Battery - should I change it?

Hello,





I have bought my car last year and everything has been good with it so far.

It is a 2002 320I with 60.000 km on the clock.

I have to mention that I haven't encountered any battery related problems...yet.



I checked the battery and it is a BMW one, might even be the one that came with the car.

Afterwards I have checked the voltages at the battery terminals.



12.2 V with the engine off

13.90 - 14.00 V with the engine on (only radio was on and the electric fan, plus inside lighting) - revving it doesn't seem to alter the voltage

When turning on the headlights (xenon), it dropped to 13.75V then in 1-2s raised back to 13.9 - 14V but the alternator seemed a bit noiser.



The battery also has that "eye" to check for it's health status and that thing is definitely black, indicating that it is not charged, but one day before my checks I drove the car for almost 1000 km non stop (highway speeds), so I guess it should have been charged.



I know it should be changed as preventive maintenance, but would like to still keep it if I can as a 80Ah good battery is around 100 euros.



Thanks!