How heavy is the battery? or do you have to stay connected to the wall outlet? The only climate control system I am aware of that can be used in this setting a

How heavy is the battery? or do you have to stay connected to the wall outlet? The only climate control system I am aware of that can be used in this setting are Peltier effect based systems, and they are dogs in term of energy consumption if you can't put fan or other thermal pump.