I'm Confused?

MSGTRETIREDCSP wrote:
I just removed two 6v batteries from my fifth wheel rv. I'm going to replace them with two 12v batteries. When I removed the 6v batteries, there was one wire running from pos to pos on the two batteries. There were two large white wires from the rv and going to the neg post of one battery. There was also two large black wires going from the rv to the neg battery post of the other 6v battery. With the one wire that was running from pos to pos of both batteries, that tells me that they were both wired in parallel? Am I right? What confuses me is if they are both 6v batteries, wouldn't they need to be wired in series to get 12v in an RV that is 12v?
My fear is installing the two new 12v batteries. I don't want to wire the same only to find out it's wired in series. I don't want to screw things up with 24v.
Can you help me out? Thanks

Two 6 volt batts need to be wired pos on one batt to neg on the other batt to make up a 12v batt.

Then the load pos and neg goes on the other batt posts not being used.

Reading your description it is impossible. The two black (pos) wires should have gone to the pos post of one of the 6s not the neg post. The two white wires should have gone to the neg post of the other battery, which they did.

I can't figure out how you ever got anything as it was. Perhaps you didn't need to swap 6v for two 12s, but just got the wiring right on the 6s.