I had the battery replaced at the dealer 3 months ago and drove it 900 miles since. No signs of a bad alternator or warning lights. Yet dealer says I need a new alternator. Service adviser at VW dealer wrote, “Battery failed load test but also found excess ripple detected. Replaced battery. Retest for bad alternator. Excess ripple is still present. Vehicle has proper charging voltage but excess ripple can cause alternator to overcharge battery and damage cell. Alternator needs to be replaced.”
Does that make sense?
A bad cell in a battery can cause an alternator to overcharge. Now that you have replaced the battery, the battery has a warranty. If you do not want to replace the alternator, don’t. The dealership is a business. This means they are going to recommend you spend more money with them, this is how they make money. Makes sense right. I see the term “can cause alternator to overcharge” I didn’t read IS OVERCHARGING AT PRESENT.
If you want peace of mind, replace it, otherwise wait till it stops charging.