BlakeSA

Don't let my experience put you off. The systems are amazing and really are life changing. Even with my small issue, I don't regret the investment for a second. 99% of the time it has been smooth sailing and we are loving not even having to check Load shedding schedules anymore. It's just this one little, intermittent bug that is causing some frustration and it might just be due to my slightly unorthodox installation requirement. If you can afford to do it, don't delay.

Thanks for all the suggestions folk. You really are a great bunch. I've had a relatively quiet 3 days with no persistent issues. I had just one disconnect and reconnect event. The disconnect lasted for less than 10 seconds and the inverter and battery backup handled it like a champ. Thanks for all the advice @system32 & @Kalahari Meerkat Some feedback, the CT Coil is definitely installed correctly - I just checked. The values are positive, and the value is usually close to my current trickle feed of 20W...but they do fluctuate. Usually between 16W-29W but I've seen them hit 0W as well. It's not inconceivable to me that it might spike into the negative from time to time as well, although I haven't seem it myself. This is why I am also suspecting that, due to the distance between my CT Coil and Inverter there are brief "spikes" where the signal is too slow and the inverter just sends a little too much juice to the Non-Essential circuit for a brief moment and this then causes the meter to get hit and disconnect. Only 2 issues with this theory: 1. When I have a disconnect, the meter stays on. When I have load shedding it switches off. So the meter itself isn't shutting down. There are also no errors or anything on the pre-paid meter itself. 2. According to my installer, many meters that receive a reverse power flow shut down permanently and somebody from the city then needs to reboot it. Apparently some kind of tamper safeguard. That isn't happening to me, but I have quite an old meter, so made it doesn't that? I dunno. Either way; I think boosting the trickle feed to 50W might be a way to test only 1 variable and see if it makes a difference, but as I said, things have been stable for the last 3 days without changing anything. I want to keep the experiments as controlled as possible and not implement all the recommended settings at once. Shutdown 10% Low Batt 15% Restart 20% Those were the installer settings, I haven't really tinkered there at all and the Sunsynk user manual hasn't been very useful in explaining what they mean. But non-of the disconnect-reconnect loops I've experienced have been close to those levels. The lowest SOC setting allowed by my Use Time is 30% between 05:00-09:00 and being in Cape Town, my PV is starting to produce at around 06:00 already. Thanks for that. I keep Grid unchecked because I want to recoup as much cost from my investment as possible and not grid charge my battery if I can avoid it. My PV setup is working a treat in summer and juicing up the battery nicely. I think I just need one more 5kW battery unit and I'll be golden. Right now I'm just hitting those SOC caps about an hour or so before the end of the time window and pulling about 3W from Eskom between sunset and sunrise every night.

Ja, that was what one of my friends also suggested as the possible cause. I've just struggled to create the conditions needed to test this hypothesis. From my (limited) understanding of the setup, a inaccurate CT signal would explain why ticking the "Limit to Load Only" option seems to resolve the issue; since that no longer pushes power from the Inverter into the non-essential circuit and doesn't hit the grid at all. And it would (possibly?) explain why the issues happen on time zone changeovers in the morning or at night (pulling from battery+solar and then suddenly switching to full grid or via versa) or after load shedding. Maybe due to the distance there is a delay in the CT coil signal and the inverter is pushing a tad more than what the CT coil is asking for and causing it to trigger a grid disconnect. Any suggestion on how to test this and force the hiccup behaviour without damaging any of the equipment? If the issue is related to the CT-Inverter distance, it will require some investment to fix it, and I'd like to be sure before I spend more money.

I'll give that a shot thanks. I doubt it will fix the issue, but it is probably still a good idea to do it anyway.

As per the opening post (3) the CT coil is quite far from the inverter…around 25m so more than the 10m limit in the specification. I’m not sure if the installer installed it correctly at that distance and wouldn’t know what to look for, but is it possible that that is the culprit?

There isn't load shedding. Or there wasn't. My prepaid meter was also still on. My inverter just disconnects from the grid or thinks there isn't grid present. My appliances on the non-essential circuit also switch off. I can't explain it; but my understanding of how this stuff is supposed to work is also very limited.

Photo of Grid Connected (unstable) The "hiccups" continued for about 25 mins until I grew tired of struggling at which point I just unchecked the "Limit to Load Only" option and things calmed down. The hiccups stopped. It's not the setting I want as I will now be using grid to heat my geyser in the morning instead of PV, but for now it's the lesser of evil as the constant disconnect-reconnect can't be good for the inverter or my appliances on the non-essential circuit I'm starting to lose hope.

Some interesting developments. I thought I had to wait for load shedding or a low SOC to test something, but that wasn't required afterall. I have these use timer settings: At 19:21 my SOC hit 70% which is the threshold so power switched to gird. As expected. The lights flickered for a millisecond but then I had ONE grid disconnect. System reconnected to the grid a couple of seconds later. Annoying, but no biggie. Then at 21:00 on the dot, when a new Time window opened and the system could dip back into battery, the hiccups started. Photo of Grid Disconnected It seems to depend on when I look if the light is on or not. Could just be a timing issue.

