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RCT-Axpert 5K unexplained/mystery behaviour - no PV input (panels) icon.


Cassie
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About 4 months ago my slave RCT-Axpert 5Kva 4Kw suddenly stop showing the panels icon, thus no PV input.  I replaced the MPPT board with a new one.  But no success.  Then send it to Mecer and they replaced the mother board - yet again no success.  Return it to them and I suppose they replaced the mother board again,  They sent me a video clip of the inverter on their test bank, working perfectly in parallel with the firmware U1 52.30  which is the firmware on the Master (back home) according to the technician who repaired it.

I received it, installed it and switched it on as the slave unit - but again no display of the panels icon.   I haven't checked the firmware, but I'm not sure if different firmware will cause that the panels (PV input) not being recognised/shown - I tested the PV input on the inverter terminals and it displayed 131.7v.

Please help!  I need to run 8000w.

Slave.jpeg

Master.jpeg

Master.png

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6 hours ago, Cassie said:

About 4 months ago my slave RCT-Axpert 5Kva 4Kw suddenly stop showing the panels icon, thus no PV input. 

Possibly because that was the start of the cooler weather, and cooler panels have higher voltage.

6 hours ago, Cassie said:

firmware U1 52.30  which is the firmware on the Master (back home)

52.30 is quite old. I would first update to more recent firmware: patched firmware version 73.00e (NOTE: NOT 73.00 factory firmware, you'll eventually get fault code 90) or factory firmware version 72.70. [ Edit: there should be no need to update the SCC firmware, especially when running patched firmware. ]

6 hours ago, Cassie said:

I tested the PV input on the inverter terminals and it displayed 131.7v.

That is higher than the MPPT range. That could explain why it works on their test setup; I'd expect the test PV voltage to be within spec (< 115 VDC). Though I'd expect the PV icon to turn up, but perhaps flashing. Anything over 130 VDC will cause reduced solar charging power power output. It may be that you need to rewire your panels from 3S to 2S. But first, try update firmware.

Edited by Coulomb
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6 hours ago, Coulomb said:

That is higher than the MPPT range. That could explain why it works on their test setup; I'd expect the test PV voltage to be within spec (< 115 VDC).

Thanks Coulomb,  but on the sticker it shows:  Max Solar Voltage (SOC):  145VDC  (I included the stickers in my previous post).

The Master runs smoothly on little more or little less same voltage also on 6 panels since installation in the beginning of 2020.

I will first upgrade this dysfunctional, unsupportive and unwilling piece of ... technology to 73.00e .   I suppose the update and instructions are on Powerforum somewhere.

Thanks again Coulomb.

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52 minutes ago, Coulomb said:

Probably; if so, they will point here:

https://forums.aeva.asn.au/viewtopic.php?p=70827#p70827

Thanks Coulomb,  I noticed on the sticker it shows:  Max Solar Voltage (SOC):  145VDC.   But in the manual I see the PV Array MPPT Voltage Range is 60~115Vdc.  I wired my panels 2 strings of 3 x 30Vmp in series per Inverter (as in the diagram below) giving me 90Vmp per string and well inside the parameters of 60~115Vdc.  

After they replaced the motherboard (and when it showed no PV input after receiving it back) I checked the DC volts on the inverters and it was 88V on the broken Slave and 90V on the Master (also within the range).  

I never thought it will go up as high as 131.7DCV.  This measurement was actually on the coldest part of our winter, with snow on the mountains.  But I suppose it will not damage the inverters as the Max Solar Voltage (SOC) is 145VDC;  am I correct in assuming this?

 

panels layout.jpg

Solar panel.JPG

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3 hours ago, Cassie said:

I never thought it will go up as high as 131.7DCV.  This measurement was actually on the coldest part of our winter, with snow on the mountains.  But I suppose it will not damage the inverters as the Max Solar Voltage (SOC) is 145VDC;  am I correct in assuming this?

Yes, there should not be damage as long as it doesn't ever exceed 145 V. It sounds like you're safe there.

The question is what voltage it will start at. I think of 7°C at night as cold here, so I don't know about cold weather starting 🥶.

3S of those panels should be fine. In fact, 2S might not be enough voltage under other circumstances.

So your problem is a bit of a mystery.

3 hours ago, Cassie said:

I noticed this is for a PC, is there perhaps a iOS (Apple Mac) version for the installation software? 

No, the manufacturer hasn't ported the reflash software to anything other than Windows, sorry. Can you perhaps run it in a Windows VM?

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Thanks Coulomb,

Another mystery happened this afternoon.  I checked if the firmware was the same as the technician said.  I found it to be the same and I waited for the display to switch back and viola the panel icon appears and after a view seconds the battery showed as well.  It showed that it is charging although the charging led stayed on continueosly (not flickering).  I left it on and after about an hour al 6 leds were on both Pylontechs were on (as it was before I switched the inverter on) but the their voltages dropped from 53V to 49.1V on the Axpert, so it appears if the floating charge is not functioning.  I suppose I will only be able to be sure of that when I got my Raspberry Pi back which is to be updated as well.  

To see if the panels are supplying current I wil tomorrow change 1 to SOL and see if I do get AC power from the inverter.

