Time sensitive: "Shutting down system to save power"

[CarlPace]

Well, my wife is stranded in a parking lot with our FFE...

She can't remember the exact message, but she went to turn it on and it said something like "System shutting down to save battery", or the topic. No it's giving no response...

Any ideas? Is this just the 12V battery that needs replacing?

 

[CarlPace]

Aaannnddd we're all good, It was just the 12V.

Phew...

 

[Anti_Climax]

FYI, you'll see that if the float voltage of your 12V is lower than the stock battery.

If you install an optima battery in a gas Focus is will say that if you shut the car off and keep running the stereo from accessory.