Is it Possible to run a 12v lighting grid from a car battery for 1 hour?

I am trying to illuminate 1 interior wall of a church for 1 hour but do not have an active power supply. The church has stated that candles are not permitted (health and safety!!!!) and I can not run a cable across the church (extension lead etc) so my only option would be to use a car battery. I would hope to use 4-6 12v 10-20w dichroic spots to wash light up the wall. Is it possible ro run this type of circuit form a car battery?