Edited by Cassie
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  • 2 weeks later...
On 2021/08/15 at 3:25 AM, Coulomb said:

52.30 is quite old. I would first update to more recent firmware: patched firmware version 73.00e (NOTE: NOT 73.00 factory firmware, you'll eventually get fault code 90) or factory firmware version 72.70. [ Edit: there should be no need to update the SCC firmware, especially when running patched firmware. ]

I noticed last night that the SCC's firmware on the repaired inverter is 00.00 (see image below) while the other one is 1.24.  I suppose that this can be the cause why this inverter sometimes connect to the pannels and sometimes not?  i'm planning to update both inverters to 73.00e as you suggested.  Will this also fixed the SCC firmware? Or is there additional firmware for the SCC?

Another question:  I understand that it is kind of dangerous to update.  According to my supplier if something went wrong it can brick the inverter permanently, is that so serious?

 

Thanks

Cassie

SCC Firmware_Working Inverter.jpg

SCC Firmware_repaired Inverter.jpg

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47 minutes ago, Cassie said:

I noticed last night that the SCC's firmware on the repaired inverter is 00.00 (see image below)

Is that with PV connected? If there is no PV connected, then there will be 00.00 reported. The solar charge controller only gets power from PV, not from the battery or AC-in.

If however there is valid PV connected, then U2 00 00 indicates that the solar charge controller is not working / damaged. Or they left off one of the cables inside.

Quote

while the other one is 1.24.  

01.24 is the oldest of the SCC firmwares. However, it works just fine, especially with patched firmware (we have special code to overcome some of the limitations of 01.24; I can't recall the details off hand). Even with factory firmware, it should be OK.

Quote

i'm planning to update both inverters to 73.00e as you suggested.  Will this also fixed the SCC firmware? Or is there additional firmware for the SCC?

As above, we avoided having users need to update their SCC firmware with workarounds in the patched firmware (such as 73.00e). So no, while there is later SCC firmware available, if you plan to use 73.00e anyway, there is no advantage to updating the SCC firmware.

Quote

I understand that it is kind of dangerous to update.  According to my supplier if something went wrong it can brick the inverter permanently, is that so serious?

I cover it briefly at the end of the upload instructions (ignore the obsolete files in that post). Basically, there is a tiny risk; if you keep your cool and re-start the process if it fails (despite it emulating a brick at that stage), you'll almost certainly succeed. In the worst case, you need to replace the control card, which is less than US$100 (but quite a drama and time consuming). So it's not going to brick the entire inverter, no. But if you love totally off-grid and rely on the inverter for cooking your food, you might reconsider. but in that case, you really should have a pair of them paralleled, and only flash one at a time.

Thanks

Cassie

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1 hour ago, Coulomb said:

Is that with PV connected?

Thanks Coulomb,

Yes PV is permanently connected, except when I switch it off with the breaker.   But what is strange is that it switches on later in the morning and then charge like the other inverter (master) without problems.  What I gathered from this behavior is that the charge controller is working and that all cables are connected.   I took 2 pics again - and now it showed the firmware on it.  See below.

Slave_charge controller_normal2.jpg

Slave_charge controller_normal1.jpg

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At the time of morning when one works and the other doesn't, what are the PV voltages?

Is it possible that one has weaker PV power than the other? For example, due to less ideal orientation? Or a big bat splat on a panel or two?

That would go towards explaining the U2 00 00 behaviour.

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On 2021/08/24 at 2:46 PM, Coulomb said:

At the time of morning when one works and the other doesn't, what are the PV voltages?

I left this morning early and only came back this afternoon.  Will check tomorrow morning.   I think I did check it before and it was the same, but I'll make sure tomorrow morning.

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On 2021/08/24 at 2:46 PM, Coulomb said:

At the time of morning when one works and the other doesn't, what are the PV voltages?

Hi Coulomb,

Ok,  I managed this morning during cold and cloudy weather at 9:00 to take the measurements.  Again the PV volts on the slave (problematic one) was 92.4v and on the Master 91.8v .  I checked again a few minutes later and still no connection with the panels and the PV volts still close with the PV volts on the master (slave: 87.2,  master:  88.4V).

Then an hour later the slave was now connected and PV volts 54..9 and master =54.8v .  (with sun on the panels)

Another 30 mins later slave =88v, master= 88.1v (cloudy and cold) 

10mins later.  slave=53.7, master=55.2

From this I gathered that it is not the panels.  Can it be the old firmware (52.30) ?

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On 2021/08/27 at 7:30 PM, Cassie said:

Then an hour later the slave was now connected and PV volts 54..9 and master =54.8v .  (with sun on the panels)

That sounds a little unusual. Was it really weak sun? By 10am, I'd expect better solar voltage than that if there is no cloud and the tilt and direction are reasonable.

On 2021/08/27 at 7:30 PM, Cassie said:

From this I gathered that it is not the panels.  Can it be the old firmware (52.30) ?

I'm not certain that the panels are off the hook just yet.

53.20 certainly is old firmware, and I vaguely recall problems with PV on that firmware. It's certainly worth updating to something like patched firmware version 73.00e (note: not 73.00 factory firmware).

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On 2021/09/02 at 10:29 AM, Error 83 said:

Error 83

That's a masterpiece of brevity.

Are you asking what fault code 83 signifies?

The Axpert King manual says it's "Battery voltage detected different". Inspecting some firmware, it looks like a voltage difference of either 4.0 or 6.0 volts is detected between units that are paralleled or connected for 3-phase operation. That would indeed be a substantial difference.

So I guess check the battery readings, and calibrate any units that disagree more than one or two tents of a volt from the other(s). See the AEVA PIP-5048MS topic for how to calibrate the battery voltage readings.

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