Agreed on the variables, and considered that... using house batteries would otherwise be workable, but in cases where vehicle isn't situated for easy access, I'd need a pretty long connection to reach those batteries, an inconvenience I'm hoping to avoid... installing a separate battery, say, in close proximity to the cooler using it, would require no more than the connection that comes with the portable solar panel. Further, when the vehicle is being used and driven, the connecting & disconnecting of said house battery connection would be unnecessary. Greater portability and access to sunlight of the panel is also a potential advantage
