hanszwicky avatar image
hanszwicky asked

Cerbo GX bug ? MPPT stops power production in ESS when BMS CCL is set to 0

I think the title is pretty self explanatory, I found myself in a situation where I cannot get the MPPT to produce any power (or almost zero) when the pylontech bms say the battery is full.

Additional information: I work in ESS mode 1 (keep battery full), and I have DVCC enabled, as per the guidelines here:

and Here:

Of course I have feed-in enabled.

This setup was perfectly working just few days before I started to update my cerbo GX and multiplus 2 firmware upgrade. That's why I am thinking about a regression

Side note: My issue seems very close to this one:


Multiplus-IIcerbo gxESSDVCCfeed-in limit
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2 Answers
hanszwicky avatar image
hanszwicky answered ·

Ok, so I got the final conclusion to a question I saw more than 10+ occurences in this very forum without any proper conclusion (in my opinion).

I must warn you that the solution I found is OUTSIDE of official requirements from victron compatibility guidelines found here:

IE, the key for me was, despite the guidelines, to disable the “Enable battery monitor” function:


Be very careful about this because, this section get automatically checked when you run the ESS assistant utility, which makes it even harder to notice.

By the way, with this disable, I got my DC string/mppt to produce at full power all the time (within the feed-in restriction I set though), feed-in exactly up to the limitation I set up. I still get my pylontech bms as a source of truth for battery monitor in cerbo: system setup/battery monitor. So in the end I think the result of this action is related to some internal hidden logic of the GX. I'd love to get feedback from victron developer about that.

I am very happy about the outcome of this painful search journey, but I think I learn few interesting things along the way.

I still think that this is a bug in my humble opinion, but I'll let Victron specialist confirm or disprove that.

Hope this can be useful to someone as well, but remember that this "fix" is outside of pylontech compatibility guidelines from victron.

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harry4516 avatar image
harry4516 answered ·

thank you @HansZwicky for the detailed description. I have the same problem, sometimes. There are days where it works perfectly, the other day my MPPTs are switched off and sometimes switched on after 10 or 20 minutes.

I will try your solution, since this battery monitor is not used with pylontech batteries.

It would be really great if a victron engineer looks at this problem.

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