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Hi guys, I have another n00b question please. I have an 8kW RCT Axpert Max inverter connected to 10x 540W solar panels. It is my understanding that the inverter supports a maximum of 4000W per input, yet my installer insists on wiring them all into one input. With a theoretical maximum of 5400W output, won't I be 'wasting' a potential 1400W by connecting them all into one input? Does it not make sense to split the panels into two arrays of 5 panels (PV1 and PV2), each into their own input, thereby also allowing for future expansion up to the 8KW maximum PV input supported by the inverter? What am I missing? Please see pics attached.

Yes please let me know if you manage to make a good comms cable and if it works. I'll then buy one too, just to have one that works. Solar Assistant is software that runs on a Raspberry Pi. They can sell you a Pi with SA preinstalled. Then you need a special RS232 cable from the Pi to the batteries and a USB cable from Pi to inverter. Very straightforward. If you go that route, hit me up and I'll talk you through it.

Hi - I've installed Solar Assistant like @P1000mentioned and it's been great so far. I can see exactly what my battery level is, and get Solar Assistant to automatically keep the battery levels up (even if it has to use grid on occasion). It mostly works fine, still not 100%, but I think unless you're buying inverters and batteries that are made to communicate with each other, and find installers who understand how it all works, you're always going to run into some issues (as I've had to discover the hard way). Thankfully we have tools like Solar Assistant to help us out, else it would be a real mess.

Thank you. Interestingly I did set it to solar + utility in charging priority, but it still didn't charge until I set the feed priority to utility/solar/battery. Anything else (SUB or SBU) and the battery was stuck at 20%. Also, you'd think solar first means solar and then top up with utility, whereas solar + utility would be shared between them. But I guess logic doesn't come into play. I'll just have to keep watching and adjusting, especially on cloudy days.

Hi guys, Hope someone can help me figure this out. I've got an RCT Axpert Max 8kW inverter, 2x Greenrich 5kW batteries, and 10x 540W panels. So we just scraped by Stage 6 on the (overnight drained) battery and the few hundred W the panels were producing this cloudy, rainy morning. During loadshedding I noticed the batteries were getting a small charge from the excess solar. Then when the grid came back they stopped charging. I have the inverter set to solar first charging priority and Solar Assistant automatically switches me to SUB from SBA when the battery percentage is low. I tried different settings, changing to solar + utility charge, nothing. The only thing that worked was changing output priority to Utility/Solar/Battery. Bam! Now batteries are charging at the full 2+ kW. The thing is I don't want to have to manually remember to switch to utility first every time. It's never an issue normally, battery charges full blast from excess solar, and if there's not enough solar, you'd think utility would do the rest with my settings. What's the story? Is it an inverter issue? Is it related to the Axpert cloudy day 'bug' I read something about? I'm on FW version 46.06 if that helps. Thanks in advance!

Hi guys, resurrecting this thread. I have the same issue - no communication between Greenrich U-P5000 and RCT/Voltronic Axpert Max 8kw. Just installed Solar Assistant today and using Emulate BMS mode to at least try get an 'accurate' reading of battery capacity. Battery to Solar Assistant cable on the way which will give me real-time data on battery state. But I SHOULDN'T need to jump through all these hoops if the installer supplied the correct comms cable between the battery and inverter in the first place, right? (Or was even aware that you needed one...) This shouldn't be rocket science and yet it feels like it is... I also wish my inverter supported solar energy priority (so I could direct PV power to charge the batteries first and fill in the load gap with the gird until the batteries are full), but alas, I didn't know any of this stuff before I bought into the solar system rush.

Ok guys, I really need help here because it feels like I'm going mad 😅 It SEEMS my issue is that the inverter has no clue what the actual battery level is. How do I know? See attachments. The way I have the system set up, it's in SBU mode. Which works great, and has been all week, as long as there's sun. Today is cloudy, so as expected, not enough solar to power both house and charge batteries until later in the morning. So grid gets fed in to supplement, which is fine. I have battery charge mode to solar only, since I'm happy for the grid to power the house while whatever solar energy I get is used to charge the batteries for overnight use and the occasional load shedding blip. BUT, here comes the problem. Inverter seems to think my batteries are above 80%\53.4V, so it's either trickle charging them, or worse, not charging at all and switching back to using battery mode because it thinks they have enough power. But they don't (as the single LED light in each battery would make patently clear). And that's where I think I'm going mad. My installer even switched me to utility priority remotely to try get the batteries charged (why, when I'm generating more than 1kw with solar?). They seem to be walking around the simple fact that my inverter is not seeing the actual battery capacity, and is therefore blissfully operating on wrong data. Have tried using the insaller-supplied comms cable, connecting to RS485 and back to CAN (installer insists it must be connected to CAN). But nothing makes a difference, even disconnecting the cable entirely. What am I missing!? This is driving me batty. Come 8PM and load shedding and I'm going to have two 5kw batteries empty and helpless. 🤬🤬🤬

This is also true. I've got just enough by the skin of my teeth with 10x540W panels and 2x5KWh batteries to stay off grid, and that's in summer. The system already costs me more each month (finance) than I'd be spending on electricity, but it's worth it to bypass load shedding and not have to rely on Eskon 80-90% of the time. Winter is going to be a different story. Adding another 5Kw battery and 10 panels blows any sort of ROI out the water, so I may just add some panels for the winter shortfall and suck up whatever on-grid energy I reluctantly have to use.

This is going to be a huge problem in a few months' time when everyone installing solar now is going to want to sell back to the grid...only to find out they can't!

Thanks, are there any hybrid 8kw inverters that don't cost twice what the Axpert Max does? 🤔

Hi guys, just had a new system put in with an RCT 8kw Axpert Max inverter. I can only assume the installer had the foresight to choose an inverter than can sell back excess PV power to the grid, but I've seen some comments here that this inverter can't sell excess power to the grid. Is this true? I have a smart meter fwiw. Thanks in advance.

Hi guys, Strange question, but is anyone able to recommend a cable I can buy to get my Greenrich U-P5000 batteries talking to my RCT Axpert Max? I believe this *should* work using the Pylontech battery setting but I'm not 100% sure. If anyone has any experience making cables, I'm happy to pay for one too. Thanks in advance.

I notice that the battery/ies stop charging or 'float' at around 53.4V, which is what is set in the inverter. At least that's what the inverter/app shows. Battery manual says cut-off voltage is 57.4V. Should I set float charge closer to 57V? There's also a back to discharge setting (currently 52V). Not sure what does what, so apologies for all these questions. Steep learning curve. 😅😬

Hi, just to confirm, the battery manual says maximum charge current is 80A. Does that mean for my batteries in parallel I should set it at 160A? (Not that I can as my inverter only supports 120A). The manual also says for better battery life I should set charge current at 48A (0.5C). Does that mean setting it at ~90A to 100A is optimal for the two batteries in parallel?

Hi, def RS485. See pic. Could be the wrong cable? In any case, look forward to Solar Assistant taking over and talking directly to the batteries. Hopefully it works as advertised.