hi guys, i have a ups. how long would this last in the event of a power cut? i also have a spare 12v battery for this aswell, how do i connect it up? would it last longer, and by how long? or could i just connect a 12v deep cycle battery, bout 50 amp per hour. but would this cause the ups to overheat? would this last longer? what is the best options, with out robbing the bank?