Cerbo GX creating incorrect Solar power figures on VRM dashboard ( solar production at night !)

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ceychene asked Feb 12, '24

Cerbo GX creating incorrect Solar power figures on VRM dashboard ( solar production at night !)

Hello Victron team, here is a very strange (and annoying) phenomenon:

Since two days, after having had a BMS loss due to Battery internal error (too low SoC reached – since then recovered), my VRM Dashboard is showing irrelevant values for Solar production approximately when the PV is not generating any power. It seems the Cerbo GX is “inventing” Solar power to “fill the gap”. For the date of Feb 12th e.g. the Inverter RS shows in the console a cumulated daily solar energy of 3kWh which is what I can see on the Dashboard from 8am to 6pm, which is correct and compatible with the SoC gained this day (18% to 44% of a 9.6kWh Pylontech). However the VRM Dashboard shows IN ADDITION a sustained 1kWh per hour from 6pm on the previous day to 8am this day (all at night, I am in France, north hemisphere!).

At the same time, on the VRM Advanced panel, the RS 48/6000 PV Voltage chart shows no value from 6:29pm previous day to 7:45am this day.
Same thing happened one day before (just after the low SoC issue).

I guess there is a link between these two behaviours but what is the cause of Cerbo not recording any value from RS over those 13 hours ? Could it be the RS not sending ? And why does it invent those 44kWh at night ?
Shall I reboot the Cerbo ? or else ?

My setup is RS 48/6000 with Cerbo GX and 4 Pylontech , powered by a 3kw-peak PV panel, no connection to the grid. Everything had run with no issue for the last 3 months.

Cheers

cerbo gx inverter rs

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ceychene answered · Feb 14 at 08:12 PM

Hello,

I upgraded Cerbo to 3.20 and RS to 1.15 (did not find how to get 1.16) earlier today.

Then I made the test again : after having watched the PV Voltage decrease well under 70v, at 18:42 I changed the RS to 'charger only' then at 19:23 back to 'on'.

The result is below, showing no improvement, still some Solar power 'found' by Cerbo on the Dashboard, while PV Voltage has 'disappeared'.

PV Voltage graph from RS is taken from VRM Advanced page.

Cheers,

Christian

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JohnC ♦ commented · Feb 15 at 04:42 AM

@ceychene

Victron Connect sometimes doesn't carry the latest fw's. Online updates should, but Victron Professional has it as a standalone file (signin needed there). The next update to Connect should get it, if you can wait.

Best to try for 1.16, there was some VRM stuff mentioned in the changelog. Nothing definitive related to your issue, but who knows..

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ceychene answered · Feb 15 at 08:21 PM

Hello!

1) Inverter RS now upgraded to 1.16 thanks to VRM>Devices_list menu. I did not know it could be different from Victron Connect. Maybe a warning on the doc or in the app could help ?

2) checked again with same protocol tonight: RS to 'charger only' at 19:29 then back to 'on' at 20:16 while no more sun and no AC load.

3) * no wrong figures on the Dashboard anymore ! * Looks like the 1.16 has fixed the issue.

4) but RS Graph for PV Voltage still shows a gap in the data while in 'charger only'. This is hard to understand as the MPPT is the best possible source for this measurement. I guess it is done by another function tied to the Inverter and muted while not inverting.

5) New weird thing appearing today: the SoC remained stable at 89% for two hours while 1.15kWh of Solar energy was produced (575W avg), then rose up to 100% in just 23 minutes while the power was hardly 40W. This SoC reporting delay might have been caused by the Pylontech BMS itself so I just report it here for convenience. I will certainly monitor next days (could be hazardous...). No warning whatsoever. There was no AC load.

Enclosed the two graphs:

Cheers,

Christian

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JohnC ♦ commented · Feb 16 at 08:14 AM

@ceychene

Ok, seems you've fixed the main issue. Good work.

The others are likely separate things that you can investigate (and report on) as you will. If the SOC is Pylontech derived then you might find answers by searching the Pylontech related threads.

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Answer 1 · 2024-02-13T03:44:08Z

JohnC answered · Feb 13 at 03:44 AM

Hi @ceychene

Such weirdness might be just a digital knot that needs straightening out. Try the reboot first. Then maybe reseat all the cables, but keep your eyes open for clues while doing this.

Even if this fixes it, it doesn't mean that lost or corrupted data is recoverable, so look at current values when assessing.

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Answer 2 · 2024-02-13T07:44:39Z

ceychene answered · Feb 13 at 07:44 AM

Hi @JohnC thanks for your swift reply.

More information: this behaviour happened when the Inverter RS was in 'Charger only' Mode, either automatically as a consequence of low SoC (Feb 10-11th) or because I switched it as such on purpose to ease SoC recovery (Feb 11-12th). I notice that the lack of PV Voltage values started in both cases when the MPPT reached its low voltage threshold. This is confirmed as on the 12th, a few minutes after I wrote my message, the case happened again (missing PV Voltage, and Solar energy showing up on Dashboard). I then switched the Inverter back to 'ON' (full function) and everything came back to normal (ie 0 volts shown and no production - we were at night again).

So:

1) the quick fix is to *not* stop the Inverting role

2) it is strange that the RS would not send PV Voltage values even below MPPT threshold while in Charger only mode

3) this does not explain why the Cerbo creates placeholder values on Dashboard. I would see this as a bug.

Now I will reboot the Cerbo GX and test again next evening. Will let you know.

Additional Question : what is the source for Solar energy figures shown on the Dashboard ? I could not find any widget with the same figures on the Advanced page. And PV Power widget from the RS was always correct.

Cheers

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Answer 3 · 2024-02-13T21:43:04Z

ceychene answered · Feb 13 at 09:43 PM

Behaviour confirmed : Dashboard 'Solar' value has been zero since 18:30 (as expected after sunset). I switched the Inverter RS to "charger only" at 22:06 then back to "ON" at 22:19. Dashboard "Solar" value shown on the 22:00-22:14 slot = 0.45kWh (equals to 3kW+over 8 minutes). Then 0.23kWh on the 22:15-22:29 slot (again equals to 3 kW+ over 4 minutes). Zero since back to "ON".

Disabling Inverter function while MPPT is inactive creates erratic 'Solar' figures on Cerbo GX Dashboard.

Cerbo GX had been rebooted this morning.

Cheers

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JohnC ♦ commented · Feb 14 at 05:36 AM

@ceychene

Ok, might be a bug. I've highlighted it at a higher level, hopefully someone can contribute. In the meantime add whatever you can think of that might help to diagnose it. Even screenshots, which sometimes show more than words can.

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Answer 4 · 2024-02-14T09:30:59Z

ceychene answered · Feb 14 at 09:30 AM

OK.

Here is the first graph showing the bug when the Inverter was stopped from discharging by BMS around 2am, then MPPT began to charge around 8am. If needed I can provide two others when the Inverter was switched manually to 'Charger only' but it looks the same.

and this is the PV Voltage graph on the same period.

Inverter details:

Cerbo GX details:

Hope this helps !

Cheers

Christian

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JohnC ♦ commented · Feb 14 at 10:29 AM

@ceychene

Mvader (CEO) has asked if firmware is up to date? Should've asked this myself, newer kit often needs a touchup. I note your Cerbo isn't, so best bring everything up to date, including the RS itself.

Latest Cerbo is 3.20, the RS 1.16

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Cerbo GX creating incorrect Solar power figures on VRM dashboard ( solar production at night !)

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