Hi OneCold.
If ever in doubt, look at the battery. Every cell (hole, plug) on a normal battery for car, boat, bike, forklift etc. is 2 volt. Just multiply cells X 2volts. So, yours will have
6 cells =12 volt
When batteries are connected to each other things change as they could be either paralell or in series but with single batteries you can't go wrong doing it this way.