Yes, the day/night solar vent models have batteries, my point was the model has to specifically be a day/night version. Nicor/Marinco still makes a non battery solar vent (n20020) and used to make (not sure if still available) a 4” solar vent that could be wired into the 12v system but did not have an internal battery.
The non battery options have slightly smaller hole sizes than the day night models, so if you are replacing an old model it is important to know if you have a day/night model or not.
Moot point now for the poster, but could come in handy for someone else. It is possible in my case the original Installation of my first generation day/night had the hole slightly oversized.