GreenFields

Yes, the batteries are rated 1C charge according to the spec sheets, to take 105A each, so then if you charge at 100A that the inverter can handle, they will will still be charging at around 50A each, ie. well within in the battery manufacturer's spec. Basically at a 0.5C rate. But I'd set the inverter charge rate to 80A as a balance between going easy on your system (batteries as well as inverter), and extracting useful performance. That's around 0.4C or 4kW charging power, in your setup, on a panel set of just over 5kW. Any less, like if you're using a 50A charge rate on the inverter, then you'd be negating a fair bit of the benefit of having that many panels in the first place.

This is very close to the type of setup I was referring to in a previous post. Sorry, have to repeat this: it's a great setup for someone who needs more autonomy from the grid. But if you've got low usage of 15-20kWh daily, and typically under 6kW of peak power, then you could cut this system basically in half, I guess for around half the price, and still have a system that will meet your power needs 95% of the time (okay, I'm making that number up, but you get the point), as long as you stay grid-connected. And if you then still want to go more off-grid, then the logical upgrade path will be to buy the other half of the system.

If you are keen on fitting panels to the South-West roof, even if it's sub-optimal, bear in mind that the 12kW inverter has got three MPPT's, which can also take parallel strings. You could therefore combine your orange and red strings onto the first MPPT, two six-strings in parallel, leaving an MPPT free for the South-West side. Maybe you might struggle to fit at least 4 of the 600W panels, but if you could say fit 4, but better 5 of the 450W panels to MPPT3 facing SW, that could plausibly work.

Or else go with a 6kW Solis hybrid at the start, with just one 15kWh battery and 8x600W panels on just one MPPT, and keep the non-essentials on the grid side but powered from the inverter too. That's for a more cost-effective more grid-tied start-up that you could scale up by doubling everything up. Even if you don't, it should already go a long way towards covering the 15-20kWh daily usage with 6kW peak usage on most days. Your usage is not actually that much that a smaller system couldn't handle most of it even if it's sometimes a squeeze. How often is the grid out in your area, though? I'd be leaning towards the 12kW inverter and doubling from the start if grid-independence is the main immediate concern.

Please don't delete the question, you never know if maybe someone else comes looking for the same answers in the future. I want to say, though, that not everyone necessarily has the same experience. I've had my flat plate split system now for nigh on 10 years, and my pump has never given in. The panel itself has had a 10-year warranty, so maybe I should start expecting hassles soon, but so far it's been plain sailing. The only gripe is that it is not as effective in Winter as in summer, but it still helps by reducing the amount of top-up heating needed.

The usual disclaimer: Layman's opinion, personal 2c worth, use at own risk, to be adapted for your own situation, get professional advice. On the first comment, that you are early risers, etc. I agree that people have their own routines, own usage patterns, and that the optimum solution in one case might not work or make sense for others. The idea of increasing the water temperature to 70 degrees might work for people who want to store as much heat energy as possible for evening baths & showers for the kids, but if you then have adults who want to freshen up with a morning shower, I'm not sure if that using the geyser as a battery is always a workable strategy. For those who need hot water first thing in the morning, there's this idea to run off battery, alternatively a heat pump could do that heating for the morning (and generally) more efficiently off battery and solar. Finally, what I'm doing, is running the geyser from the grid in the early morning, using a timer, while on an off-peak time-of-use tariff that's cheaper. Back to the battery, though, I'm wondering if the concern about "using up the battery" on low-grade non-essential tasks like water heating really... yes I'm going to say it ... holds water. Firstly, if you need hot water in the morning for the family to wash and go to work, school, etc. then that to me is essential and time-critical. Beyond a point you can't shift all loads to the day. Next, though, I'm wondering whether the cost of the battery is really such a big factor as it was before, from the point of view that the cost per kWh cycled in and out of the battery has come down dramatically. Just using this 15kWh battery as an example (and I'm sorry for harping on it, I'm not a spokesperson for it, I just like the concept on paper), then 80% cycling down times 6000 cycles gives a cost of around R0.40 per kWh. A third of what it used to be when I first bought. You can't run from the grid at that price. Okay, one should factor in the capacity loss and installation costs and go on full quotations, but say that it ups the cost to R0.80/kWh. You still can't buy power from Eskom at that price, so I'd say to let rip, run a 2kW or even a 3kW element, well within the 100A recommended discharge capacity of the battery, without a second thought, and start treating home battery power like a disposable. The fact that some of these big batteries are floor-mounted and come with trolley wheels, tells me it shouldn't be that hard to swap them out while running on grid in the interim.

