U27-12XP says 83% SOC, yet 10.7v

[txfamilycamper]

Hi,

With a recently purchased (used) U27-12XP, I could use some help diagnosing what's going on.

I have it installed in my 5th wheel RV. After a full charge (~10 hours on PD9180ALV), several hours I have it connected to the software, and it's reporting 83% SOC, yet is only yielding 10.7V. I guess my question is what would cause the software to be reading this SOC while yielding such a low voltage?

 

[snoobler]

Without knowing how the battery monitor works, it's impossible to say exactly why; however, battery monitors typically require charging to full or near full on a regular basis to ensure the % SoC value doesn't drift.

Another possibility is that your used battery only has a tiny fraction of its rated capacity remaining. Battery monitors also typically work by "counting" Ah in and out and compare that to the RATED expressed as a %.

I suggest you recharge the battery to 14.6V with a tail current of 11A (terminate charge when current tapers to 11A), confirm SoC indicates 100%, note WH Dsch value, and conduct a discharge.

Probably worth checking the Event Log and Batt System Info tabs.

EDIT: When charged confirm peak cell voltages of 3.65V.