The battery voltage is always compared to the higher value of the back to utility (PBCV) voltage setting, or the battery low voltage (battery low cutoff setting (PSDV) plus 2.0 V (0.5 V for LFP patched firmware)).
I would always expect the back to utility (PBCV) voltage to be well above the battery cutoff (PSDV) voltage, but I don't believe that this is enforced anywhere. You might want the gap to be less than 2.0 V (0.5 V for LFP patched firmware), if you want to force the effective back to battery voltage to be non-integral.Or is it important that PBCV >(=) PSDV?
The compensated battery voltage is used for the decision to switch to line (bypass) mode; this partly involves the low battery cutoff voltage setting.I assume that the KettleKomp™ voltage is tested against PBCV and raw battery voltage against PSDV. Am I right?
[ Edit: As Weber states below, the low battery warning decision also depends on compensated battery voltage. ]
I can't seem to find the code right now that sets fault code 04 (battery low fault). I believe that it does not use the compensated battery voltage.