Look at a single battery. If it has 3 removable caps on the top, it is a 6 volt battery. If it has 6 removable caps, it is a 12v battery. 6 volt batteries will be connected in series, plus to minus, to achieve 12 volt for the RV. 12 volt batteries will be connected in parallel, plus to plus and minus to minus, to also achieve 12 volt but with greater ampere capacity. With 4 or more 6 volt batteries you will have some combination of both parallel and series. Recommend reading your manual for the generator and your charging controls for its features.
2013 Flagstaff 8528IKWS, 2006 F-350 6.0L