For the loads you want to run and the money you're looking to spend, while staying on-grid, I'd suggest to consider going big from the outset with a 15kWh single battery as in the link below to Powerforum store. But if you shop around there could be more alternatives also not too far away in price. Not too long ago that was the price on a 5kWh battery. Power Forum Renewable Energy Store | By Powerforum.co.zaKNY-P51300 15.36kWh Floor-Type LiFePO4 BatteryLimited Stock on this Special Price 51.2V 300Ah (15.36kWh) floor-standing LiFePO4 energy storage battery – Model KNY-P51300 from KNYSE Energy (part of the reputable Chilwee Group).This is a solid, no

Just a minor correction/comment. The OP is enquiring about pairing a Sunsynk inverter to a Dyness battery (not Deye), which is an independent battery brand with a wide compatibility to various inverters on the market. I have a suspicion, I don't actually know in black and white, but the OP could check that battery's compatibility list for the Sunsynk or maybe even the Deye brand to be sure.

From the heat that the inverter itself generates, maybe (thumbsuck) as much heat as from a 60W incandescent light bulb or a candle, I'd say the logical thing is that air above the inverter should be hotter than below, since that hot air inevitably will be rising upwards. What this thread is questioning, is whether you should position the fans to work with the natural rising airflow, or against it.

You don't seem to need it for now, but I'd run this system through the Winter to see how deep you need to discharge during longer colder nights. If you're planning to add loads like more heaters or aircons, or the tumble drier, or if you need to heat up your geyser from colder overnight temperatures, etc. then the extra batteries could come in handy.

Short answer is: "Yes" it can, and there are options to choose from. The below links are just two examples of 8kW inverters in the Powerforum Store, but there are certainly more you could research or ask questions on. Power Forum Renewable Energy Store | By Powerforum.co.zaSolis S6 Pro 8kW Advanced Hybrid InverterShop highly efficient Solis S6 Pro 8kW Advanced Hybrid Inverter that allows the user to hit those ‘parity’ targets by managing power coming from multiple sources such as solar. Request a Quote now!Power Forum Renewable Energy Store | By Powerforum.co.zaDeye: 8Kw Single Phase Hybrid InverterDescription Max Efficiency of 97.6% 2 MPPT (Maximum Power Point Tracker) RS485 / CAN Communication Ports Load or Home power first with Zero Export to the Grid IP65 Ingress Protection High Power Factor

Just the usual 2c's worth of pure speculation. No, this is heavy overreaching speculation. That being said, something on this graph looks unusual. The first circle on the left could be described as a transient export, but for the section circled on the right, it looks like export of around 1kW sustained over approximately 10-15 minutes (just eye-balling it), and that's rather a lot. It just seems firstly like the energy balance is hard to maintain as the amount of PV generation at around 1500-2500W is fluctuating every so often, while consumption is also changing constantly but around the same levels of 1500-2500W. Throughout most of the day it seems like the battery can absorb the excess power well enough as it's charging. But around where the SOC is close to 100%, as the expected battery charge rate should slow to a trickle charge, something else is happening. It's as if each time the battery is called upon to supply power during a PV dip (cloud?) during that period, then as soon as the demand on the battery stops and the charging re-commences, the exporting to grid starts and lasts around 10 minutes. It's as if the charge rate that the battery is capable of taking at that time is mismatched to the PV generation demanded, as if the inverter is signalling bulk charging requirements, while the battery's BMS is limiting charge to a trickle charge. Hence the exportation to grid of the excess. My mind is wandering towards questions of battery and inverter compatibility, and I can see online that Goodwe has tested and certified the FreedomWon batteries with their inverter from a certain firmware version onwards, but even if that is done, maybe there's a case here where the firmware could be improved. Or I could be entirely wrong and the the CT coil is placed wrongly.

