HennieL

How are the batteries connected to the inverter - through a busbar, or with cable going from one battery to the next? (thinking that if one cable is longer than the others it could result in under-charging...) Also, were these batteries all fully charged/balanced individually before connecting them to the inverter? (if not, then it is possible that the less charged battery will progressively become even less charged, as the inverter could stop the charging when the first battery signals that it is fully charged...) I'm not sure if the Deye's software is similar to that of the Sunsynk (I do believe it is...), but if it is then you could download *some* battery data (more than displayed on the inverter screen or software. I discuss the process here: https://powerforum.co.za/topic/34104-finding-and-understanding-the-sunsynk-operation-data/ I can unfortunately not advise directly, as I do not know this battery - but I hope that someone can help you.

According to my Sunsynk installation manual the CT coil's arrow must point to the inverter - see screenshot below: I'm not a sparky, but given that your inverter + PV panels should feed your non-essentials while the sun is shining, is it correct to "feed back" to your non-essentials from the "output" side of the earth leakage, as shown in your diagram?

That's shocking to hear, and they want us to trust them... Seeing that Solar Deity does not want to answer my simple questions regarding other "agents" for Pylontech, I did some digging via Google AI: "Pylontech operates through a shared agency network in South Africa, meaning they do not use a single exclusive importer. Instead, they distribute their products through a select group of officially appointed distributors and service agents. The primary official channels managing Pylontech imports, distribution, and official support in the country include: 1. Primary Appointed Distributors (Importers) The bulk of official Pylontech stock enters South Africa through a few large-scale solar and electrical wholesalers who handle direct import and distribution: SegenSolar: One of the most prominent official distributors in SA, operating multiple distribution offices and service centers across the West Rand, East Rand, Cape Town, Durban, and Bloemfontein. CNBM (China National Building Material Group): A massive global entity that imports and distributes Pylontech equipment alongside other tier-1 green energy solutions in South Africa. ACDC Dynamics: Operates as a major official reseller and distributor, leveraging its massive nationwide electrical supply network to distribute Pylontech residential and industrial battery solutions. Current Automation: Another major technical distributor that officially stocks and supports the Pylontech range through main hubs in Johannesburg, Cape Town, and Durban. 2. Appointed Service Agents Because Pylontech does not have a direct brick-and-mortar corporate footprint for public walks-ins in South Africa, they delegate technical repairs and warranty assessments to specialized domestic partners: Solar Deity: Officially designated as the appointed Pylontech Service Center for South Africa. Based in Gauteng, they handle physical diagnostics, technical support, and component repairs for units in and out of warranty. 3.Crucial Warranty Note If you are dealing with a faulty battery, Pylontech's corporate rule dictates that warranty claims must follow the exact supply chain of purchase. For example, Segen Solar will generally only process and approve a warranty claim if the serial number proves the unit was originally supplied out of their specific warehouse." I also note that Pylontech has a very low Trust index (only 2.2) and more importantly, a -100NPS (likelihood of being recommended)

These are nice words, but they are just words... I have never heard of your company, so personally there is no "continued trust" from my side - in my book, trust must be EARNED. Given that you have not answered my simple questions posted above, you have lost any "trust" from me that a fancy certificate (that could have been drawn by anyone...) might have generated. As for your goal to "reaffirm your confidence in Pylontech", what is wrong with Pylontech themselves? Don't they have any executives with enough backbone to admit that they screwed up, and that they will now change their ways and ensure that their representative(s??) in South Africa will from now on treat their customers better than what was the general case in the past? To be frank, I don't envy you trying to put right what others before you screwed up - but you won't be successful until you can convince the South African end users that your actions earn the trust that you would like to have... and that starts by being totally honest in your answers to questions asked in good faith. I still want to know if Pylontech have any other appointed "Partners" in South Africa, or are you now the sole South African agent and legal representative of Pylontech for sales and service?

The info is spread around a bit... "vpv1, ipv1, vpv2, ipv2, vpv3, ipv3, vpv4 and ipv4" are in columns AU - BC, and "ppv1 to ppv3" (why no ppv4...) are in columns CL - CN in the 2026 version of their downloadable daily spreadsheets. Sometime in 2025 they added an additional column or two, and thus the earlier versions' pv data might be in different columns. Hope this helps...

