Alternator on the way out

[donmi]

Hi guys,

new to the forum, but did some research about this problem.
I got a beautiful 2005 X5 4.4i, fully loaded, except Nav and Air Suspension.

Two days ago, during driving on the Highway, some lights on the dashboard came on (DTC, ABS, Fasten Seat Belt, Airbag, Transmission.....) So, I stopped, shut the engine off, tried to restart, nothing, not enough battery power.
After I waited 10 minutes, I could start the engine again and the lights were off and I could drive 100 km on the Highway without issue.

One day later, I drove and after 30 km, same thing happened and additional I lost the power of the engine (low voltage) and I was stranded on the side off the Highway, could not restart and ended up on the flatbed of a tow truck.

At home I checked the battery and it was only charged to 25%. Overnight I charged the battery and did a load test in the morning, absolutely fine, checked the voltage with running engine (and driving) and got between 13.8 and 14.1V.

I think, the alternator is on the way out, BUT is it possible that this happens intermittent???

Thanks for your attention.

Michael