Battery indications - Bavaria 30 2005

[Fairweather sailor]

Hello. We recently replaced our no 2 (services) battery as it was not holding a charge. On our panel, the first two way switch allows us to check battery voltage either for battery 1 or battery 2.
We assume the second switch immediately below shows whether the battery is charging or not.
Shore power has been connected for the past week, both batteries are showing voltages of 13.2 (approx)
When I press the second switch to Battery 1 side - it reads zero, however
when I press the second switch to Battery 2 side - it's reading just shy of 12 volts.
Shore power is connected while doing this check.
Can someone explain why I'm getting this reading on battery 2 when pressing the lower switch. Sorry if it's confusing!!
Thank you.

[Keweetoo]

Your guage is dual battery and tank (water) fill status. The lower switch you are pressing give the capacity of your two water tanks - nothing to do with batteries so tank 1 is empty and tank 2 50% full. Both your batteries appear to read 13.2v so presume they are being charged.

[Fairweather sailor]

Thanks very much for taking the time to respond, makes sense, as we only have 1 water tank and its aft. We do have the owners manual, but it's really short of information on the boats systems and indications.
Thanks again.