sgs

Hi all! I've been lurking here for a while, trying to stay relatively up to date for when I want to take the plunge to solar myself. That day is now getting closer, and I've been looking at inverters. The Sunsynk/Deye range appear to come highly recommended, and appeal to me since they will offer the most flexibility in the long run. I am however confused by a few things, so I'm hoping the kind folks on this forum can please offer some advice? I need to decide between the 5kW and the 8kW models (though obviously prefer the smaller one). I also need to decide whether I want to put most of the house on it, or just some basic essential loads, with the rest left as non-essential. To figure this out, I need to understand how the inverter blends power. I understand the 5kW has up to 7.7kW of passthrough. If one has that installed with 5kW of solar, and wire everything on essential, midday sun is shining, and then switch on a 3kW kettle, 3kW Geyser and 500W of other stuff. What will happen? Will the inverter push 5kW from solar and supplement the remaining 1.5kW from grid? (This is how I understand it - so as long as there is grid, you can effectively have over 7kW of loads running, just not all off solar?) Then, same inverter, middle of the night, with roughly 5kW of battery hooked up to it (0.5C battery). This can only supply up to 2.5kW before the battery will get upset, so what happens if suddenly 5kW of load is switched on? Will the inverter use 2.5kW from battery, and pull the rest from Eskom? And then finally, same scenario as above, but Eskom goes on a loadshedding spree in the middle of the night, and the 2.5kW limit of the battery is exceeded. I imagine the battery will trip and leave you in darkness - but will the inverter manage this and trip before the battery? At the start I imagine I'm going to go quite light on batteries, since they add significant cost to a system. I'd like to have some battery available as a backup for load shedding and potentially cycle it for the early evening loads, but it looks like the best bang for the buck will come from solar during the day, not at night. But, I don't want to half-bake the wiring and have to rewire house plugs and things at a later stage when I do decide to add more battery and want to move more loads to essential - so I want to get that right from the start. Our peak load (without geysers and pool pumps) will currently be mostly under 5kW, but I am worried about the day that someone plugs in a toaster without thinking and potentially leaves us in the dark. If it the inverter will indeed blend grid up to 7kW without keeling over, then I'm feeling reasonably comfortable that we can drive the entire house from it, but leaving geysers and pool pumps on the non-essential side. (And maybe just having a couple a plugs on the grid side, should one ever need to run high-wattage appliances?) Thanks!

Thank you for the help - much appreciated! I tried lowering setting 29 last night by 0.5 volts, and sure thing, the inverter kicked to grid at 49v this time, not at 49.5 as before. So now will monitor SOC more closely and slowly lower the safe discharge voltage until a reasonable DOD is achieved.

My apologies if this has been asked before, but I have trawled through this forum and read a lot about the Axpert and Pylontech combo, and haven't been able to find a difinitive answer. I'm hoping that someone can maybe throw some light on this funny problem? I have a Mecer SOL-I-AX-5M (Axpert 5kva/4kw) - as it came out of the box a few years ago - no firmware mods/hacks etc. The system has been running for years using a bank of lead-acid batteries, but the bank has deteriorated to the point where it needed replacement. So it was "upgraded" to a Pylontech UP5000 battery. Since there are warranty concerns when connecting these batteries to Axpert inverters, the installation parameters supplied by Pylontech were followed to the letter. However, the system isn't behaving as I expect it to behave, and barely uses any battery before failing over to the grid after sunset. The settings are as follows: Program 01 = SbU Program 02 = 50A Program 05 = USE Program 12 = 48V Program 13 = 51V Program 26 = 53.2V Program 27 = 53.2V (not specified by Pylontech) Program 29 = 47.5V The behaviour is that the battery charges nicely during the day, and then starts feeding power back at night. I expect that it should drain until the voltage drops under 48V, but it only runs down to 49.5V. The moment it drops to 49.4V, it falls back to grid, only to go back to solar the next day again. (The battery SOC leds still show between 4 and 5 lit at this stage, so there is still plenty of juice available, and I doubt if there was a chance that it could have dipped down to 48V because the power draw on the system is very linear.) I've read a thread here that suggested setting Program 29 to always be 2V lower than program 12, but I haven't seen this mentioned anywhere else - and also does not compute with the settings supplied by Pylontech. Could this be the reason for this? (And if so, is this a "bug" in older Axperts maybe fixed in newer models?) The plan is to get ICC or Solar Assistant installed to monitor and control the inverter according to battery SOC, but if the basics aren't working, then I'm not sure that any of those will just magically "make this work". Any suggestions would be very much appreciated! Thank you!