GreenFields

Firstly, maybe check on the Li-BMS screen what's the battery max charge and discharge rate indicated there. My suspicion is that the BMS and batteries are not the problem, and that it is ready to receive max charge, since it is not switching off the batteries in Voltage-mode. Personal 2c, I'd look toward the parallel setup of the inverters, whether they've got communication as master and slave, and what the individual contribution is to the 300A charging. It just sounds on the surface like only one of the inverters (290A peak) is doing the charging. Of course I could be entirely wrong, but that's where I'd start checking all the same.

Stupid question, and I hope you're not insulted by it, but I have to ask it anyway. I see the Felicity IVGM5048 5kW is available in a single-phase and three-phase version. IVGM5048 (5KW monofásico/trifásico)) - Felicity Solar What are the chances you've got a 3-phase version, and are exceeding the loading on just one connected phase?

3x550W panels sounds like overkill for a 50l geyser. Check if maybe 2 will be enough.

If you are going to get a second Deye inverter, then definitely split your panels between the two inverters. Don't keep it all on the 1st inverter. The simplest will be to connect either the East or West string of 8 panels to the new inverter. If you intend to add more panels, then you could split up the strings such that you use for example 5 panels on each string, one string per MPPT. Even without buying extra panels, doing that alone will allow you to tap into the full 8.8kW of panels (azimuth to consider) that are connected to your current inverter. Right now you are limited to 5kW AC, and 6.5kW DC, so let's say up to between 2.3kW and 3.8kW that you simply can't use on sunny days. That's a decent amount of extra power for charging batteries or running the geyser, or for any other thing you want to.

And for that, yes, you've got options for future expansion. I think now is not the time to make further changes, though. Rather just use and monitor the system as-is for now, then once you've installed the aircons, you can keep monitoring a bit more, and then only decide your next steps. Whether you add more panels onto any given string (up to 8 should be okay), or double-up a string with another in parallel, I think you should decide based on tracking your actual usage history.

Personal opinion: Your best bet is just to connect the Sunsynk 5kW first with an amount of batteries and panels that you calculate from your daily usage. It's a bit small, though, to go off-grid for your whole house with just a 5kW inverter. It will probably be tripping too often. You could divert a fair amount of power to your loads with it as long as you stay connected to the grid, but for going totally off-grid, you'd either want an additional 5kW inverter, or otherwise maybe you could then use your 3kVA Axpert to feed some dedicated loads. Either speak to an installer to advise on the batteries or panels you need, or else if you say how much power you use per day or per month and what time of day, someone here could maybe give you some high-level ideas.

I'm concerned that you are confusing the input current coming in from the panels, with the output current going towards the batteries. The 5kW Sunsynk has got a 13A limit on the input current, yes, but on the output side you can get up to 120A charging current. So saying you want to "bypass" the 13A limit on the 5kW Sunsynk by using a 60A (output) Microcare MPPT makes no sense. What size battery bank are you talking about here, and what panels will you have connected?

Did the installer ever consider that he could connect the panels in parallel? That is to say, if you wanted to keep the 10 panels pointing North for peak daytime power generation, that he could have connected two strings of 5 in parallel to each other, instead of one series string of 10? What are the Voltage and Current specs of the panel? Edit: 13.25A Imp as per spec sheet. Pointing the panels Eastwards and Westwards spreads the power throughout the day more evenly, which can be a good thing if it generates at a time when you need and use the power. However, the peak is lower, and the overall total power is also lower. A possible good compromise could be to connect 10 North in parallel, and then 5 to the East and to the West each respectively. Bottom line, I don't think you need to be despondent about your system, I just think your installer should give more consideration for all the options and your needs before doing the installation.

Looks like one would have to upgrade to the 12kW Solis, as per the post of @Powerforum Store above, to get a screen.

If the inverter was tripping, you'd expect the load should also be interrupted, but it just keeps operating. One would also maybe notice if the power goes off. @Slarty can you see if the load is just being transferred to grid or battery during that time? What panels do you have, how are they connected, and can you show the PV1 and PV2 Voltage during that PV outage, for both inverters?