On an average day for an average user even in Winter you'll be fine, or you could make do. This is considering the 6.6kW of panels would generate around 20kWh, and you've got solar water heating and gas cooking to go with it, and you've got reasonable battery storage. On a clear Winter's day you could still get close to 30kWh if you had enough storage, but on heavy overcast days you might get just 5kWh. All thumbsucks based on personal usage along the Sunshine Coast. So of course there will be days (sometimes several in a row) where cloud cover prevents meaningful power generation. Question is how you want to handle that, and the question then is what municipality you're in and what do they actually charge for grid fees? If it's Nelson Mandela Bay, for a grid-tied user on TOU it's around R117pm excl VAT. I don't think it's worth it to go off-grid in this case, if it means running a generator, but that's just me.

Personal opinion to consider with caution only. I see what you're trying to do, or why, but you can appreciate, I'm sure, that it's not precise, because your East/West configuration pulls your production earlier and later in the day, and flattens the peak production. Perhaps if you do that, try to experiment with finding the peak forecasted value if you face all the panels East, and/or all the panels West. And then de-rate your Max Solar PV value in the SA setup, depending on the expected lower peak power generation that you see in those alternative forecasts. It could be for argument's sake that you say you've got 10% less PV, or 9000W estimated. Most days the forecast won't matter much, if your battery is charged by 10am in the morning.

This doesn't confirm the question above: Are these panels connected all 4 electrically in parallel to each other? For that matter, considering the upper limit of the MPPT Range (30-115VDC), could it even be that they are all 4 connected electrically in series? Both of those configurations could be problematic. I think it's the first question that really has to be understood in full before it makes sense to look at anything else. It is not clear, not known with certainty based on what you've said so far, whether the panel set's Voltage is matching to the MPPT range in your installation. Do you have a wiring diagram you can post, or can you ask your installer? Maybe a spec sheet for your panel as well or the actual model code of the panel to go with it? I was referring to the heat of the panels on the roof, not of the inverter, so that could be a separate issue. But if you can confirm that the panel configuration can be changed to a 2S2P (Two-Series, Two parallel), then the possible Voltage fluctuations with panel temperature would be less of an issue. The main issue is that in the worst case your MPPT input Voltage could be too close to the upper or lower limit of the MPPT range, so any fluctuations could push you out of the range.

Could you please confirm the model number of the inverter, and the make and model of the panels? And then confirm please whether you definitely have four panels in parallel to each other. Just from some general Googling, if it's the synapse 3.0+ Off-Grid inverter, the MPP Range is 30-115VDC. But if I look at the Max Power voltage of some 385W solar panels, the electrical parameters show Vmp of only just over 30V for example at NOCT, up to 35V at STC (example 385W JAM60S20 365-390/MR). All speculation, could be something else, and I might be running ahead of the issue without knowing the true facts, but if you've got a setup like that, then some shading or hazy skies, or heat build-up could cause the panel Voltage to drift out of MPPT operating range. I'd look at changing that to a 2S2P configuration, two strings of two in series, and then those two strings in parallel to each other.

