could you tell me if the system uses 12 volts as a battery backup ? i am looking to putting this system into 4 garages/lock ups where there s no mains power, but i could use 12v batterys if this system runs on 12v when no mains power avalable, also is it a 12v supply that activates the siren, thank you.

Most domestic alarm systems use 12v batteries for operation during mains fail , these usually keep the system functioning for approx 8 hours depending on battery size.Some systems will not set with a mains failed.If you have no mains supply , look for a system that is designed for battery only operation.Try typing "void property alarm " into google ,that will give you a better idea.