No, it's the "SOC" value (State-of-Charge) that will regulate to which percentage you can discharge the battery. What I'm saying is to change the "Power" value to zero, meaning that you will not be allowing the system to take any energy from the battery. It's probably sitting on a default 5000W if you haven't made changes to it before. Otherwise, set it to a low value like 100W, so that in the worst case any discharge coming from the battery will most likely just be used up slowly in your house for your own baseload power, then you can charge it back up later, if you can schedule your settings changes with the Raspberry Pi. Not guaranteeing that it will work, just suggesting you try it.

Try to use that "Selling First" mode (disable Zero Export), but in combination with the Time-of-Use Timer, where you set the battery power to zero (0) during the time slot where you don't want to be exporting battery power. I think this is one of those use-cases where you might end up being dissatisfied with the on-board functions of the inverter, and rather want some form of automation assistant for different times of the day.

If you can source the same panel again, you can have 14 panels in total, basically two strings of 7 panels, one string per PV input, with no further questions or concerns. All within spec, all within limits. 10.64A falls within the 11A MPPT limit, then 7 x 48Voc = 336V is comfortably lower than the maximum 500V MPPT Voltage, and lastly, 14panels x 420W = 5880W will be comfortably within the 6500W PV input limit. I'm not saying this is the only or best panel layout, just that it doesn't push any boundaries, and it's quite possibly good enough. In general your panels will be limited by the current of the lowest-output panel. In this case the 10.64A at STC. More than that, this specific inverter model has a limit of 11A current on each MPPT, at least according to the dataplate, so it will most likely keep clipping current down to that level anyway. Not much point in upgrading to 550W panels or similar, unless your inverter can be upgraded to take 13A input like later versions. At the simplest view, it's best to stick to the same panels or similar in output. Voltex's website seems to have good pricing currently on similar-output Canadian Solar panels, 455W CS6L, that look to be a close match for your panels, in case you don't find the exact ones again. [Edit: not an 11A panel as I thought. Different specs, different panel] Disclaimer: Just a personal opinion. To be checked professionally by your installer.

I don't think it matters much. May as well just keep it lower. There's enough time in the day to charge full up. In theory you'd be limiting to 2kW charge instead of 2.5kW, when your solar peak at mid-day could be 3.6kW. Only if you find that your battery is not charging full up, then change it to 50A but I don't think you need to.

Searching around, some sites seem to suggest a saving of up to 84% heating costs with the 200l IHP geyser, suggesting you're using 3.4kW less heating power, when compared to a 4kW element on a conventional geyser, because this heat pump only uses 0.6kW. That might be confusing Power and Energy. The COP for this IHP is 4.11, in other words, you are getting just 0.6 x 4.11 = 2.466kW - let's just call it 2.5kW -of actual heating performance. So you're going to have to heat the water longer, just to reach the same temperature, compared to a normal 4kW geyser element. The savings wouldn't be 85%, rather something lower, more in line with typical heat-pump performance. Looking here at an ITS 3.6kW with a 4.18 COP for example. I'm not saying that heat pump technology isn't better than a conventional element, of course you'll use less power energy overall. I'm just wondering whether this 2.5kW performance is good enough compared to the 4kW that it's supposed to replace, or whether it's not better to go with a separate tank combined with a separate more powerful 3.6kW or 4.5kW performance heat pump, for getting hot water quicker when you need it. As always, just my layman's 2c, open to correction.

The total PV output is 12.5kW, so if this was say 6kW AC loads and the rest charging batteries, it's still well within rated power. Not enough info to say. Exceeding the 8kW AC output should not be normally possible.

Geyserwise Eco installation, one for each geyser, and 3 panels per geyser. As a possibility, if you're not planning to upgrade the inverter setup with panels.

For me in an ideal world you would have an engineer only involved at the point where an inverter is tested for adding to the municipality's list (CoCt) of approved inverters. That approval process should then include a standard wiring layout, and after that any electrician should be able to sign off that an installation conforms to that particular layout. The problem I'd see is when there are unique designs, somebody has special requirements, tries special tweaks, and then I would not leave it in the hands of an electrician to design to those special needs.

