What happens to the battery while the Swann Security Doorbell is powered on AC?

Answer:

1. It charges the battery.
2. The unit will use the battery when power/AC goes off.

Nothing will change in how the unit behaves or how the features work; all that is different is you won't need to charge the unit now and then.

Visit this article to learn about the installation of the video doorbell to an AC power connection.