[MRCA] bb-390 battery - strangeness

[W2HX]

Here's a strange one. I have a bren-tronics bb-390b/u battery (NiMH). It has two SOC (state of charge) 5-segment displays, one display for each 12V section.  The battery seems to function totally normally with respect to capacity, charging and discharging (using my bren-tronics soldier portable charger and discharger). But what is strange is that one of the two SOC displays will show 5 bars when fully charged but will still show 4 bars when totally discharged! I even ran that side of the battery down to 0.5V manually with a high power resistor still 4 segments showed. The other SOC display works 100% FB.

What I don't get is, what is keeping these segments "lit up"? I have discharged both sides of the battery to 0.5V and the SOC still shows 4 segments.  Where is it getting the power to illuminate the segments? Any ideas? I guess I should try running it down to 0V and see what happens. BTW: These 390 batteries seem to indicate 0% charge (0 segments lit) when the battery is discharged to 11V from 12V.  So just 1V separates empty from full.

Any ideas?
Eugene