Hopefully you are still getting your coffee 😉 😄

Can you please confirm if Solar Deity is the sole (only) agent for Pylontech in South Africa, or are there other agents also importing and/or supplying Pylontech products into the South Africa market (Supplying, not just servicing...)?

Thanks for the heads-up everyone. Even though it might not resolve your problems, take heart that your warnings are heard - I for one will certainly not buy a Pylontech battery, or do business with their South African importers... Stand strong - perhaps a class action might convince them to honor their warranty rather than hide behind small print...

Just to confirm: The contour plot in the post above is for annual optimum - the winter value would move the 100% dot to the 50-60 degree region.

Hi @Kory Can you please provide the slope angle and the azimuth (degrees offset from north) for both your existing strings, and for the garage/granny flat roof. It might be worth looking into having a string of panels installed for optimum winter conditions (and not for best "year-round" generation). This would mean that the panels would have to be installed at a much steeper vertical angle than for the "year-round" optimum, and for Cape Town that would be about 55 degrees from horizontal. One would have to run a PVGIS simulation to determine the exact figure, but I would be surprised if it is far off from 55 degrees... Regarding the optimum azimuth, according to research by W.G. le Roux of the University of Pretoria's Department of Mechanical and Aeronautical Engineering, the optimum azimuth is not necessarily at true north, but could in fact be offset a few degrees east or west, depending where in South Africa the site is located - and for Cape Town (actually Stellenbosch in his research) the ideal azimuth for annual yield is approximately 5 degrees west of true north. For a winter-optimized array, the westward bias may actually become slightly more pronounced because: Winter frontal weather in the Cape often clears from west to east after a cold front passes. Morning cloud and mist are generally more common than afternoon cloud during many winter periods. The low winter sun makes the system more sensitive to weather asymmetries than during summer. Here's the calculated azimuth projection for Stellenbosch: Even though I'm from Bloemfontein, I trust this is of some value.

@Elro You should also make sure that the battery connection cables going to the busbars are the same length and diameter (cross-sectional area, actually) for both sets of batteries. Even though cable resistance is normally very low, the high current flowing when charging and/or discharging the batteries can result in the set of batteries with the longest cables being charged slightly less, and thus develop an imbalance with respect to the other set. Over time this can get gradually worse, and could lead to damage to your batteries in the long run (especially if they are lithium ion batteries...).

If I may suggest: plan from the start to buy a good quality inverter, and larger than what you think you need. I know, cost always come into the equation, but so does having to upgrade again in a year or two at additional costs. A solar power system should be designed to provide for your (expanding) needs for at least 10 years, in my opinion. I am fortunate that I was given this advice before I upgraded from my 2.2kW 24V inverter 21 months ago - I had considered a 5kW system to be "more than I needed" at the time, but was convinced to rather upgrade to a 12kW single-phase inverter, with 8kWh PV panels and 20kWh 52V LiFePO4 batteries. I have been practically off-grid for the last 6 months, with the grid feed to the inverter switched off at the DB board. I am able to run my full house, including a 200l geyser and a large oven without any grid input, only switching the grid on on Sundays for a few hours to keep the utility meter "ticking over", and if rain & heavy clouds lasts for more than 48 hours.

I agree with @Denns for the following reasons: Unless the panels are installed at exactly the optimum angle (and that changes daily throughout the year...), it is very unlikely that the panels will produce their rated current/power. Unless one is exporting power to the grid, it is unlikely that the demand will be at the 100% power rating in any case - and one can simply limit the PV input power by slightly limiting the power demand during the peak solar period (12:00 - 14:00) Even if the panels do produce their rated power, the inverter will simply limit the power to the maximum that it can handle. This will produce extra heat, though, and one should ensure that the inverter is installed where it can dissipate heat properly - but that is good practice in any case... It is common practice to install slightly more PV than the inverter's power rating, as long as the VOC limit is respected, but it is also just common sense to not go overboard with this.

I just had to laugh at your description, picturing you slipping down the roof with a very sore backside - apologies for laughing, but you do paint a vivid picture... glad you managed to stop the splat from happening... Best of luck with the upgrade - just ask on the Forum before you buy, hopefully the combined wisdom on the forum can save you from making another expensive mistake.

