Sudden shutdowns, no power up, bios battery?

(Latitude e7440, but general cmos battery \ bios question).

2 times got these stops, sudden power down, refuse to restart like no power or battery connected. Was streaming some YT music. No heat, no laptop movement.

Battery & psu ok (tested on other e7440). Tested with known working other psu & battery, still no boot, no power connected led blink). So, the end? Tried removing\swapping hd\ssd & memory, nothing. Then removed cmos battery and that worked. Reset a few things in bios (defaulted to raid!?) and all well.

Then a week later, same power down, power button no reaction, no power led light blink. This time removed bios battery with psu connected, immediately upon removal the 'power connected' led lighted up, laptop booting upon power button press.

Using the old faithfull latitude for streaming, browsing, travel, downloads, it's still an excellent machine, and hopefully will last for a while longer if that bios\power thing can be dealt with.

Measured the old cr2032, 2.7v = goodbye, so maybe sorted after fitting the fresh battery. All seems well for some days now. But would the low voltage normally make the bios go into this abrupt 'no laptop battery \ psu connected'? Maybe Dell's way of saying 'replace battery'? O)

 

Hopefully useful for some reader someday, so far the battery exchange did the trick, all stable and well. If getting strange shutdowns \ no power-up, spend a few minutes checking the cr2032 condition

 

And 5 weeks later... my i5 e7440 refused to boot. Same symptoms as above posts. Changed bios battery and all well (needed reset of some bios settings). Approx. same age as the above mentionned i7 e7440.