Battery Question
 

Question about our AGM battery in the FType. I've been doing some research and see that AGM batteries have some different voltage ranges than lead acid batteries. For example, AGM is considered 100% charged at 12.80 volts and 75% at 12.60 volts and 50% at 12.30 volts. I have noticed that my original (2017) battery after sitting overnight is around 12.40-12.43 volts, or, about 60% charged. I have not measured voltage over 12.60 percent even after driving the vehicle for over an hour. My auto start stop also does not engage even when the a/c is off. So my question is, is this a sign that my original battery is on its way out? Shouldn't it charge itself more than 75% and have enough juice to operate the start stop system?

Thanks,

I have a 2017 (MY18) and have noticed a similar effect- voltage at the dash 12V socket drops to around 12.2V after a run, having shown 14.7V when running. I rarely use stop/start but whenever I've forgotten to disable it, it kicks in, so I assume it's always ready to work. I do periodically put the CTEK on it overnight - do you ever charge your battery?

This was discussed quite a bit when the forum was discovering the OBD battery drain issue, IIRC.

I replaced my 7 year-old battery last week with a Duralast, and after two nights, the battery tender LED switched to green, showing fully charged. Just measured the voltage on the battery: 12.4V.

I´ve had the same problem on my MY 17. The dealer has downloaded a new update for the charging-system. Now everything is ok.
I also charged the battery with a c-tek 5.0 in agm-mode overnight during the problem. Then everything was ok for about 2-3 days.