Thank you for confirming! This was my understanding as well...but this is the exact setting that sometimes triggers the "hiccups". I think I've made a breakthrough though. I suspect the issue might be related to the "Grid Charge" checkbox that was disabled on the battery screen. I've enabled it again now. When my load shedding ended 18:00 the hiccups didn't happen as expected. However at around 19:20 when my SOC hit 70% (as per the Use Timer setting) I had one hiccup only and now things are running on the grid. Load should switch back to battery at 21:00 so I'll see what happens. I suspect that if the SOC is lower than the User Timer limit when load shedding ends something goes wonky. It's not an issue during the day when the PV keeps the SOC above the limit, but during the night, if load shedding hits the SOC dips below the limit and when load shedding ends, the hiccups begin. I'm going to test it tomorrow morning. I have a 4-hour 22:00 - 02:30 scheduled, so battery SOC should be at 30% by 07:00 tomorrow. And then some more Load Shedding at 08:00-10:00 should make things spicy, but the PV should carry me through if it's not too cloudy.

I have the Sunsynk dongle and get some data on their app or online on their site. If I know where to look I can post some of the appropriate graphs. These seem to be the grid parameters that can be graphed out for a specific day.

Not much unfortunately. Wouldn’t know where to start. I do have access to the SunSynk app and website for data logging but wouldn’t know what to look for. Loadshedding just ended here with no farfare. No hiccups. Everything working as expected. Switched on a stove and kettle just to stress test and power flowed exactly as I wanted it to. SOC was high, but PV was low (sun is setting) so the load was pulled from the inverter and battery mostly. I guess I’ll have to wait for the hiccups to start again to post some answers to the questions.

All good. I appreciate all the suggestions. The lights only flicker momentarily when the grid disconnects...even though they are on the UPS circuit. PCs and TV on the same circuit ride out the disconnect with no drama. It's just the LED down-lights, but I'll narrow voltage range in the Grid settings anyway. Can't hurt right? I also think it might be something to do with the SOC%. Some conflict in the priority somewhere. The issue seems to be more prominent in the morning when the battery has been depleted overnight. I figured 30-40% SOC and whatever PV can be generated in the morning hours when the sun comes out is enough to carry me through loadshedding if I manage my loads. And if there isn't LS and if there is grid, even better. It can just top up any shortfall. But right now "hiccups" as I'll call these disconnect-reconnect cycles, have started in the morning on 3 or 4 occasions so there might be something here. Maybe triggered by a peak load or something, but so far I haven't found a trend. Nor what is causing it to auto-correct after a while. I'll keep an eye on the SOC next time. There was an exception though. One night my SOC was at under 60% at 22:00 after 2 hours of loadshedding and we were heading into another 4 hour stint 00:00-04:30. This made me nervous as I know from experience that my battery isn't big enough to get me through the night so I do have some grid use of 300W continiously. So I did a grid charge to get me through the load shedding. Decided to stop it manually around 23:20 when I went to bed (SOC was around 05% which I thought was enough) and the moment I ticked the "Use Timer" on, the hiccups started again. PV was 0W obviously, SOC as 95% as stated and grid was active as load shedding hadn't started yet. It had me baffled.

If I recall correctly it stays on; but I'll have to check. I didn't pay particular attention to it. I have load shedding right now, but it should be over in 30 mins or so. That's usually when the hiccups begin which is why the installer and Sunsynk have attributed it "grid instability" but I've since managed to initiate the hiccups in non-load shedding times and also stopped them by just ticking that "Zero Export - Limit to Load" box. I'll report back as soon as the hiccups start again...if they start again.

Haven't yet implemented @GreenFields' recommendations. Would like some clarity in the impact first. BUT just switched off "Limit to Load Only" on the System Mode 2 menu again. This is what would usually usually cause the grid disconnect / reconnect cycle to start. Nothing this time. I also then switched on the oven (non-essential load) and PV production spiked and I could see the power to the house increase in the diagram...just as expected. So ja, now I'm even more stumped. I'm starting to think it might have something to do with low PV production and low SOC% on the battery that's also playing into the behavior; because right now SOC is at 100% and PV can easily product 3000W if there is sufficient load. Of maybe this observation is a complete red herring... ¯\_ (ツ)_/¯

1. SOLAR EXPORT The Sunsynk user manaul says this about the "Solar Export" option: "Tick this box if you wish to export your solar power back to the grid." Which is very confusing if "Zero Export" is described as: "Tick this box to not export power back to the grid (the CT coil will detect power flowing back to the grid and will reduce the power of the inverter only to supply the local load)." The 2 options seem to be contradictory? Or am I missing something elementary? 2. PRIORITY LOAD "Tick this box if you wish to set the solar panels to give power to the ‘Load’. If you untick this box, the solar will send power to charge the batteries." I want to power my essentials (and if possible my non-essentials) from the solar production. Why do you recommend unticking this option? 3. VOLTAGE SPEC Regarding reducing the allowable voltage band from 185V - 265V to 207V - 253V...wouldn't narrowing the band make things more unstable? I've only gotten the F56 DC_VoltLow_Fault error once before and I don't typically get that error at all when the Disconnect/Reconnect loop is occurring.