The "spec" label does not tell the full story. Look in the actual specifications sheet for your PV panels (download it from the internet if you do not have it) for something called "Temperature coefficient (VOC) or something in that line. You should see a small % value - something like (0.30%/°C). You must also know the Open Circuit (VOC) voltage (52.27V according to the lable that you provided). Here's an example of then calculating the maximum number of panels per serial string: If: Panel Voc = 52.27 V at STC (i.e. at 25°C) (from your label) βVoc = −0.30%/°C (assumed) Lowest expected temperature = −5°C Then: Temperature difference = −30°C Voc increase = -0.3% x -30 = 9% So the panel Voc could reach approximately: 52.27 × 1.09 = 57.0 V (per panel) Your inverter states a maximum PV Array open circuit voltage of 500V. So: Maximum number of solar panels = 500/57.0 = 8.77 panels... so the maximum safe number of panels per string would be 8 (don't round the 8.77 up to 9...) Please note that this example is based on some assumptions - you must get the accurate figures and do your own calculations!

I agree - after inputting the expected solar harvest (kWh/kWp), I get close to the same payback period (6.1 years) that my manual ROI calculation gives (I'm currently standing on 30% of total cost recovered in 1.75 years, extrapolated to 100% = 5.8 years...) - this really is well done 👏

OK, I quickly ran the numbers via Open-Meteo (A really great site for all things weather related...) using a 20 degree west of north azimuth and a roof/PV panels slope of 15 degrees, and with my 14 panels this gives a solar harvest loss of some 2.9kWh at peak production - see images below (Figures are historic values for Tuesday 9 June 2026) At my actual 27 degree slope and facing true north (-180 degrees): At an assumed slope angle of 15 degrees and facing 20 degrees west of true north:

Not quite - unless I tell you my actual panel tilt angle and azimuth, someone (PVGIS?) must make an assumption by using the optimum values - and unfortunately there are very few roofs with slopes constructed at exactly the correct angle for optimum solar yield (there wasn't even such a term when my old house was built in the early 1970s...) Also, thanks to clever town planners, many roads do not run directly east-west or north-south, and many houses are built at less than optimum azimuth angles as well. I accept that your town + area location is probably close enough though, but someone placing panels on a roof in Bloemfontein that only has a slope of 10 degrees from horisontal will have a significant loss in solar harvest potential, compared to a roof of (say) 30 degrees - and the same goes for azimuth angle...

One more thing - Why do you not include the "Panel ageing" cost in your off-grid calculations? Panels will age and need replacement whether you are using grid power or not... Also, I think the "Panel aging" cost is way to high. My panels' purchase cost was about 16% of the total investment, and according to your calculator replacing my 14 panels will cost 114% of my total initial investment - that surely cannot be correct.

@TheOracle This is turning into the best PV cost calculator on the web - well done. I think one further positive adjustment could be made by having the user input his approximate co-ordinates (latitude and longitude), azimuth (direction that the panels are facing) and panel tilt angle. These three variables will define the actual Global Tilted Radiation GTI value that the solar panels can produce, and will thus bring the solar harvest calculation still closer to actual.

Ja Swaer - cleaning panels beats mowing the lawn hands down 😁

Nice, but there is one serious flaw in your calculations - TAX. Your "Interest you gave up" will be taxed at (say) 35% per year, whilst your saving for not paying for electricity is totally tax free. Run the numbers again with this taken into account and your investment will look much better.

VERY good prices... wish I has space for another 36 panels 🫠 Anyone in Bloemfontein or surrounds that want to club in and share a pallet - I will take 8-10...

Mine are similar, but because I believe that one should not deep discharge any battery my percentages are just higher than yours. 01:00 - 08:00 : 50% 08:00 - 12:00 : 60% 12:00 - 15:00 : 70% 15:00 - 17:00 : 100% 17:00 - 20:00 : 90% 20:00 - 01:00 : 60% Of course, since going "virtually off-grid" (grid normally switched off at the DB, only switching it on when conditions are such that my panels can't cope), These settings do not mean anything as there is no grid to maintain the percentages...

Perhaps you should state where you are located, and give an idea of where & how the batteries and inverter will be located (garage, store room 50m away from the house, etc...)