may be an issue, I would consider going fibre. In your case it would mean you need to add a small switch that can take a SFP+ module or a media converter, which just takes a SFP+ module and has a normal ethernet port out and on the other side of the fibre link, you hopefully have a switch that can take a SFP+ module, else same scenario, depending on the distance of the ethernet run, fibre can work out cheaper and if lightning is an issue, infinitely safer.

I think you and them are drifting off topic, if their side consumes your purchased electricity, without you consuming it, then that is what let the meter run down and that it what they need to fix, for starters and I can't speak about letting the prepaid unit run out of funds, but there are plenty of people that do run out and then in the morning have to jump to buy more and I am not aware of any of them needing to call out Eishkom/CoCT or any other municipality to be able to recharge their prepaid unit and get the power on again... maybe your Cherry picker rocket scientists need to expand a bit about their garglings...

I think you and them are drifting off topic, if their side consumes your purchased electricity, without you consuming it, then that is what let the meter run down and that it what they need to fix, for starters and I can't speak about letting the prepaid unit run out of funds, but there are plenty of people that do run out and then in the morning have to jump to buy more and I am not aware of any of them needing to call out Eishkom/CoCT or any other municipality to be able to recharge their prepaid unit and get the power on again... maybe your Cherry picker rocket scientists need to expand a bit about their garglings...

this takes me back to the days of buying your 1st HiFi, do you buy separate components, or a music centre/all-in-one... separate components, was a better bet, in my eyes... as for solar side, separate components make things look more complex, but from a reliability perspective is, I believe also a better bet...

both B- including balancing B- wire to main negative
B1 onward to cells positive terminals (from the most negative cell onward), and B+ will join the last actually connected B-lead (probably B16 in a 16S battery)
P- is power source/load negative connection and + connection is to battery's positive end for source/load
If you don't have the switch, then a voltage of around 5V between P- and B- should wake up the BMS

Wrong... here we have 5kW inverter, 38kWh battery and 4.7kWp solar...
If you do not want to "manage" your energy usage, in other words, run the dishwasher during sunshine/solar production hours, for instance and don't care about serializing energy use, in other words, run into the kitchen, turn on the oven, the kettle and the microwave all at once, then yes, and I dare say, the 30kW inverter may not be enough, but if you have a brain, engage it before just blindly flipping switches, then, like us, you will just about never reach the 5kW limit of the inverter, we regularly peak up to 4kW, never for very long and have yet to trip the inverter due to drawing too much energy, because we're running too many high consumers at the same time...
Been off-grid since 2020 with an extension lead from the neighbour initially... proper off grid since 2023 and feeding the extension lead to the neighbour, who is now also off-grid.

messy but doable... ideally you should still have a mini DB on the output side of the inverter, though... Earth-Neutral bonding contactor/relay and GFI/EL switch and then a socket for whatever you want to power...