You could also check the dip switch settings on the batteries. Someone in a previous thread had the issue that the dip switches were wrong, so the batteries were not set up correctly as master and slave(s). I would check this first before changing the wiring on the batteries, considering that you say it works fine as expected when the inverter is operating in Voltage mode. The issue is, the inverter can only "see" one of your batteries via the BMS.

What you are saying makes perfect sense. Here you should take my comments with a pinch of salt - rather take it from someone who actually uses or installs Solis - because I'm just comparing the operation to my Deye hybrid which is the competitor product, and I'm looking through the manual and spec sheets. But yes, the theory is, with the CT cable/CT coil that comes with the inverter, it should be able to divert solar and battery power to the non-essential devices on the grid port, and that is all controlled by the current-sensing feedback that this CT cable gives to the inverter. It should inject just enough power to the grid port, so that you don't send power past the CT coil and on to the grid. Works well enough on my Deye, but it only works as long as there is power on the grid. The non-essentials like the geyser would then not be backed up by battery. Regarding the panels, I think you should find an online solar calculator and work out for your location what would be the actual power generated for those panels facing South-West, before installing them, to see if it's worth it. I understand the thinking to make the best of the situation, it's just naturally sub-optimal. I think your best bet would be to take special attention with the choice and layout of the North-West panels, to get the best in terms of efficiency-level of the panel, outer dimensions, Voltage level, etc to squeeze as much as you safely can facing that direction. On good sunny days the 8 panels should still be enough to replenish your battery

The question of redundancy is I guess something you must go with your gut on. If you install a bypass switch, which you probably should, you could still run on the grid, and my personal 2c is that the loss of not generating power for the couple of weeks you'd be idle for repairs, is not going to outweigh the cost of the upfront installation of a 2nd inverter. Different story if you're off-grid. Looking at the specs of your system, to just go with a single 8kW Solis, and just install non-essential loads like the geyser to the grid port. This is considering the recommended 0.5C discharge rating on the 14.3kWh battery, and the approx 6-7kW of panels to be installed, and the 50A pass-through of the inverter, 200% 10-second surge rating of the inverter, I think at least on paper you'd be fine. Otherwise, if it's a question of the capacity of 2x6kW Solis inverters, maybe even to consider future expansion with another 14.3 battery, you could consider maybe a single 12kW Solis S6 inverter for just a shade over the cost of 2, and not worry about any issues of running in parallel mode. Available on the powerforum store website. Last comment, would be to avoid installing panels on your South-West roof if you can, rather fit it all pointing Northwards.

Coming back to what I said earlier, what you could do for now is to set the "Power" value lower during the evening Time-of-Use period when the underfloor heating is coming on. If you know that you draw up to 6000W at that time, change the Power value for example to 1000W. That should cover the baseload more or less, and the 1000W will be all that's coming from the battery, the rest from grid. Even when using Zero Export to CT and sending power to non-essential loads, at least the battery drain will be limited to that 1000W. Or play around with the best setting/value that is equal to your normal loads excluding the underfloor heating.

Pure speculation. Just for understanding. What does the load graph look like at the same time? Just trying to see whether maybe that one MPPT is tracking the AC load fluctuations while the others are tracking the DC battery charging. Considering that the slave's DC temp is higher, it doesn't look like an overheat throttling on the Master. Is this setup running on-grid or off the grid? Are you using battery priority or load priority? Could there be any extra dust or dirt on the panels in question that's not on the rest? Bird poop?

Last time I asked this from Deye's email support line, they said it could not be done, ie. also could not be implemented in the firmware. You would need a way to set or change the work mode based on the time of day. Maybe someone else can advise whether Sunsynk's online portal does it, or a third-party home assistant can program this feature. Only workaround I used was to limit the power at night using the time-of-use feature, but that's one of my few unsatisfactory points on my inverter.

The time of use settings (including power limit) only apply while the grid is on. Once the grid power goes off, the battery charge/discharge current limits will apply.