Power from the alternator is a complicated thing.
The biggest drain of power is when you start the car - worst in winter, it will drain the battery alot. Any heating system will also put a massive drain on the battery. The actual power reqs of the basics to run the engine are very low, its the starting and "comfort" systems that are the biggest burden aswell as headlamps/wipers. Again in winter you are using them more too
If you intend running without an alternator you will need to know exactly the power needs for the regular journey that you do ie home to work. You will need to add additional batteries and charge via solar (again bad in winter) or wind (good in winter) to cover the vehicles needs.
If you get stuck in traffic you are screwed.
TBH I dont think its worth it to rewire new batteries and have a free power source that you have to connect after each drive. Just drive eco, dont put the sterio on full blast, max the heaters, seat heaters, steering wheel heaters and so on.
An alternator mainly only drains power from the engine respective from the draw needed from it.