SOC% reporting incorrect result. Bug?

This is the last I will say, we have had this issue many times, the only way to accurately monitor battery is to fit a shunt. As far as I know, the Quattro does not measure DC, there is certainly no shunt in there. What it does do is measure the ac in and the ac out and from this it estimates the DC current, which is why it is not very accurate and needed to use charging state and an SOC figure as reference to reset to a known point. Lead acids frequently hit the trigger point, lithium can go for weeks without getting recalibrated to the trigger point.

You argue it should do this or do that without actually knowing what the system does, but those of us who have experience fit a shunt. I would never rely on the inverter built in SOC.

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Sorry but just saying ā€œI know more than you, do what I sayā€ is not an answer.
If you want my respect then reply to my carefully reasoned question above which refutes what you say.
Are you telling me that the current measuring on the victron PV inverter and quattro are rubbish? If not where is my logic wrong?
I have explained to you how it is done, Iā€™m sure thatā€™s how victron are doing it (or should be).
The question is do YOU know how it is being evaluated, in which case please tell and we can have a discussion and/or workround.
Its really not comlicated.

Addendum, yes, the quattro has a shunt.
It can measure DC current to/from the battery.
How else would it control charging current and discharge current, which it can to avoid excess current to the battery.
Even a cheap Ā£20 charger can do this, itā€™s trivially easy.
So I am afraid that your statement is clearly wrong.

Regrettably, I am off-line until ~21:00 GMT today

Is it really true that the quattro estimates DC currents via the ac inputs/outputs?
That is absolutely dreadful design considering a shunt and dac are so cheap.
SOC should not be used as a control criteria if is so mindblowingly inaccurate.
At least battery voltage should be offered as an alternative, which is a cerbo software change which should have been done years ago.

You make too many (erroneous) assumptions. Too many to refute when we know youā€™re not listening anyway.
And you put words in the mouths of Victron engineers, who are indeed very capable at even the ā€œrocket scienceā€ level of SOC calculation.

Itā€™s why Victron recommend that installers donā€™t enable more than one SOC source in a system capable of more, because they rarely agree. And users get upset. A step further - in a GX managed system itā€™s possible to set preferred sources of Volts, Amps and Temp to apply systemwide. But not with SOC, the system will decide which one is best (by ā€˜pedigreeā€™), and if you have a personal preference you have to disable the others.

In your case the source is unknown, you havenā€™t looked, and certainly never made any adjustments to it. I suggest you do so, and perhaps while there take a look at, say, a Smartshunt manual to see what is actually considered when it calculates SOC. Not perfection, but it can get quite close. I actually am still awaiting a reply from the VRM Beta team who propose to delete the decimal point on SOC display. I say No, please! Yes it can be that goodā€¦

If you need help tuning whatever you find, ask a fresh question. This thread is best forgotten. Iā€™m closing itā€¦

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