wolfandy

I have a single pole breaker like this. Installed after the main incoming breaker and before the inverter feed.

It's usually not just the frequency - same also with the grid voltage. Which is exactly why I have a smart breaker in my system to manually disconnect from the grid when I don't need it. So that my house gets 'clean' power and does not follow the Eskom mood swings...

+1 When running inverters in parallel, both inverters should be connected to the batteries via a common bus bar. I don't think it is possible to run a parallel system with each inverter having it's own battery. Also don't know if it is possible to run different batteries together in a system. I'd expect that you would run into all sorts of problems - as you are now experiencing. I would say that you have 2 options: Sell one battery and replace it with the same brand as they one that you are keeping Run each inverter separately (not in parallel), which would mean splitting your DB board across the 2 inverters I would recommend option 1

Am running 2x 5kW Sunsynks with 6x Pylontech - and am generally happy with my system. Yes, I do have a small issue with my system in that my slave has a higher battery draw when the system is connected to the grid. But I would call it more annoyance than issue. I have raised it with Sunsynk and they want me to send in both inverters to be able to replicate the issue - and to me that has not been worth it. The issue only presents when connected to the grid, and I am manually disconnected from the grid 95% of the time - so it is not bothering me really. Other than than, the system is rock solid and absolutely stable. I would recommend 2x 5kW over 1x 8kW/10kW to get the additional MPPTs for greater flexibility as well as redundancy in case there is a fault on one inverter. Batteries and both inverters connected to a common bus bar From what I understand, it is best to split PV strings across both inverters - e.g., rather have 1 string on each inverter instead of 2 strings on a single inverter and nothing on the other I would probably go with 1 battery and additional panels. I think you will otherwise struggle to get you batteries charged Your sparky will need to check. But if you install a 2nd inverter, then your initial inverter connection should be fine

Same on my side. I think this is because the BMS is only connected to the Master - and the Master does not seem to communicate the details to the Slave

Thanks I'll leave it to others with better knowledge of your inverter to advise

I am not an expert with those inverters. Am tagging @Coulomb to maybe chime in with his endless knowledge It seems that your inverter has 145V max VOC on the MPPT, so we would need to know how your panels are wired (e.g., 3 in series and that 3 times in parallel - 3S3P) A quick search here in the forum produced this thread, which might be of interest for you Where are you located?

Thanks @Ninoevans I am not sure if the data is an hourly snapshot (Watts generated and used) or cumulative Watt-hours (Wh) for each hour. But as an estimate it suffices. Based on your data, it appears that you have generated a PV surplus of approx. 5kWh during that day. Not knowing your batteries SOC makes it difficult to tell how far the batteries were discharged/charged, but based on your approx. 7kWh deficit from your chart (and not knowing how much grid was used for that), it would make sense that your PV is not able to fully charge your batteries. If you are discharging your 2x US3000 down to 20% (recommended for the older A/B models), then your surplus PV would not even be sufficient to charge them back to full. With the added US5000 that charging gap becomes even bigger... The other thing that I noticed from your charts is that your peak PV production is around 1.6kW - which from your total 3kW of panels appears low (depending where in the world you are based and which season it is for you). Which inverter are you running and how are your panels wired (e.g., all 9 on a single string in series)?

Hi @Ninoevans we'll need some more details to be able to help you. Could you please post some charts of your system from a typical day - e.g. load and PV production, battery power and SOC. Then we can better see what is going on with your system.

No way this is true. PV production is usually shaped like a bell curve. So the statement that 'the panels will produce 7kW all the time during the day' will never be true. Then also factors like direction of the panels have an impact on production. I am also based in CPT and here is the production data from my strings from this morning. Yellow is 6x 580W (=3.5kW) panels facing the morning sun and blue 8x 490W (=3.9kW) panels facing the day sun (main direction). You can see the ramp-up on both string. The yellow one makes a steep jump around 07h30 as the sun comes over the mountain. And you can see the drops due to cloud cover on both strings. By almost 11h30 neither string produces the nameplate capacity. So getting a constant production 'all the time' is just plain wrong.

Thanks @Zeus-JKR On the battery current, when you zoom in on the time period that your system is running on Grid (e.g., 02h00 - 04h00), is the battery draw still the same for both inverters? Strange - so we both get a higher Essential Load on our Slave, but seemingly caused by different things... Have you raised this with Sunsynk Support? Are you also based in SA?

That's the way it should be. Same cable lengths to each inverter from busbar? I am getting the same voltage reading on both inverters. Max. 0.1V difference I also get something weird running on grid. My Total Load is relatively even split: However, when looking at my Essential Load, the Slave is carrying a higher load than the Master: And for some reason, the Master is reporting a Non-Essential Load while the Slave is reporting a negative value for Non-Essential Load. This is particularly strange as I have no load connected to Non-Essential. It appears that the Master is pushing current across to the Slave: When disconnected from the Grid, Non-Essential Load is 0. Are you seeing something similar in your system? The other thing I have noticed is that the Slave is drawing significantly more from the batteries when running on Grid: Does this also occur in your system?

In my system, both report the same battery voltage. How are your batteries connected to the inverters? If I understand correctly, your system also runs ok when only on batteries but has unexpected behavior when connected to grid - is that correct?

@termdj: You posted your question twice. See my response in your other thread

If I am not mistaken 120V or 125V This is barely enough to get the MPPT started - if at all. So I am not surprised if you are not getting any production out of these strings As they are facing different directions, this will not help you much. Either put all panels facing the same direction or add more panels to each string to make sure that you have sufficient voltage on each string to get the MPPT started