Hi, A local alarm company has given me a quote, and they want to connect the power to the alarm as follows: The 30VA 16VAC transformer is connected to a 7ah 12V battery. The battery apparently can run in AC mode, this was news for me. The alarm requires AC power, and is connected in parallel with the battery. They claim the alarm will run from the mains power if mains is on, but the battery will provide backup power when the mains are off. What concerns me is there is no charger for the battery in the setup. I don't know about AC charging, but wouldn't this setup cause the battery to permanently overcharge? Potentially be a fire hazard?