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rolandchart avatar image
rolandchart asked

AGM super Cycles Cerbo Percentage not reflecting the voltage

I’ve a bank of 4 170amp super cycle AGM batteries. They are great batteries and I’ve been careful not to discharge them too deeply over the couple of years I’ve had them


One thing that’s never seemed to work properly is the percentage on the cerbo in terms of it matching the voltage. It’s way out as the screenshot shows.


I’ve searched the forums and can’t seem to find a solution that works. Any suggestions welcome

img-2858.pngimg-2857.jpeg

cerbo gxSmartShuntSOCAGM Battery
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img-2858.png (171.3 KiB)
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Alexandra avatar image
Alexandra answered ·

@rolandchart

When are talking years and AGM you will need to be compensating for capacity loss.

You are right 12v is not 74% especially with a 69W load. What are the AH drawn?

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rolandchart avatar image rolandchart commented ·

272Ah discharged. I’m sure it’s never reflected properly.

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pwfarnell avatar image pwfarnell rolandchart commented ·
Is most of your discharge at low rates because if it is the Peukert calculation will be showing that the SOC is falling slower than the consumption of Ah due to the higher capacity at lower discharge rates. I calculated that for my Victron AGM telecom batteries that the Peukert coefficient is about 1.13 so you get less of a capacity boost in the SOC calculation with low discharge rates.
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