12 Volt Battery Observations

[murphy]

I have observed what I think is a good indication of a low 12 volt battery.  
I have a voltmeter plugged into the 12 volt power tap that is located in front of the shift lever.

http://www.amazon.com/gp/product/B00962CQNC/ref=oh_details_o05_s00_i00?ie=UTF8&psc=1

When the car is turned off and the driver's door is opened the radio shuts off.

If the 12 volt battery is low the voltmeter shuts off at the same time as the radio.

If the battery is not low the voltmeter stays on for a time that I don't have the patience to measure but I think is around 45 minutes.


I drove the car 21 miles yesterday in two 10.5 mile segments.
The entire trip was in EV mode.
When I got home I recharged the HVB.

This morning I attempted to turn the car on in accessory mode but the MFT screen stayed off and I got the low battery warning on the left display.

The battery charging TSB was installed a few weeks ago. It has had little to no effect on the low battery problem.

I hooked up my 12 volt battery charger and it indicated the battery charge level was 80%.

Basically I can't do anything with the car unless it is in run mode so it can charge the 12 volt battery.