Did nobody read what @DAVID-EC wrote? Either another 5kW in parallel or a single 8 or 10kW, Quickly back on-topic. All just speculation. Personal 2c worth is that I'd be cautious of adding another 5kW in parallel, from the point of view of the age of the product. Firstly the existing 5kW inverter should be just out of the normal warranty, and its expected remaining useful life is uncertain. Secondly, the older 5kW Deye seems to be close to the end of its model life-cycle, if a new 5kW model is already available, so future support could be anyone's guess. If you want to spend money now on upgrading the system in terms of capacity, I'd just look at spending money on a newer model at the same time for the long run. On a 60A supply if you don't intend to upgrade the inverter or panels, then the 8kW will be a good step up just to get a higher pass-through current. Otherwise if you have an 80A supply, or intend to upgrade your strings or battery bank significantly, I'd go higher for a 10kW. You'd still have the option in any case of connecting the older 5kW Deye via AC coupling if you maybe transfer one string off it, to get some use out of it while it's still good, if you don't want to sell it.

Going back off on a tangent. It's fair to say that the current Solis inverters have surpassed the older Sunsynk and Deye models that have been on sale in recent years, both in terms of specifications, and value for money. Maybe we should be asking how the newer Deye models stack up, and I think it was touched on some time ago. For example the Deye SG04LP1-EU 6kW is a more appropriate competitor for the Solis S6 6kW hybrid. Looking for someone to wade through the muddy waters and do the comparison. If it takes some mud-slinging along the way, why not.

It's right there if you scroll a little further down the page.

All speculation. First check maybe if you've got a battery charge rate limit set to around 70A. The solar panels will only produce what the battery system demands. Beyond that, I'm assuming your 7 panels are installed on one MPPT. Could obviously be wrong, I don't know. I'm wondering whether that inverter has set a limit on the power that one MPPT can produce. Considering the low start-up Voltage on your inverter, I'd try to spread the workload and experiment with connecting the panels in strings of 4 and 3 onto each MPPT and see if it makes a difference at mid-day. Three panels are obviously borderline on the low Voltage end, but the point would be to test if you can go above 3500W in total at noon when the Voltage is expected to be sufficient, and then you could consider based on what you see, whether to return to 7 in series, or add one panel to go 4+4.

Other than the fact that 25% of 60A is 15A... ...you could look up the document NRS 027-2-3:2023 from pg5: UDC Maybe look through pg37 in this doc: Requirements for Small-Scale Embedded Generation.pdf This is just to point you in a direction on where to ask questions, gain info or look for answers. I don't know what's the latest status of what is valid/applicable in your municipality (or anywhere else for that matter).

Hi @BigC - just to get back to this - and it comes back to understanding the existing configuration before making decisions. I'm understanding from the above that you had 3 strings, one on each Solis mini 2500. That means each string will have been with a max input current of 11A, and a max power rating of 2500W. I'm also understanding that you managed to combine 2 strings onto one MPPT of the Deye, and that you connected the other string to the second MPPT. You don't want to make changes to the strings on the roof, but you have access to the cables in the garage. If this is all correct, then the logical thing for me would be to connect the single string off from the second Deye MPPT, and connect it back to your Solis 4G again (this time with the Solis inverter connected via the AUX input). This will free up the MPPT on the Deye that can take a 5200W string at least. Is this what you were thinking of doing anyway? Also, sorry to bug and beat this drum, but these things stick in my head and then bother me.

Yes, this is the AC coupling method as described above, and I guess you can read more about in the manual of the Deye under the Grid/Aux port operating modes. Basically the Deye inverter acts as a controller and creates a mini-grid. The Solis inverter will respond to the grid signal from the Deye, generate power and the Deye inverter will then charge the battery connected as normal.

I wouldn't do that as a first choice. The inverter can in theory connect up to 10,400W of panels. Now I understand that it's a mixed bag of panels, but I'd start by maybe listing what you've got by make and model of the panels, and then seeing if one can come up with a configuration that could allow you to add that 4kW of panels without resorting to another MPPT. If it's a forlorn hope, if it doesn't work, then so be it, or if you've already gone through the thought process and concluded that you need the MPPT solution, that's something else, but from what you've written, I'd at least ask if this is an option.

I don't understand the existing scenario. What exact panels do you have now and in what configuration? I'm assuming "4k5W" is a typo.