GreenFields

Can we start with a description of how much hot water you use and when? If you're using 25-30kWh per day on the geyser, even before the solar, that suggests that you are emptying the geyser out and re-heating it about 5 times per day. Just speculating, it could be for example for 5 people each taking a full bath or long shower during the day, and most likely when the sun isn't up, and a usage pattern like that could explain why solar water heating (any type) might not be giving you the savings you were expecting. Again, just speculation. Beyond that, could you confirm the amount of solar panels you've got connected, what the timer settings are for turning the geyser on and off, and how this corresponds to the inverter's operating settings, work mode settings. Other than that, can you confirm whether maybe your inverter's work mode settings are set up for solar export to the grid, and whether a pre-paid (??) meter is registering your exportation as consumption. Maybe post pics of the inverter screens. I'm assuming your installer has put the CT coil in correctly, but should be checked anyway.

Not 10. You'd be at very high risk of blowing the MPPT. Even 9 per side could be pushing it. Simplest is 8 of the same on the other solar input. If you really want the power of the 2 extra panels, then maybe consider 8 of a different panel type. Something like a 500W panel that produces power at a higher current like maybe around 12-13A.

I'm assuming you won't be setting up to export battery power to the grid, only solar. And that you've got a 60A main circuit breaker. If not, the values below will change. Simplest thumbsuck would be under the Battery Settings to set the battery charge current limit to around 65A. And you almost don't need to worry bout the export limit, since you've got only 2660W of panels connected, but it should be possible under the grid settings, to find a grid sell limit setting, which you could set to 3500W for in case you intend to add panels. In principle.

What batteries are you using and how many per inverter? It could be a limitation set by the battery's BMS.

Personally I'd keep the maintenance under control of the body corporate. Something maybe like designating roof sections as exclusive use areas and charging levies that cover the costs. Or else installing the solar panels exclusively by the body corporate, and selling power to the grid. But not leave it up to the individual owners to take responsibility for maintaining the common property.

Check if it's referring to the password on the label that's on the side of the dongle itself.

Thanks, but relax, I'm easy. More bemused than offended. Look, if one follows the NRS 097 guideline, then your 3-phase 100A supply should be capped at 17kW export capability, which is around 25% of the 69kW maximum power on that line. This is already being exceeded with the existing 30kW installed. Going out on a limb and saying this is clearly not the average size home supply. You've obviously already calculated that you can add another 30kW to get closer to the peak power rating of the supply line, you'll have around 86% of peak capacity connected. Just bear in mind that you can probably just carry 23kW per phase, so you may have to re-consider onto which phase you install which additional inverter(s). Honestly I don't know whether CoCT has dispensed with NRS 097 just because they want to buy every last kWh they can. Maybe you should ask them that in writing before proceeding. Lastly, I don't deal in precise maths, only in rough 2c's worth, some high-level thumbsucks, a couple of estimates, and I'll leave it to you and your installer to sort out the details about installing that much power in your home with CoCT.

Maybe start with confirming what exactly is your grid supply size, or what size circuit breaker have you got? Probably not a single-phase 60A circuit breaker. 80A? 3-phase? Rating per phase? Is it typical of the average household? Your breaker might not care which way the power flows, but it might care if you exceed its rated current.

It's the other way around - @macafrican is saying that at the Eskom customers WITHOUT solar are currently paying on behalf of the people that DO have solar. The old tariff structures were fine when nobody was using solar, but now more and more solar is buggering up the assumptions that are underlying the old billing. The point is, the true cost is made up of a fixed rate for the infrastructure before you've even used a single unit, and a variable rate for burning coal to produce power. This is what is charged to your municipality by Eskom. However, the municipality in turn was always charging the individual households NO fixed charges, and everyone the same fee per unit, probably for simplicity. If everybody keeps buying from Eskom, the billing models make sense. But when Solar users are buying for example just 10 units per month, then they are not buying enough units anymore to cover the fixed charges of maintaining the grid. That cost then falls to the remaining people that are still buying around 600 or whatever units. That's the less bad scenario when at least folks are using batteries. A further problem, on top of that, and that's the case here, there's the issue that it costs Eskom differently at different times of the day to generate power, low-cost during the night and most of the day when generating from coal, and a much higher cost during peak time when they have to run expensive gas and diesel peaker plants. Let's say - just making up the numbers for illustration but it's not far off - that it costs 80c per unit to produce power at noon, and R8,00 per unit to produce power at 6pm - as long as people are paying around R2.68-R3.71 all around the clock, it sort of works out. You "overpay" at noon, and you "underpay" at 6pm but on average it's fair. Now what happens with solar is that people are not paying anything during the day anymore, but at night they want to buy the most expensive power at below the cost of generation. The utility can only lose like that. Not just losing out on sales, but actively losing money that other customers must somehow cough up for. And the solar user is either oblivious, or doesn't care, and gets indignant about it, as if buying solar power gives him a right to do what he wants when he wants no matter the costs to others. Just in principle, the only fair way is to start passing on the billing to the end user in the same way as the municipality gets billed by Eskom. A fixed rate, combined with a time-of-use billing, including also a time-appropriate rate for selling into the grid. At appropriate corruption-free price levels, whatever that may be. And it does change the economics around choosing the right solar system if you're buying new, and it screws up the assumptions you may have had if you've already bought.

