My plan for a large scale disaster is mostly to use as many non-electric items as possible, by using as much 1800’s tech as possible. However, just because the grid is down, doesn’t mean its all little house on the prairie. Additionally, most of us have generators that could be used for short duration problems like floods or winter storms.
I am a big believer in solar power where applicable. Even though I know that solar electric power is not the most efficient use of sunlight, it can be effective when managed properly. To that end I even published a post about solar items like ovens and water heaters.
Managing 12 Volts is a great reference to have on your homestead, or BOL (bug out location). Especially if you plan on using 12 volt batteries to power things like radios.
This makes even more sense now that the recreational fields have so many consumer electronics build to run on dc.
This is where this book come in, it is designed for small scale systems like RVs and sailboats. It contains many good charts, tips, and best practices when building, maintaining, and repairing 12 volt systems.
Managing 12 Volts is not a design manual, but there are some useful information to help you know what to look for if you are designing your own system.