Battery Life: Charging Voltage & Optimization

Hello everyone!

Meine Starterbatterie Moll M3 83075 (75Ah) ist jetzt bald 5 Jahre alt. Bei den momentan niedrigen Temperaturen beginnt sie ein wenig zu schwächeln. Letztens drehte der Anlasser nach Vorheizen per Standheizung nur noch müde, hat es aber geschafft. Derzeit habe ich ein Multimeter zum Messen der Bordspannung am Zigarettenanzünder angeschlossen. Heute morgen war dann alles normal, -7°C, 12V nach 25min vorheizen, Motor gut angesprungen (Spannung dabei wg. Kürze des Ereignisses leider nicht ablesbar). Einige Stunden nach Abstellen liegt die Spannung bei 12,7V. Wahrscheinlich kommt die Akkuschwäche durch drei Faktoren zu Stande. Alterung, niedrige Temperatur, viel Stadtverkehr (vor dem „Schwächeanfall“). Soweit Okay.

However, what concerns me is the charging voltage of the alternator: 14.5V. While this corresponds to what "How it's done" states (13.5-14.5V), it seems a bit high to me. I have something like 13.8V in mind, especially if the battery is supposed to remain connected to the power source even after charging. This naturally explains the water consumption of about 100ml per 10,000km. Fortunately, the Moll coolant reservoir is refillable. This means that after 150,000km, the battery has likely been overcharged for approximately 2500 hours. However, the performance is still quite impressive despite this.

Okay, here's the translation:

Now, my questions:
1.) What is the charging voltage for you?
2.) What battery (manufacturer, type) did you use, and how long did it last?


Regards,
mcgregg

Charging voltage measured between 14.6 and 14.7 volts using a VAGCOM device.
"The original battery in my 2001 Golf IV also started to weaken this winter."

and what is the saying? 'He who measures, measures manure.' Nowadays, all battery chargers operate at 14.4V .
With a car that's 13 years old, your battery should still be in good condition after you turn off the engine (provided there are no electrical devices drawing power).

'You won't notice how powerful your battery is when you measure its resting voltage. What matters is the internal resistance of the battery when starting, or rather, what current it can still deliver. Consequently, the voltage drops.'