The Villa 9210 is designed to accept 12V DC power from battery or solar resource, or the AC converter - on standard AC power. It's the perfect unit if you may be changing from on grid to off or vise versa. This is the unit most commonly used for Tiny Homes as the fan draws less air for smaller spaces.When on DC power the unit uses 12DC/ 2.5 w / 210ma. 0.06kwh/24hrs. Capacity requirement for your DC power system will vary by location and installation. General requirements are as follows:Battery 60 to 75 amp.Cell size around 25 watts. Depending where you are in USA south smaller size north larger size.For installation in locations what are not used for period of time, and power is not continual, we recommend that when closing your location, you place the lid on storage container to eliminate the need for ventilation. Upon return, remove the lid and restart the fan for proper ventilation.