Since we are on the topic of preparing for power outages, I recently switched from relying on a generator (which requires my being home) to a battery backup. The newer Tunze streams have the capability of being hooked up to a 12vdc lead acid battery, but you have to purchase their safety connector (nothing more than a connector with a fuse.) At 55 watts full blast, the 6201 should last 4-5 days easily with the large battery I am using. I also purchased a battery conditioner for $20 which keeps the battery fully charged.
Here is a pic:
