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P Markowski avatar image
P Markowski asked

Charged Voltage setting changed on SmartShunt + diffrent readings of voltage by mppts vs SmartShunt

screenshot-20240520-124128-chrome.jpgscreenshot-20240520-123000.jpgHi, today I had this incident on my instalation I have 820Ah lithium battery bank monitored by Cerbo+SmartShunt and 2x 100/30 MPPT connected to it. Charged voltage of my batteries was set in SmartShunt as 14.4V, batteries were like 82% and charging from solars. after few minutes I checked state of charge and saw thay batteries are showing 100%, after short check of settings in sysem I found out that "Charged Voltage" setting was changed to 13.5V in SmartShunt - I had to change it back to 14.4V, and manualy set State of Charge to 83%.... Did You ever had this issue? Everything was working fine for last few months. I notice that my MPPTs are showing different Battery Voltage that SmartShunt, is it ok? - I guess its because they are charging, right?

MPPT SmartSolarSmartShunt
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pwfarnell answered ·

Have you recently done a firmware update, these should leave the settings as they are but occasionally there is a change to default. The charged voltahe setting should ideally be 0.1 or 0.2V below absorption.

When charging, the MPPT will often have a higher voltage due to voltage loss in the cabling. The SmartShunt should have the most accurate voltage reading because it is closer to the battery. Check the MPPT voltages when it is dark and not charging and they should be the same. As you have a Cerbo and I assume all devices are connected to the Cerbo, go into the settings>DVCC menu and enable DVCC, SCS and SVS ( share current sense and share voltage sense) and choose the SmartShunt as the source if required. Everything connected to the Cerbo will then use the SmartShunt voltage and current readings so everything is working on a common base. This will mean the MPPTs will go to a higher voltage if needed to offset the voltage drop.

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P Markowski avatar image
P Markowski answered ·

MPPTs showing same value when batteries are 100%, thanks, but still im not aware of any SW update on smartshunt, is there a way to check when was the last one?

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pwfarnell avatar image pwfarnell commented ·
I do not know of anyway of checking firmware history. It should not update on its own, only manually implemented.
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P Markowski avatar image
P Markowski answered ·

so if it was not updated automatically, how the hell it was changed back to 13.5 ... :/ Now im not sure if i can trust that bloody device.

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