question

sebastiansch avatar image
sebastiansch asked

SOC is wrong

Hardware:

-Multiplus 48V/3000W

-Cerbo GX

-EM24

-Lithum Batterys 47V => 0% ; 57V =>100%

-No shunt

-BMS: JK (without any connection to the multiplus)

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i Activate the check box "Enable Battery Monitor" to see the Procent value of the Battery.

multiplus2-allgemein.jpg

I have the problem that i see the wrong SOC (%) Value in the app. Voltage is ok.

wrong-soc.jpgwhatsapp-image-2022-11-07-at-133457.jpeg

May the problem is drift in this winter by the low voltage.


I think this is the often disgussed problem in this Forum but i did found the Solution.

Best for me will be an procent value ony depent by the Voltage.

Sorry for my worst english (i'm German)

best reguards

Sebastian S



SOC
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4 Answers
Al avatar image
Al answered ·

Either find a way to integrate the BMS in venus, or get a smart shunt / BMV.

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kevgermany avatar image
kevgermany answered ·

@SebastianSch

Du kann auch in Deutsch Fragen.

Jetzt in Deutschsprachige Bereich

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steffen-graap avatar image
steffen-graap answered ·

Die Schätzung des SOC durch den MP ist nicht gerade genau.
Entweder verwendest du ein SmartShunt, welcher per Konfiguration an dein Akku angepasst werden kann, oder du benutzt die Daten deines BMS). JK-BMS sollte über den dbus-serialbattery-Treiber von Louisvdw funktionieren. Link hier.

Die Spannung der Batterie ist keine Option für die Bestimmung des SOC. Einerseits hast du eine recht flache Kennlinie der Batterie, anderseits hast du Spannungsabfälle am Innenwiderstand der Zelle, die die außen gegessene Spannung von der tatsächlich inneren Spannung der Zelle abweichen lässt. Die bessere Variante ist eine Ampeerstundenbilanz, wie sie von BMS und SmartShunt verwendet wird. Problem hier ist zu wissen, was gerade das aktuelle Fassungsvermögen der Batterie ist, damit man das Verhältnis (SOC) von möglicher Kapazität zur Bilanz richtig berechnen kann. Deshalb gibt es die Syncronisierungsfunktion, um Fehler hierin auszugleichen.

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rotevery avatar image rotevery commented ·

I have smart shunt and I'm tired of having to synchronize from time to time. I'm not sure it's worth the investment. There should be a reliable meter that needs less maintenance.

Quattro measurement (which I use in another site) has similar errors and I don't know how to synchronize that one.

The BMS had been better been accurate.

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sebastiansch avatar image
sebastiansch answered ·

Ok danke für die schnellen Antworten....ich versuche es mal mit dem SmartShunt.



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