I wasn't planning to reply to this topic again, but the article below is touching on the same topic. Basically Eskom is saying solar users can't get away with freeloading, ie. can't be subsidized by the paying customers for their connection to the grid. One can try to blame politics or corruption, and I'm certainly not saying I condone any such reasons, but I'm seeing a simple economic rationale behind it. Nobody is forced to use Eskom, and anyone who doesn't like the proposed R1000 monthly charge is surely free to provide his own infrastructure, which would be in the ballpark of R150K-R200K upfront for a roughly equivalent 12kW hybrid inverter kit. https://www.moneyweb.co.za/news/south-africa/eskom-tariff-structure-changes-here-are-the-winners-and-losers/

Could possibly be simulated by using the PV-on/off switch on the underside of the inverter (example Sunsynk/Deye) under exactly the wrong conditions.

If you go the low-frequency route, try looking for models from Victron, MLT, Microcare or SMA. Not an endorsement of any particular manufacturer.

It's normally calculated as 25% of the Notified Maximum Demand, where he'd have basically a 60A circuit breaker, which at 230V will have a notified peak output of 13.8kW. And 25% of that is 3.45KVA. Not sure how the 3-phase scenario fits in. Does he maybe have a limit of 3.45kVA per 60A phase? If you ever find out definitively technically why that limit is so, I'd love to know. There are some old threads if you search the forum with some thoughts of grid stability. Bear in mind if you're exporting full power, it's not impossible that a cloud comes over and the grid suddenly has to pick up the slack for whole neighbourhoods in short time. Extract from the NMBM SSEG doc reads: "As most domestic, commercial and small industrial LV supplies are fed from a shared LV feeder, the maximum individual generation will be limited to approximately 25 % of the customer’s NMD" In reality more folks these days are buying hybrid inverters in the 8-12kW range or more because of loadshedding. I wasn't even sure if these rules are still being applied. Last chats on the forum I heard just that the inverter's power rating should be lower than the grid power capacity.

Doesn't sound like a correctly laid-out installation. Best is probably just to work out the best configuration and fix it and have a happy customer. Petty would be to badmouth the other installer.

Most likely your Deye account is set to the time in Cairo, while your installer may have manually over-ridden it on the inverter and set the local time. Egypt uses daylight savings time that changes by 1 hr with the season, whereas GMT+2 Harare/Johannesburg is fixed. Maybe try to log in via the SolarMan web portal. I can't change mine, though, I only have a user account.

You are right. I guess no prizes then.

Just wanna say, I called it. Were there any prizes up for grabs? https://www.news24.com/news24/southafrica/news/joburgs-city-power-to-implement-load-reduction-to-protect-grid-from-total-collapse-20240608

Maybe one of the first signs that loadshedding is about to return after the elections? Reduction in power quality due to insufficient generation capacity to meet the winter demand? Or maybe just a localised issue with a "bent" cable? Either way, thanks, I'm going to re-set the Voltage parameters on my inverter. Found out last time that it reverted to default values when a new firmware was installed.

Just my 2c, going out on a limb again. To be checked. I seem to recall somewhere in a different thread you were speaking of multiple aircons to be used, maybe a 36000btu or whatever aircon by day, and 3x18000btu at night, but you had a 40A grid supply limit in the complex. Is this correct, is it the same house? Because given those figures, I wouldn't go for 3kW or so electrical elements on top of the other loads, whether it's running off PV, or even as backup elements to evacuated tubes, if you could most reasonably/sensibly/legally(?) only fit an inverter of up to a 8kW. If so, suggestion would be to look into a 3.6kW heat pump like the ITS model, but shop around anyway. Point is, it will consume less than 1kW by itself, and still generate effectively 3.6kW of heating capacity that you could connect to a geyser of up to 200l. I think in your hot climate with regularly higher ambient temps, and generally low usage of water, you could get away with a setup like this.

Do you have single-day graphs available for each time of year? Would be useful to know what time of day your loads are, and if there is any opportunity to shift more of your loads to be covered by solar during the day. But it looks like one battery will help you to make better use of your potential surplus solar power from around September to May. I'd do those two, ie. timers to shift loads to sunlight hours, then consider to get one more battery to use more of your solar resource at different times of day. Lastly you could consider more panels, but that's more useful for Winter and overcast days. For a normal average day you probably are okay. That's all a gut-feeling thumbsuck. Only makes sense to decide once you've considered daily loads and the time of day you run them.

Is this a new installation? The conditions to produce close to the peak power are usually mainly present during summer.

The inverter is specified to take up to 6500W of solar panels. The "cleanest" would be to add more of the same 505W panels as you have now and arrange it as 6 per MPPT. It is not necessary to balance the MPPT's. There are I suppose different views on whether you could/should exceed 6500W, or whether you could/should exceed 3250W per MPPT. Personally I stick to the dataplate on my own inverter, but others may differ. It's possible to add different panels, but ideally the voltage and more so the current specs should be a close match.

When the grid is gone, the time of use function settings will be disabled, and the inverter will simply switch over to the battery. There could be financial reasons why someone chooses to run from battery instead of grid. Like I'm doing it to avoid peak-time Eskom/utility rates.

Is this 4S2P on one MPPT, or did you connect 4S per MPPT? Do you have any graphs maybe showing the difference between those setup ideas? Just have this nagging question in my head of whether 4S2P on one MPPT would resolve the issue, since the MPPT Voltage should hopefully not drop below the shutdown Voltage in the morning when one of the strings gets early shade shortly after starting up.

From your description, nothing sounds wrong, this is just how it works. The inverter itself has a self-consumption to power its own inverter electronics, screen, fans, wi-fi, communications to the BMS, etc. If you are enabling the TOU function, you are essentially activating/controlling the use of the battery. The system is doing exactly what you're telling it to do, which is to run down the battery instead of the grid. If you don't want to use the battery, then either disable the TOU function, or keep the percentage at 100%, or limit the battery Power to 0 Watts on the TOU screen.