Battery drain protection/power save mode?

[evolver]

Hello, fellow X-fivers!

It has been a while since I've been here, mostly provided to how well my E70 ran for all this time

However, in the past couple of days it began to show some symptoms that I attribute to the failing battery. The symptom is that in the morning when the vehicle was not locked overnight, pushing the liftgate release button on the liftgate itself does not do anything. Then, when I open the driver's door, the whole dashboard lights up for a fraction of a second, then I hear the fuel pump pre-pressurizing the fuel-lines and the engine is ready to start. Once I start it, the computer complains about an excessive battery drain and the clock is reset. Well, the time is reset and the date appears to be lagging while the clock was not running.

The engine cranks up happily with no audible sign of underperforming battery, and it starts normally.

Does this all sound like a case of a battery getting ready to die? Does the E70 have electrical protection mechanism that puts the in-car electronics into a power-saving mode if it detects a chance of a battery draining below the level when the engine cannot be started?

I have the original 4-year old battery.


Regards,
/Sergey